Ex Parte Zhou et al

Patent Trial and Appeal Board

Jun 21, 2018

13485657 (P.T.A.B. Jun. 21, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/485,657 05/31/2012
6147 7590 06/25/2018
GENERAL ELECTRIC COMPANY
GPO/GLOBAL RESEARCH
901 Main Avenue
3rd Floor
Norwalk, CT 06851
FIRST NAMED INVENTOR
ZhiZhou
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
246233-1 4759
EXAMINER
MERKLING, MATTHEW J
ART UNIT PAPER NUMBER
1725
NOTIFICATION DATE DELIVERY MODE
06/25/2018 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address( es):
haeckl@ge.com
gpo.mail@ge.com
Lori.e.rooney@ge.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE
THE PATENT TRIAL AND APPEAL BOARD
Ex parte ZHI ZHOU, 1
James Robert Presley, Russell Stephen Demuth, and Ming Yin
Appeal2017-009699
Application 13/485,657
Technology Center 1700
Before CATHERINE Q. TIMM, MARK NAGUMO, and
CHRISTOPHER L. OGDEN, Administrative Patent Judges.
NAGUMO, Administrative Patent Judge.
DECISION ON APPEAL
Zhi Zhou, James Robert Presley, Russell Stephen Demuth, and
Ming Yin ("Zhou") timely appeal under 35 U.S.C. § 134(a) from the Final
Rejection2 of all pending claims 10, 11, 13, 15-17, 21, and 30. We have
jurisdiction. 35 U.S.C. § 6. We reverse, but enter a new ground of rejection
pursuant to our authority under 37 C.F.R. § 41.50(b ).
1 The real party in interest is identified as General Electric Company.
(Appeal Brief, filed 23 January 2017 ("Br."), 2.)
2 Office Action mailed 21 July 2016 ("Final Rejection"; cited as "FR").
Appeal2017-009699
Application 13/485,657
OPINION
A. Introduction 3
The subject matter on appeal relates to a method for providing
electrical power on board an aircraft via a hydrogen fuel cell wherein the
hydrogen is generated on board by the catalyzed generation of hydrogen from
water in contact with a metal in a reaction meeting certain specified
thermochemical conditions.
Sole independent claim 10 is representative and reads:
A method for providing electrical power on-board an aircraft,
the method comprising:
generating hydrogen on-board the aircraft using a reaction
between water and metal;
supplying the generated hydrogen to a fuel cell on-board
the aircraft;
generating electrical power at the fuel cell using the
generated hydrogen, wherein generating hydrogen on-board
the aircraft using the reaction between water and metal
comprises
pumping, with a pump, the water through an inlet in a
bottom wall of a reaction chamber such that the reaction
between the water and the metal begins at the bottom of
the reaction chamber; and
controlling the pump
to control the flow rate of water into the reaction chamber
to provide a flow rate of hydrogen that corresponds to a
desired rate of electrical power generated by the fuel cell,
3 Application 13/485,657, System and method for providing electrical power,
filed 31 May 2012. We refer to the "'657 Specification," which we cite as
"Spec."
2
Appeal2017-009699
Application 13/485,657
wherein generating hydrogen on-board the aircraft using the
reaction between water and metal comprises
combining the water with the metal and a catalyst to
create an exothermic reaction having a temperature
range of between approximately 15 °C and
approximately 2 80 °C.
(Claims App., Br. 5; some indentation, paragraphing, and emphasis added.)
The Examiner enters the following new grounds of rejection4' 5 :
A. Claims 10, 11, 13, 15, 16, 21, and 30 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Tonca6 and Kindler. 7
Al. Claim 17 stands rejected under 35 U.S.C. § 103(a) in view of
the combined teachings of Tonca, Kindler, and Baker. 8
B. Discussion
The Board's findings of fact throughout this Opinion are supported by
a preponderance of the evidence of record.
Zhou urges the Examiner erred harmfully in finding that the disclosure
by Tonca of a reactor containing liquid water at a pressure of 120 psi
indicates that Tonca describes a water-splitting exothermic reaction "having a
temperature range of between approximately 15 °C and
4 Examiner's Answer mailed 2 May 2017 ("Ans.") 2--4.
5 Because this application was filed before the 16 March 2013, effective date
of the America Invents Act, we refer to the pre-AIA version of the statute.
6 Florian Tonca, Hydrogen generator, U.S. Patent No. 7,534,275 B12
(2009).
7 Andrew Kindler et al., Method and system for storing and generating
hydrogen, U.S. Patent No. 7,951,349 B2 (2011).
8 Bernard S. Baker and Hossein G. Ghezel-Ayagh, Fuel cell system, U.S.
Patent No. 4,532,192 (1985).
3
Appeal2017-009699
Application 13/485,657
approximately 280 °C," as required by claim 10. (Reply 2, 1st para.) In
Zhou's words, "[t]hat the temperature in the reactor 110, at the operating
pressure of 120 psi, may be 172°C or lower does not establish, by a
preponderance, that the temperature of the reaction in the reactant unit
cells 30 is within, or overlaps, the claimed temperature range." (Reply 2,
ll. 4--7.)
Although we consider the Examiner's new ground of rejection not
without merit, we cannot determine, on the present record, whether the
exothermic reaction having a temperature range of between about 15°C and
about 280 °C has necessarily been met. 9
Zhou urges further that "Ton ca does not disclose or suggest the
claimed reaction[,] as the reactant compound in each cell [of Tonca] does not
include a catalyst, instead the reactant compound comprises a metal and an
anti-passivation material. See [Tonca] column 5, line 61 through column 6,
line 19." (Id. at 11. 11-13; underscore added.) This argument is not well
9 In the event of further prosecution, it might be fruitful to clarify the
meaning of the limitation "an exothermic reaction having a temperature
range .... " In the principal Brief on Appeal, Zhou argues that "[t]here is
nothing in the disclosure of Tonca, including the disclosure of the operation
of the buffer 150, that discloses, or even suggests, and most certainly not by a
preponderance, the temperature of the reaction in the reactor 110." (Br. 4,
11. 1-3; emphasis added.) Zhou's argument in the Reply is similar. But a
characterization of the "heat of reaction" is more commonly in terms of an
energy per mole of a reactant or product (e.g., joules/mole), rather than a
temperature, which can depend on many factors, including the heat capacity
of the reactor and its contents, the efficiency of cooling of the reactor, etc.
Consistently, as discussed infra, the '657 Specification appears to use the
term "temperature" as a measure of the heat released by particular chemical
reactions.
4
Appeal2017-009699
Application 13/485,657
taken in view of the disclosure in the '657 Specification and the disclosure in
Tonca.
The '657 Specification reveals that a suitable reaction for the
generation of hydrogen from water is the reaction of water with aluminum.
(Spec. 11 [0029].) According to the Specification, "[a]ny suitable catalyst
may be used." (Id.) In particular, the following reaction is disclosed:
"2AL + 6H20 +catalyst= 2AL(OH) [sic]+ 3H2 +catalyst+ heat (between
approximately 15 °C and approximately 280 °C)".
(Id. at sentence bridging 11-12.) 1° Cursory review of this reaction equation
indicates that it is not balanced, that is, there is a deficit of four hydrogens
and four oxygens in the products (right hand side) compared to the reactants
(left hand side). The ordinary+ 3 oxidation state of aluminum is also not
satisfied in the formula "AlOH." These problems are eliminated in the
following corrected equation, in which the subscript "3" has been added to
the "Al(OH)" product:
2Al + 6H20 +catalyst= 2Al(OH)3 + 3H2 +catalyst+ heat
Inspection shows that two aluminum atoms, twelve hydrogen atoms, and
six oxygen atoms occur on each side of the corrected reaction equation.
10 The next two sentences of the Specification describe two other water
splitting reactions that lead to different aluminum products and three moles
of hydrogen, and more heat (higher temperatures). (Spec. 11 [0029].) These
characterizations are consistent with "temperature" being used as a measure
of the heat ("enthalpy") of reaction. This is not necessarily inappropriate if
the conditions of the measurement are specified adequately, or are
standardized in the art. The Specification does not, however, specify
particular conditions, including amounts of materials and reactor
characteristics, including reactor mass, extent of insulation, etc.
5
Appeal2017-009699
Application 13/485,657
Tonca discloses that "[h ]ydrogen gas can be produced from water by
contacting the water with a reactant compound comprising a suitable water-
reactive metal and an anti-passivation material; such a reaction is known as a
'water split reaction'." (Tonca col. 5, 11. 62---65.) In Tonca's words, "[t]he
anti-passivation material is a material that slows or prevents the passivation
of the metal, such as the metal's oxide." (Id. at col. 5, 1. 67---col. 6, 1. 2.)
Tonca explains that, "the anti-passivation material serves to prevent or slow
down the deposition of reaction products on the reactant metal surface that
tend to passivate the reactant metal and thereby inhibit the water-split
reaction." (Id. at 11. 2-8.)
Tonca further discloses, regarding the anti-passivation material, that
U.S. Pat. No. 6,582,676 (Chaklader)l 11J discloses a method of
producing hydrogen by reacting ... aluminum ... with water
in the presence of an effective amount of a catalyst at a pH of
between 4 and 10. The catalyst (promoter) is selected
to prevent or slow down deposition of the reaction products
on the metal that tend to passivate the metal.
(Tonca col. 1, 11. 48-54 (emphasis added).) Thus, it is clear that the materials
Tonca calls "anti-passivation materials" are also referred to in the art as
"catalysts" or "promoters."
Chaklader makes this point expressly:
Whereas Aluminum is the component which enters into
chemical reaction with water, the second nonmetallic
component of the system (referred to as 'catalyst' or
'additive') assists in preventing passivation of the Aluminum.
11 Asok Chandra Das Chaklader, Hydrogen generation from water split
reaction, U.S. Patent No. 6,582,676 B2 (2003) (hereinafter, "Chaklader").
6
Appeal2017-009699
Application 13/485,657
The water split reaction for the Aluminum/water system is as
follows:
2Al + 6H20---+ 2Al(OH)3 + 3H2 {9>pH>4} (2)
(Chaklader col. 3, 11. 58---65.)
In particular, Tonca teaches that the anti-passivation material can be
boehmite. (Tonca, col. 6, 11. 6-8.) Chaklader explains that boehmite is a
calcined (i.e., heated in air) aluminum monohydrate, AlOOH. (Chaklader
col. 8, 11. 48-50.) Chaklader describes the catalytic activity of boehmite in
the water-split reaction. (Chaklader, col. 16, 11. 8-35 (Example 6, reporting
reactions at temperatures between 40°C and 60°C; and Table 4 at col. 12,
11. 36-48, reporting the water temperature effect on hydrogen generation at
temperatures ranging between 30°C and 70°C).)
Tonca teaches that "[i]t is known that aluminum has a very high
affinity for oxygen, and that aluminum can be reacted with water molecules
to split the water molecules and release hydrogen according to the following
equation:
2Al (solid)+ 6H20 (liquid)>>> 2Al(OH)3 (solid)+3H2 (gas)
(Tonca, col. 6, 11. 20-25.)
Comparison of Tonca's reaction equation, Chaklader equation 2, and
the corrected reaction equation from the '657 Specification, shows the
equations have identical chemical starting materials and products. The
"catalyst" appearing in the '657 Specification reaction is not a reactant, as it
remains unchanged upon completion of the reaction. It is a fundamental and
well-known fact that catalysts increase the rate of a reaction by lowering the
activation energy, i.e., they provide a lower energy pathway for the reaction
to proceed. But catalysts do not shift the position of equilibrium of a
7
Appeal2017-009699
Application 13/485,657
reaction. 12 In particular, they do not change the products of the reaction
(including the distribution of products), thus they do not change the heat of
reaction, that is, the energy released as a result of the chemical reaction.
Thus, the heat of reaction associated with these three reaction equations is
identical. In particular, assuming arguendo that the heat reported as a
temperature range in the '657 Specification is a heat of reaction, each reaction
equation must have a "heat between approximately 15 °C and
approximately 280 °C" as disclosed by the '657 Specification and required by
appealed claim 10.
In the alternative, if the "heat" reported in the '657 Specification is
merely the temperature at which the reaction occurs, as Zhou appears to have
argued (seemingly inconsistently with the disclosure in the '657 Specification
at paragraph [0029]), Chaklader, in Example 6 and Table 4, would have
provided a reasonable expectation of conducting hydrogen generation
reactions using aluminum and boehmite in contact with water at temperatures
within the recited range of 15°C-280°C. Appellant has not challenged the
Examiner's conclusions regarding the combination of the teachings of Tonca
with those of Kindler.
Because we make findings not previously set forth during examination,
we designate our affirmance of the rejection of claim 10 a new ground of
rejection in order to provide Zhou with a full and fair opportunity to respond.
12 See, e.g., Robert L. Burwell, Jr., Catalysis, 3 McGraw-Hill Encyclopedia
of Science & Technology 298-299 (1992) ("If a reaction is in chemical
equilibrium under some fixed conditions, the addition of a catalyst cannot
change the position of equilibrium without violating the second law of
thermodynamics.").
8
Appeal2017-009699
Application 13/485,657
At the same time, we do not address the dependent claims, leaving that duty
to the Examiner, who, by virtue of his daily experience with this art, is better
positioned to determine whether the subject matter of those claims is
patentable in the first instance.
C. Order
It is ORDERED that the rejection of claims 10, 11, 13, 15, 16, 21,
and 30 under 35 U.S.C. § 103(a) in view of the combined teachings of Tonca
and Kindler is reversed.
It is FURTHER ORDERED that the rejection of claim 17 under
35 U.S.C. § 103(a) in view of the combined teachings of Tonca, Kindler and
Baker is reversed.
It is FURTHER ORDERED that Claim 10 is rejected under
35 U.S.C. § 103(a) in view of the combined teachings of Tonca, Chaklader,
and Kindler.
This decision contains a new ground of rejection.
37 C.F.R. § 41.52(a)(l) provides that "Appellant may file a single request for
rehearing within two months from the date of the original decision of the
Board." 37 C.F.R. § 41.50(b) provides that "[a] new ground of rejection
pursuant to this paragraph shall not be considered final for judicial review."
37 C.F.R. § 41.50(b) also provides that Appellant, WITHIN TWO MONTHS
FROM THE DATE OF THE DECISION, must exercise one of the following
two options with respect to the new ground of rejection to avoid termination
of the appeal as to the rejected claims:
(1) Reopen prosecution. Submit an appropriate amendment
of the claims so rejected or new Evidence relating to the claims
9
Appeal2017-009699
Application 13/485,657
so rejected, or both, and have the matter reconsidered by the
examiner, in which event the proceeding will be remanded to the
exammer ....
(2) Request rehearing. Request that the proceeding be
reheard under §41.52 by the Board upon the same Record ....
Should Appellant elect to prosecute further before the Examiner
pursuant to 3 7 C.F .R. § 41. 50(b )( 1 ), in order to preserve the right to seek
review under 35 U.S.C. §§ 141 or 145 with respect to the affirmed rejection,
the effective date of the affirmance is deferred until conclusion of the
prosecution before the Examiner unless, as a mere incident to the limited
prosecution, the affirmed rejection is overcome.
If Appellant elects prosecution before the Examiner and this does not
result in allowance of the application, abandonment or a second appeal, this
case should be returned to the Patent Trial and Appeal Board for final action
on the affirmed rejection, including any timely request for rehearing thereof.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
REVERSED; 37 C.F.R. § 41.50(b)
10
Application/Control No. Applicant(s)/Patent Under Patent
Appeal No.
Notice of References Cited
13/485,657
Examiner Art Unit
1725 Page 1 of 1
U.S. PATENT DOCUMENTS
*
Document Number Date
Country Code-Number-Kind Code MM-YYYY Name Classification
A US- 6582676 06-2003 Chaklader
B US-
c US-
D US-
E US-
F US-
G US-
H US-
I US-
J US-
K US-
L US-
M US-
FOREIGN PATENT DOCUMENTS
*
Document Number Date
Country Code-Number-Kind Code MM-YYYY Country Name Classification
N
0
p
Q
R
s
T
NON-PATENT DOCUMENTS
* Include as applicable: Author, Title Date, Publisher, Edition or Volume, Pertinent Pages)
u Catalysis, McGraw-Hill Encyclopedia 1992
v
w
x
*A copy of this reference is not being furnished with this Office action. (See MPEP § 707.05(a).)
Dates in MM-YYYY format are publication dates. Classifications may be US or foreign.
U.S. Patent and Trademark Office
PT0-892 (Rev. 01-2001) Notice of References Cited Part of Paper No.
(12) United States Patent
Chaklader
(54) HYDROGEN GENERATION FROM WATER
SPLIT REACTION
(75) Inventor: Asoke Chandra Das Chaklader,
Vancouver (CA)
(73) Assignee: The University of British Columbia,
Vancouver (CA)
( *) Notice: Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 124 days.
(21) Appl. No.: 09/778,091
(22) Filed: Feb. 7, 2001
( 65) Prior Publication Data
(63)
(51)
(52)
(58)
(56)
US 2002/0048548 Al Apr. 25, 2002
Related U.S. Application Data
Continuation-in-part of application No. 09/637,930, filed on
Aug. 14, 2000, now Pat. No. 6,440,385.
Int. c1.7 .............................. corn 3/02; corn 3/10
U.S. Cl. ..................................... 423/648.1; 423/657
Field of Search ............................... 423/648.1, 657
References Cited
U.S. PATENT DOCUMENTS
3,348,919 A
3,716,416 A
3,966,895 A
3,985,865 A
4,064,226 A
4,072,514 A
4,356,163 A
4,988,486 A
* 10/1967 Shumway ................... 423/657
2/1973 Adlhart .................... 136/86 B
6/1976 Wilhelm ................. 260/668 D
10/1976 Hohne ........................ 423/657
12/1977 Becker ....................... 423/657
2/1978 Suzuki ..................... 75/168 R
10/1982 Davidson .................... 423/657
1/1991 Harris et al. ................ 422/191
1000
I lllll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111
FR
GB
GB
GB
JP
US006582676B2
(10) Patent No.: US 6,582,676 B2
Jun.24,2003 (45) Date of Patent:
5,143,047 A
5,494,538 A
5,510,201 A
5,514,353 A
5,593,640 A
5,728,464 A
5,817,157 A
5,840,270 A
6,093,501 A
9/1992 Lee ............................ 126/263
2/1996 Kirillov et al. ............. 148/420
4/1996 Werth .......................... 429/17
5/1996 Adlhart ...................... 422/239
1/1997 Long et al. ................. 422/111
3/1998 Checketts ................... 428/403
10/1998 Checketts ...................... 48/61
11/1998 Werth ......................... 423/658
7/2000 Werth .......................... 429/17
FOREIGN PATENT DOCUMENTS
2658181
1378820
1420048
1496941
0216242
8/1991
12/1974
1/1976
1/1978
2/1992
OTHER PUBLICATIONS
0 417 279 Al EEC App = WO 90/09956 Mar. 20, 1991.
Search Report from Corresponding PCT Application No
PCT/CAOl/01115.
* cited by examiner
Primary Examiner-Stanley S. Silverman
Assistant Examiner-Maribel Medina
(74) Attorney, Agent, or Firm---C. A Rowley
(57) ABSTRACT
A method of producing Hydrogen by reacting a metal
selected from the group consisting of Aluminum (Al), Mag-
nesium (Mg), Silicon (Si) and Zinc (Zn) with water in the
presence of an effective amount of a catalyst at a pH of
between 4 and 10 to produce Hydrogen. The catalyst or other
additive is selected to prevent or slow down deposition of
the reaction products on the (impair reactions with the)
metal that tend to passivate the metal and thereby facilitates
the production of said Hydrogen.
24 Claims, 11 Drawing Sheets
-:cc Effect of the amount of gamma alumina on the total amount of hydrogen produced in one hour.
C> .... All data are normalized per gram of aluminum metal. - 800 CJ
~ ....
..c: ....
c: 600
"'C
Q)
CJ
:l
"'C 400 0 ....
ll..
c:
Q)
C> 200
0 ....
"'C
>.
J:
0
0 20 40 60 80
Calcined Boehmite Content in the Composite (wt.%)
0
•
1000 00 • ......._ Effect of the amount of gamma alumina on the total amount of hydrogen produced ~ --( one hour. ~
~
C> All data are normalized per gram of aluminum metal. ~
~
= ' 800 ~ (J
(J
~
....
.c ~
= ~ = .
600 c N ·- .. "
'C N Q
OJ Q
(J (.;.)
:J
'C 400
0 rJJ ....
=-Q. ~ ~
!"to c ~
(I) c
C) 200 ""'i
0 ~ ~ ....
'C
)\
I
0
0 20 40 60 80 ~ Cl1
Calcined Boehmite Content in the Composite (wt.%)
~
~
tit
~
N
~
~
Figure 1 '1 ~
o=
N
300 -------~--------"---------~--.
~ Effect of the reaction temperature on the total amount of hydrogen produced -<( in one hour. The additive (gamma alumina) amount is 20%.
~ 250 +--~A_lld_at_aa_ra_no_rm_a_li~_d_pe_rg_ra_mA_I.~~~~~--~~~~~
' u u
~ ..
~ 200~~~~~~~~--~~_,._~~~-i ,..
c: ·-
"CJ
~ 150+--~~~~~~~~-+-~~~~~_,
u
::J
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-c
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0 20
•
40 60 80
Reaction Temperature (deg. C)
Figure 2
0
•
00
•
~
= = .
500 .., ..... --···----.---................ , ... ,.,,,,.,,..,.,.,~,. .. ~••>w••-·--·~-•""'"'"'""""~······•·"'''"" __ ,,. ______ ,. ______ ,_._~'"'~--••-.,-·--··----•·•·-.
-
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Or
400
~ 8 300
o~
... c
Q. 0
c;
& ~ 200
0 G) ......
'C ... )\ .c
:c ~
.~ 100
0
Amount of hydrogen generated in 1 hr of aluminum-assisted water split reaction, as a
function of pH, for pure Al and Al with alumina additive (data normalized to 1g of Al based
on Tab. 4 and 5).
Mixed System: Al+20wt% Additive
D D D \
D
Additive Effect
Pure System: Al only"-i
0 2 4 6 8 10
pH
Figure 3
12
~
•
rt1
•
~
=
= .
~
rt1
~
\I
Ol
~
N
\I
~
'I
~
~
N
-<(
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u
u -"C
cu ..
~
cu
c:
cu
(!)
c:
cu
Cl e
"C
>a
:c
400
300
200
100
I Kinetics of hydrogen generation (cumulative curves) showing effects of various ceramic
additives in Al
I #"= . ~,tc~' L1 L-1
I ..
I ff JJii~ 1~GammaAlumina
~Alpha Alumina
~Aluminum Trihydrate
--e- Boehmite
I
I
0
....
---·
0 20 40 60 80
Time (min)
Figure 4
d •
\JJ.
•
~
~ ......
~ = ......
~
= ?
N
~,J;;..
N c c
~
'Jl
=-~
~ .....
,J;;..
0 .....,
'"""' '"""'
e
\JJ.
O'I
'&.
~
N
°' ""-l O'I
~
N
..... BOO Effect of the r~ion tempe;ature on the tolal a~ hydrogen pr?duced in o~e hou;,-i
- for 10%, 20%, 30% and 40% amount of gamma-alumina (?DOC calcined boehm1te) I
~ addiijve .All dala are normalized per gram of aluminum melal. 1
~ I
~ • -----. 40% I
~ 400~~~~~~~--,~~~...__~~~~~
120%
• 10%
0-+--~~~----~~~~-r--~~~~
20 40 60
Reaction Temperature {deg.C)
Figure 5
80
d
•
r/1
•
~
= = .
\11
=-~
~
~
!JI
0
~
~
~
1800 --~-----------
Effect of the amount of the alumina additive (derived form calcined boehmite 8700)
~
<( compared to alumina (corundum) on the total amount of hydrogen produced in one hour.
~
1500
All data are normalized per gram of aluminum metal.
-.......
(.)
(.)
........
'- Corundum-Coarse
.c 1200 -1---------------------1
"" (Alpha-Alumfa)
c ·-,,
G> 900 -------------.-:--------.-------!
(.)
:J ,,
0
~ 600~~~~~~--~~~~~~--~~
c
G>
Cl
Gamma-Alumina
e 300-1--~--~----~___._~~~~~~~~~~ ,,
>-
I
0 20 40 60 80 100
Additive Content in the Composite (wt.%)
Figure 6
~
•
rt1
•
~
=
= .
d
•
1000 r/1 •
__....,
~ - Effect of the amount of carbon (lamp-black) additive to Al on the total amount of hydrogen <( ~
produced in one hour. All data are normalized per gram of aluminum metal. ~ en ~
T- = ........ 800 ~ (J
(J
-......
...
.c ~
= T- = .
c 600 N .i;. ·- "
tl N = G) = (J "' ::l
-a 400 0 \11 s..
=-c. ~ ~
~
c '-l
Q) 0
en 200 ~ 0 ~ ~ ...
-a
)\
I
0 20 40 60 80
Carbon Additive Content in the Composite (wt.%)
Figure 7
d
•
1200 r/1 •
,,,,... Effects of the amount of carbon (lamp-black) vs. alumina (corundum) additives ~ - ~ pH>4} (2) 65
system, or replenished through abundant distribution system
in place). As Aluminum, Aluminum oxide and Aluminum
hydroxide are the safest materials known to humanity (e.g. Broadly the present invention relates to a method of
producing Hydrogen by reacting a metal selected from the are commonly used in food, drug, cosmetics etc. products),
US 6,582,676 B2
5
the novel process promises to be safe and manageable by
simple means. The amounts of Hydrogen produced and
consumed can be balanced, avoiding necessity of on-board
storage of excessive amount of Hydrogen, which can
become dangerous in some critical situations, e.g. container 5
leakage.
BRIEF DESCRIPTION OF DRAWINGS
6
electrolysis of alumina (to produce Al) is performed using
hydroelectric or other renewable form of energy.
The principal discovery disclosed in the present invention
is that the pH remains substantially neutral i.e. pH 4 to 10
and that the reaction (2) is sustained, i.e. passivation layer of
reaction products does not appear to hinder the reaction, if
the reacting Aluminum metal is in contact with externally
supplied nonmetal (ceramic) such as Aluminum oxide(s) or
hydroxide(s). Thus, a composite material comprising Further features objects and advantages will be evident
from the following detailed description of the present inven-
tion taken in conjunction with the accompanying drawings
which illustrate specific embodiments of the invention are
not intended to limit the scope of the invention in any way.
FIGS. 1, 2 and 3 present the amount of Hydrogen, in cubic
centimeters (cc), produced in 1 hr in the water split reaction
out of Aluminum+Alumina and Aluminum hydroxide com-
posite systems, as a function of additive amount, reaction
temperature, and pH, respectively.
10 mechanical mixture of Aluminum metal (Al) and Aluminum
oxide(s) or hydroxide(s), when submerged in water, con-
tinuously produces Hydrogen gas. The reaction proceeds for
the mass ratio of Al to the oxide(s) or hydroxide(s) varying
over the whole range, from a few percent to up to 99% of the
FIG. 4 illustrates several typical curves of Hydrogen
accumulation over the 1 hr reaction time, for the experi-
ments included in Table 1.
15 catalyst (or additive(s)). Similarly, the reaction proceeds in
a wide range of acidity/alkalinity (pH) of water, e.g.
ll>pH>2, and water temperature, e.g. from about 10° C. to
90° C. Although the reaction proceeds faster at elevated
temperatures, water acidity/alkalinity in the range 9>pH>4
FIG. 5 is a plot showing the effect of reaction temperature
20 has relatively weak effect on the reaction rate. The phenom-
enon of production of Hydrogen from Aluminum and water
using a water split reaction in the presence of a catalysts has
been demonstrated reproducibly, as illustrated in the follow-
on total Hydrogen produced in 1 hour for 10%, 20% 30%
and 40% gamma-alumina normalized per gram of Al metal. 25
FIG. 6 is a plot showing the effect of the amount of
gamma alumina additive derived from calcined Boehmite
compared to alpha Alumina (corundum) on total Hydrogen
produced in 1 hour normalized per gram of Al metal.
30
FIG. 7 is a plot showing the effect of the amount of carbon
(Lampblack) to Al on total Hydrogen produced in 1 hour-
normalized per gram of Al metal.
FIG. 8 is a plot showing the effect of the amount of carbon
(Lampblack) vs. alumina Al2 0 3 (corundum) additives to Al 35
on total Hydrogen produced-normalized per gram of Al
metal.
FIG. 9 is a plot showing the effect of Carbon (Lampblack)
and Al2 0 3 (corundum) additive in Al-(C+Al2 0 3) System
on total Hydrogen produced-normalized per gram of Al 40
metal, (carbon content constant at 20% ).
FIG. 10 is a plot showing the effect of carbon
(Lampblack) and Al2 0 3 (corundum) additive in Al---(C+
Al2 0 3 ) System on total Hydrogen produced-normalized per
gram of Al metal, (corundum content constant at 30%).
FIG. 11 is a plot showing the effectiveness of an magne-
sium (Mg) magnesium oxide (MgO) system for generating
hydrogen (H2 ) using different ratios of Mg to MgO.
DETAILED DESCRIPTION OF INVENTION
45
50
One of the key features of the present invention is that the
reactant system is able to sustain the Aluminum-assisted
water split reaction, equation (2), in neutral, or close to
neutral conditions, i.e. in the range of a pH 4 to 10 preferably 55
pH 5 to 9.
If tap water is used (as in plurality of experiments
described below) the only products of reaction (2) (i.e. after
completion of the reaction) are Aluminum oxide(s), Alumi-
num hydroxide(s) and Hydrogen. Aluminum oxide and 60
hydroxide are readily recyclable back to Aluminum metal
through the well-known electrolysis process. The Hydrogen,
thus generated, can be subsequently oxidized to water in the
fuel cell. The resulting water can be feed back to sustain the
water split reaction (2). The life-cycle loop for Hydrogen 65
generation through Aluminum assisted water split is thus
closed with no impact on the environment, especially if
ing figures and examples.
The principal observations are summarized as follows:
1. H2 is generated in Al/additive mixtures exposed to tap
water
2. existence of a triple point where water, Al and additive
are all in contact, appears a necessary condition for the
water split reaction to start and continue
3. The most effective additives appear to be oxides, in
particular Aluminum oxides, and carbon
4. The additives, e.g. oxides or carbon, must be pulverized
with Al through intensive mixing; in this process the
additives are dispersed through heavily deformed Al
matrix
5. The oxides effective in "catalyzing" the Al-assisted
water split reaction, in order of effectiveness, include
alumina (various polymorphs), Aluminum hydroxides
but also alumina-silicates (ball clay, china clay),
magnesia, and others.
6. Carbonates (calcium) and hydroxides (calcium),
although they do produce some H2 in contact with
Al+water, the gas amounts are relatively small (less
than a third) as compared to the alumina powders
7. The reaction is temperature-sensitive (in T=20 ... 70°
C. range), but not particularly pH sensitive (in pH
range=4-9)
8. The reaction is particularly sensitive to Al2 0 3 content,
the H2 yield per unit Al increasing to almost 100% (all
Al reacted) for Al2 0 3 content increasing up to 95 wt%.
9. Pulverizing Al powder with water-soluble polyethylene
glycol (PEG) also seems to produce significant water-
split reaction (H2 produced is about half of that
obtained using alumina additive), with yield indepen-
dent on the content of PEG. However, adding to water
PEG slows the reaction if oxide catalysts are used.
10. Non-Aluminum systems, i.e. metal mixed with its
oxide, although do produce measurable amount of
Hydrogen, are less effective in assisting in water split.
Out of many tested, only Si-Si02 and Zn-ZnO in
water seem to induce some H2 generation
Pulverizing Al+additive in closed environment causes
"Mechanical Alloying", i.e. blending/encapsulation of the
components, with multiple intimate interfaces between Al
US 6,582,676 B2
7
and the additive. As limited amount of oxygen is available
in the air-tight mill volume, the surface of Al remains
substantially free of oxides during milling. This likely
returns to the passivated Al state (i.e. film of oxide/
hydroxide on the surface) once exposed to air after milling. 5
This can be prevented through coverage of the surface of Al
particles with secondary additive phases, e.g. particles of
ceramic, such as alumina or carbon, or polymer, such as
polyethylene glycol (water-soluble polymer seems particu-
larly attractive as it will expose fresh Al surface upon
10
dissolution in water).
PEG (polyethylene glycol) pulverized with Al, through
coating freshly-created surface of Al, prevents its
re-oxidation during transfer from the mill to water. This
effect is achieved even for relatively small, e.g. few wt % of
15
PEG; additional amount of PEG just builds thicker layer on
Al; thus the effect is independent on PEG content. Once in
water, PEG dissolves and exposes relatively large area of
non-passivated Al to reaction. Effectively PEG acts in a
similar "enabling" way to expose fresh Al. It is then per-
20
ceived as very effective method for ionizing Al especially if
accompanied with oxide additive (i.e. alumina) which would
preferentially accept precipitating Al(OHh This effect is
reinforced if both PEG and alumina are dispersed through-
out a volume of Al particles.
25
Extensive experiments were performed to test the feasi-
bility of Hydrogen generation from water, and to identify the
factors affecting this process. Two critical parameters moni-
tored were (i) total volume of H2 generated per unit weight
of the Aluminum (i.e. conversion efficiency) and (ii) rate of
30
H2 release. The factors affecting these two parameters have
been identified as above described to be as follows:
(a) Type and concentration of the component materials, in
particular Aluminum and ceramic additives
8
Hydrogen generation from water using Al metal and
alpha-alumina (a-Al2 0 3 ), carbon (C) (lampblack) and other
ceramic materials, was investigated to determine if other
inexpensive catalysts similar alpha-alumina could be used.
The purpose of using carbon was to test if the mixtures
(Al+C) could be used for generating Hydrogen.
Additionally, the carbon addition should improve the elec-
trical conductivity of the composites. The effect of the
electric field on the composite pellets in generating Hydro-
gen may be effective.
Other composites tested included Magnesium (Mg) and
Magnesium Oxide (MgO), Al and Mg and Al2 0 3 , Al and
organic salt (water soluble) and other metal and oxide
systems.
It has been found that both alpha-alumina and carbon
(with Al) are very effective in generating Hydrogen, and as
good as gamma-alumina (y-Al2 0 3 ) derived from calcined
Boehmite. It appears that Al+C+a-Al2 0 3 systems are very
good in generating Hydrogen from water. There are other
systems with Al, which can produce Hydrogen from water,
but these systems are not attractive as the final products are
not easily recyclable. Mg-MgO systems are not as effective
as Al+a-Al2 0 3 (or Al+C) systems in generating Hydrogen
from water.
The following is description of the experimental programs
that tested the above variables in relationship to the use of
metal-ceramic composites for water split reaction to produce
Hydrogen.
All samples used to produce the data in FIGS. 1-3 were
produced in the same way, i.e. boehmite (calcined at 700°
C.) was combined with appropriate amount of Al powder
(99% Al, 80 µm average particle size), vibro-milled for 10
min, and pelletized at 5000 psi pressure. High-intensity
vibromill, referred to as Spex mill, was used. For FIG. 1 the
(b) Mixing, grinding and pelletization methods to bring
the component materials (i.e. Aluminum and ceramic
additives) to physical contact
(c) Reaction temperature
35 constants include T=50° C. and pH=6.5. For FIG. 2 the
constants include amount of additive=20 wt%, and pH=6.5.
For FIG. 3 the constants include T=50° C. and amount of
additive in mixed system 20 wt %.
( d) Water acidity /alkalinity (pH)
Al metal with alpha-alumina, gamma-alumina, carbon 40
(lampblack), mixtures of a-alumina and carbon, and poly-
ethylene glycol (a water soluble organic compound) were
used to determine the water split reaction rate and conver-
sion efficiency. Attempts were also made to test other
ceramic materials, such as clays, CaC03 , Si02 etc., with Al 45
to get water split reaction. Further tests were made using
other metals and their oxide systems, such as Fe-Fe3 0 4 ,
Cu-Cu20, Ni-NiO, Mg-MgO, Si-Si02 , Ti-Ti02 , and
Zn-ZnO, to initiate the water split reaction.
The results of these tests can be summarized as follows. 50
The systems containing alpha-alumina and carbon with Al
are as effective as gamma-alumina+Al system in generating
Hydrogen gas. A combination of alpha alumina+carbon with
(a) Type and Concentration of the Component Materials
In one set of test Aluminum powders having five different
average particle sizes of 10, 44, 60, 80 and >200 microns
(um) were used. These powders were of nominal purity i.e.,
-99% pure Al, except the 60 µm powder, which was a
reagent grade (99.9% Al). Although the nominal particle size
was quoted by the supplier, it is noted that there is a large
variation in each size grade. The largest grade powder had
very coarse particles, -80% larger than 200 µm. The addi-
tives were Aluminum oxides produced by cacining (i.e.
heating in air) Aluminum hydroxides. Both monohydrate
(AlOOH, known as boehmite) and trihydrate of Aluminum
[Al(OHh] were used for these tests. Several grades of
commercially available Aluminum oxide were also utilized.
There are different crystallographic forms of Aluminum
oxides, such as a, y, etc. Both a and y Aluminum oxides Al is better than any system tested so far. There is an almost
linear relationship with the amount of Hydrogen generated
and the catalyst concentration, leading to almost full con-
version with 95% catalyst (with respect to the possible
theoretical amount, which is about 1.2 liters per gram of Al).
55 were used in these tests, but there is no doubt that other
forms Aluminum oxides when ground and mixed with
Aluminum metal powder will produce Hydrogen gas when
added to water
All the other (i.e. in addition to Aluminum oxide and
hydroxide) ceramic materials with Al generated some 60
Hydrogen from water. Of these the best results are with ball
clay, which produced -2/3 of the amount produced with
alumina+Al system. However, this system is not attractive in
terms of recyclability. In terms of other metal-oxide systems,
a small amount (10%-15% of theoretical amount) of Hydro- 65
gen generation was encountered with Si-Si02 and
Zn-ZnO systems.
Effect of the Type of Ceramic Additive
The effects of different type of additives used with Al are
summarized in Table 1, in terms of the amount of H2
released from the reactor after 1 hr of reaction, the maximum
rate of Hydrogen release, and the time to the moment of
maximum rate of Hydrogen release (measured from intro-
duction of the metal-ceramic composite pellet into the
water). All samples were Spex Milled for 10 min, with 30 wt
% additive ceramic powder (the balance 70 wt% was the 80
US 6,582,676 B2
9 10
between 5.8 and 7.5. The results are shown in Table 2 and
also plotted in FIG. 5. All data are normalized as the volume
of generated Hydrogen per one gram of Aluminum metal.
There is a linear correlation of Hydrogen generation with the
µm average particle size Al powder). The mixed powders
were pelletized under 8000 psi. The pellets weigh about 1 g
and the testing water temperature was 50° C. Tests in water
are carried out at the pH range 5.8 to 7.5 (typical fluctuations
of tap water).
TABLE 1
5 increase in additive. As the additive concentration is
increased in the mixture more Hydrogen gas is generated,
per unit quantity of metal (Al).
Additive
in Al
Gamma
Alumina
Effect of type of additive on Hydrogen generation
through Aluminum assisted water split reaction.
H2 release after Max. Rate of H2 Time to max Rate
1 hr (cc/g Al) release (cc/min) of H2 Rel. (min)
342 17 10
Alpha Alumina 320 25 8
Aluminum 146 5 16
Trihydrate
Boehmite 194 7 16
10
15
"Gamma Alumina" is produced from Boehmite by cal-
20
cining at 700° C. "Boehmite" stands for Aluminum
monohydrate, which was supplied by Condea Chemicals.
"Boehmite" in the table is Aluminum monohydrate, and
used as-received state. Alpha Alumina is obtained from
Alcan, which is supplied as a free flowing powder. Alumi-
num Trihydrate is a synthetic Aluminum hydroxide supplied 25
by Alcoa. Effectively, all the tested additives are alumina or
hydrated alumina (Aluminum hydroxide). The kinetics of
H2 generation data for various additives are also illustrated
in FIG. 4.
It can be easily shown from equation (2) that one gram of 30
Aluminum metal on 15 complete conversion to Aluminum
hydroxide should produce 1.24 liters (1,240 cc) of Hydrogen
gas. On that basis, both Gamma and Alpha alumina pro-
duced about 25-30% of the theoretical amount of the
Hydrogen. This means about 25-30% of the available Al is 35
consumed for two alumina additives. For the other two
additives in the figure, the fraction Al consumed is in the
order of 10 to 15%.
TABLE 2
Effect of the amount of additive on Hydrogen
generation through Aluminum assisted water split reaction.
Amount of H2 release
Additive after 1 hr
(wt.%) (cc/1 g Al)
5 7
10 105
15 125
20 206
30 245
40 320
50 515
75 650
90 870
(b) Mixing, Grinding and Pelletization Methods
The goal of mixing/milling of the component powders
was to produce a homogenous composite with multiple
interfaces including the metal and ceramic in contact. In this
experimental program the following methods of mixing the
metallic component (powder) with ceramic component
(powder) have been tried: hand grinding i.e., mixing in a
mortar-pestle, ball milling and high impact mixing and
grinding (Spex milling). Another possible method of high
energy mixing and grinding is attrition milling. The mixing/
milling may be accomplished in a batch process, i.e. milled
powders pelletized and transferred to water-split reactor, or
in a continuous process, wherein water and the reactant
powders are fed to the mill and the reaction products
(Hydrogen and hydroxides) continuously released from the All the tested aluminas, which have a tendency to hydrate
in water, activate the water split reaction to generate Hydro-
gen in the Aluminum-assisted water split reaction. Those
aluminas, which were already partially or filly hydrated, e.g.
because of low calcinations temperature (or no calcinations)
were less effective in assisting the water split reaction,
however, these still produced Hydrogen from water. The
most effective additive appears to be the boehmite calcined
at 700° C. and alpha alumina.
40 mill. The batch process is experimentally simpler and there-
fore most disclosed experiments were completed in such
process. The continuous process is more technologically
challenging, but better allows achievement of near 100%
reaction yield.
45 The Effects
Aluminum Metal Particle Size Effect
It has been observed that after Spex milling all Aluminum
particles larger than about 30 µm got flattened and well 50
mixed through repeated plastic deformation with the
ceramic additive. Eventually, the composite particles
agglomerated to similar sizes, in the range of 70 to 100 µm.
There was no substantial reduction of the original size of the
particles. For the largest (>200 µm) particles there is fiat- 55
tening observed but not much mixing with the ceramic
powder. That is the reason why the amount of Hydrogen
generated is similar for all particle sizes up to 80 µm. And
there is less production of Hydrogen with largest Aluminum
> 200 µm particles. It is believed that Particle sizes in the 60
range of about 0.01 to 1000 µm should be equally effective.
Effect of the Concentration of Ceramic Additive
For these tests Aluminum metal having the average par-
ticle size 80 µm was used along with boehmite calcined at
700° C. as additive. All mixtures were Spex-milled for 10 65
min and pelletized under 5000 psi to about 1 g pellet. The
water reaction tests were carried out at 50° C. at a pH
Type of Mixing Effects
In any mechanical mixing (which involves also grinding)
it is expected that the particle size of the initial components
in the mixture will have an influence on final state of the
mixed powder, unless the mixing effect eliminates the vari-
ability of the initial particle size of powder. It is also
expected that the type of equipment used for such mechani-
cal mixing will have a bearing on the final state of the mixed
powder. Hand mixing and grinding Aluminum metal and
oxide powders in a mortar-pestle is laborious and produced
Hydrogen in amount less than 50% of that obtained from
using the mixed powder from the Spex mill. Ball milling
using alumina balls was also time consuming as it took a few
hours to mix the composite powder also at least 50 grams of
powder had to be used per charge. Spex milling, which is
high impact mixing/grinding with alumina balls, was used in
almost all experimental tests.
In other tests aluminum metal was melted and mixed with
the solid additive powder, such as aluminum oxide. This mix
was solidified to form porous compacts and subjected to
water test to generate hydrogen. This method of mixing of
the two components was found to be similar to mechanical
US 6,582,676 B2
11 12
tinuously. This assessment is supported by the observation
that regrinding continues to generate more and more hydro-
gen gas from the same pellet (see the section on Regrinding
Effect).
m1xmg, in terms of generating hydrogen from water.
Therefore, mixing of aluminum metal in solid or liquid state
with the additives and subsequently making porous com-
pacts or loose powders are equally effective in generating
hydrogen from water. 5 Pelletization
Effect of Time of Mixing
The effect of time of mixing in the Spex mill is shown in
Table 3. All samples are Spex milled with alumina balls with
20 wt % boehmite additive (this is a boehmite, which was
supplied by Alcoa and identified as Baymal) calcined at 700° 10
C. The water temperature was 50° C. and pH was in the
range 5.8 to 7.5. After about 10 minutes of milling no effect
of longer milling time can be seen on the Hydrogen release
from water.
For easy handling of the composite powder, the mixed
powder was pelletized into either one gram or two grams
pellets. These were about 0.5 inch (1.25 cm) in diameter and
pelletized under either 5000 or 8000 psi. Pelletization has
both advantage and disadvantage. For example, it is easy to
insert a pellet inside the reactor full of water, which has to
be enclosed to determine the amount of gas released. On the
other hand, pressing the powder in a die made the pellet
dense which restricted water penetration into the pellet for
TABLE 3
Mixing time effect on Hydrogen generation
through Aluminum assisted water split reaction.
15 water split reaction to take place. Thus, it is noted that more
the pressure applied on the die during pelletization, less the
amount of Hydrogen gas produce under identical testing
conditions.
Mixing Time (min)
H2 release after
1 hr (cc/1 g Al)
20
(c) Reaction Temperature
It is obvious for those skilled in the art that the water split
reaction will progress faster at higher temperatures. The
objective of this testing program was to determine the
increase of Hydrogen release from Aluminum-ceramic com-
posites exposed to water. All samples prepared using 80 µm
5
10
15
20
30
Regrinding Effect
178
240
225
250
246
25 Al powder were Spex-milled for 10 min with 20 wt %
gamma alumina All specimens weighing -1 g were pressed
into pellets under 5000 psi. The water temperature varied
from 30° C. to 70° C. and pH was maintained in the range
The Aluminum-assisted water split reaction leads to pre-
cipitation of Aluminum hydroxide, according to reaction (2). 30
The way this non-soluble product of reaction distributes
throughout the system affects the reaction progress. For Al
only reacting with water, the reaction products precipitate on
5.8 to 7.5 (tap water).
The effects of reaction temperature on Al-assisted water
split reaction are compiled in Table 4, and FIG. 2. The
amount of Hydrogen gas generated is normalized as per
gram of Aluminum metal. The temperature has a significant
effect on the generation of Hydrogen. The increase becomes Al surface, and rapidly form a passivation layer which stops
any further reaction (this is why Al does not substantially
corrode under normal conditions). As disclosed in the
present invention, the Al-ceramic composites do not passi-
vate through substantial portion of the water split reaction.
35 less significant above 600 C.
It is anticipated that the reaction products (hydroxides)
preferentially nucleate and deposit on the ceramic additives 40
(e.g. alumina) supplied to the system through composing
with Al, and/or are ejected to the surrounding liquid (water).
As the reaction proceeds however, the reaction rate is slowed
down (as measured through Hydrogen release rate), and
eventually the reaction ceases. It is anticipated that the 45
buildup of the reaction products, albeit on the pre-existing
ceramic additives, eventually screens access of water to the
fresh Al surface. In order to test this hypothesis, all the solids
(i.e. the products and remaining reactant-Al) were
re-ground for 10 min after the initial 1 hr of reaction, to 50
expose the unreacted Al. The experimental conditions were
the same as that used for the effect of mixing time. The water
split reaction with the original pellet generated 14 7 cc of
Hydrogen (per 1 g of Al) after 1 hr reaction. The remaining
solids were re-ground and exposed to water again to addi- 55
tionally release 226 cc of Hydrogen (per 1 g of Al). The
solids remaining from this second reaction were re-ground
once again and the test was repeated. This last test generated
further 368 cc of Hydrogen (per 1 g of Al). It is therefore
observed that after each successive grinding of the same 60
pellet more Hydrogen gas can be produced. This means that
if grinding during the reaction with water can expose fresh
clean surface of Aluminum particles, more Hydrogen can be
generated, until all Aluminum is consumed. This is impor-
tant to note that a method of continuous grinding while 65
feeding water and powder of Al and/or Al+additive in a
reactor may provide a way to produce Hydrogen gas con-
TABLE 4
Water temperature effect on Hydrogen generation
in Aluminum assisted water split reaction.
Water Temperature (° C.)
30
40
50
60
70
(d) Water Acidity/Alkalinity
H2 release after
1 hr (cc/1 g Al)
20
110
185
220
224
It is obvious for those skilled in the art that reactivity of
Aluminum depends on acidity/alkalinity of water. In
particular, it is known that pure Al will corrode in very acidic
(pHll) environments, with
release of Hydrogen. It is also known that Al is practically
immune to water in intermediate range of acidity/alkalinity
close to neutral ( 4ll the total amount of Hydrogen formed is
increased. This shows that the caustic solution starts to
corrode the layer of hydroxide formed on the metal surface.
The same phenomenon occurs with pure Aluminum metal,
as shown in later experiments, refer to the following section, 10
Table 6 and FIG. 3. In all tests it was noted that pH value of
the water slightly increased (by -1.0 pH) at the end of the
reaction, especially in the range of 5.5 to 9.5. These results
are compared with pure Aluminum metal (80 µm particles)
fabricated under identical conditions (but without the 15
additive), in FIG. 3.
TABLE 5
14
Subsequently a pellet was produced from the same powder
under 8000 psi and exposed to water at 50° C. Finally, the
same powder was Spex-milled for 10 min, pelletized and
exposed to water at 50° C. In addition, similar experiments
were repeated where pH of the water was changed with
caustic soda to "highly caustic" conditions at pH=ll.5-12
and also made acidic adding HCl in water to lower the pH
down to 1.5. The data are compiled in Table 6, and also
included in FIG. 3.
The "as received" Aluminum powder does not produce
any measurable amount of Hydrogen in contact with neutral
pH water. Although milling the same powder seems to
expose some of the passivated Al surface to make it avail-
able for the reaction, the passivation film is quickly restored,
leading to very small release of Hydrogen from this system
The caustic conditions do cause substantial reaction with
pure Al, as expected. These results, together with the data
from Table 5, are mapped in FIG. 3 to illustrate the effect of
alumina additive on water split reaction in a range of pH
Water pH effect on Hydrogen generation
in Aluminum assisted water split reaction. 20 values from 1.5 to 12.0. Between pH 3 to 10, with alumina
additive about 15 to 18% of the available Aluminum metal
H2 release after
Water pH 1 hr (cc/1 g Al)
1.5 170
2.3 175
3.7 182
4.7 198
5.5 197
6.5 176
9.5 170
10.5 178
11.0 198
11.5 333
12.0 450
TABLE 6
Water pH Effect on pure Al (80 µm) at 50° C..
Powder H2 release after
Condition Water pH 1 hr (cc/1 g Al)
Milled & 1.5 20
Pressed
Powder
Milled & 3.5 16
Pressed
Powder
Loose 7.0 No gas (0 cc)
Powder "Neutral"
As-received
Pressed 7.0 No gas (0 cc)
Powder "Neutral"
As-received
Milled & 7.0 20
Pressed "Neutral"
Powder
Loose 11.5 113
Powder "Highly Caustic"
As-received
Milled & 11.5 160
Pressed "Highly Caustic"
Powder
Pressed 12.0 267
Powder "Highly Caustic"
As-received
Water Acidity/Alkalinity Effects for Pure Al Powders
In order to distinguish between the role of Aluminum
oxide blended with Al, and pure Al, in producing Hydrogen
from water, a series of experiments were carried out with the
Al powder itself. The loose 80 µm powder, as received, was
added to water at 50° C. at pH= 7 ("neutral conditions").
was consumed generating Hydrogen gas.
Summary of the Effects of the above Variables an
2s Al-Assisted Water Split Reaction
In summary, it has been proven beyond doubt that in
every experimental tests that Hydrogen is generated when
the metal-ceramic powder, either in the pelletized form or as
loose powder, is submerged in water, both at ambient
30 temperature (-20° C.) or at elevated temperature up to 90°
C., at neutral or close to neutral pH. The necessary condition
for the reaction to progress at neutral or close to neutral pH
is that the Aluminum and ceramic additive are in physical
contact during the reaction.
35
40
45
50
55
The rate of generation of gas and the total amount of gas
produced depend on several factors:
1. The maximum rate of gas release depends on (i) nature of
milling (ii) type of ceramic additive (iii) temperature of
reaction and (iv) pH of the water. The total amount of gas
release does not vary significantly with different type of
alumina ceramic additive, produced from different Alu-
minum hydroxides, (or Aluminum hydroxide).
2. Temperature has a significant effect both on the rate of H2
generation and the total amount of the gas produced.
3. pH has a strong effect on both the rate of gas release and
the total amount of H2 produced. However, below pH=lO
the effect is not noticeable. It has been known that both
caustic soda and H Cl attack and corrode Aluminum metal
producing Hydrogen gas. Both caustic soda and HCl is
dangerous to human health and damaging to environment.
4. The key feature of the investigated systems is the ability
to generate substantial amount of Hydrogen through water
split reaction at neutral pH (pH=6-7).
FURTHER EXAMPLES OF SPECIFIC
EMBODIMENTS OF THE INVENTION
The following examples clearly illustrate the specific
embodiments of the invention, but should not be construed
60 as restricting the spirit or scope of the invention in any way.
These example processes to produce Hydrogen in
Al-assisted water split reaction used Al powder blended with
variety of ceramic powders, generally aluminium oxide or
hydroxide, in variety of forms and morphologies, as
65 described in the preceding sections. The blending method is
critical to initiate and sustain the water split reaction. The
high-energy blending techniques, which produce multiple
US 6,582,676 B2
15
metal-ceramic interfaces, are more effective. The principal
process variables included mass ratio of the Al to the
ceramic, methods and time of blending the powders, tem-
perature and pH of reaction environment. Reference tests
were performed with the separate powders of Al and
ceramic, in a variety of environments. The principal param-
eter measured in all the tests was the total amount of
Hydrogen (cc) released after 1 hr of reaction, normalized to
16
particle, 0.4 g) was Spex-milled for 10 min., pelletized at
8000 psi and the pellet dropped to tap water at approxi-
mately pH=6 and T=50° C. The total amount of Hydrogen
released from the reactor after 1 hr was 200 cc, equivalent
5 to 125 cc/1 g of Al.
Example 6
Water-split Reaction for the Composite System: Al-
Calcined Boehmite
The Al powder (99% Al, 80 µm average particle size, 1.6
1 g of Al reactant. Additionally, accumulation of Hydrogen
during the 1 hr reaction was monitored in short time inter- 10
vals (i.e. 1 min) to determine variations in the reaction rates.
These data are provided in the following examples, and
illustrated in FIGS. 1-4. In each of these case the experiment
represented in FIGS. 1 through 4 reacted only part of the
available Al from the total Al in the pellets. 15 g), and AlOOH powder calcined at 700° C. (0.4 g) was
Spex-milled for 10 min, pelletized at 5000 psi and the pellet
dropped to tap water at approximately pH=6 and T=50° C.
The total amount of Hydrogen released from the reactor
Example 1
Water-split Reaction for the Reference System: Al
Powder Only
The Al powder (99% Al, 80 µm average particle size) was
pelletized at 8000 psi and the 1 g pellet dropped to tap water
at approximately pH=6 and T=50° C. There was no Hydro-
gen generation after 1 hr test.
Example 2
Water-split Reaction for the Reference System: Al
Powder Only
The Al powder (99% Al, 80 µm average particle size) was
Spex-milled for 15 min., pelletized at 8000 psi and the 1 g
pellet dropped to tap water at approximately pH=6 and
T=50° C. The total amount of Hydrogen released from the
reactor after 1 hr was 10 cc per 1 g Al.
Example 3
Water-split Reaction for the Reference System:
Oxidized Al Powder
20
after 1 hr was 296 cc, equivalent to 185 cc/1 g of Al. By
decreasing the temperature to 40° C., the H2 yield was 110
cc/1 g of Al, whereas at 60° C., the H2 yield was 220 cc/1
g of Al. If the amount of Al in the pellet was 1 g and amount
of calcined boehmite in the pellet was 1 g (50 wt%), the H2
25 yield was 515 cc/1 g of Al, for the T=50° C. bath. If the
amount of Al in the pellet was 0.5 g and amount of calcined
boehmite in the pellet was 1.5 g (75 wt%), the H2 yield was
650 cc/1 g of Al, for the T =50° C. bath If the amount of Al
in the pellet was further decreased to 10% of the total
30
amount of the composite (calcined boehmite in the pellet is
90 wt % ), the H2 yield was 870 cc/1 g of Al, for the T =50°
C. bath. The results given in Example #6 show the effect of
temperature and also of concentration on the Hydrogen
35 generation. The results are shown Tables 2 and 4.
Example 7
40
The Al powder (initially 99% Al, 80 µm average particle
size) was partially oxidized for 72 hr, which resulted in
0.05% weight increase due to formation of Aluminum oxide
layer on its surface. The partially oxidized powder was
Spex-milled for 15 min, pelletized at 8000 psi and the 1 g 45
pellet dropped to tap water at approximately pH=6 and
T=50° C. The total amount of Hydrogen released from the
reactor after 1 hr was 7 cc per 1 g Al.
Experimental Tests and Results with a-Al2 0 3 +
Aluminum
For these tests a very easily available and low-cost
powder alpha alumina powder (supplied by Alcan Alumi-
num Co.), was used. This type of powder is typically used
as refractory material for furnace insulation and is also one
of the main materials in Aluminum smelters for the produc-
tion of Aluminum metal. The powders were coarse (>50 µm
Example 4
Water-split Reaction for the Composite System:
Mixed Al+Al2 0 3
The Al powder (99% Al, 80 µm average particle size, 1.6
g), and Al2 0 3 powder (alpha-alumina, 0.2 µm average
particle size, 0.4 g) was loosely mixed without generation of
multiple contacts between metal and ceramic, for 10 min.,
pelletized at 8000 psi and the pellet dropped to tap water at
approximately pH=6 and T=50° C. There was no Hydrogen
generation after 1 hr test.
Example 5
Water-split Reaction for the Composite System:
Milled Al-Al2 0 3
The Al powder (99% Al, 80 µm average particle size, 1.6
g), and Al2 0 3 powder (alpha-alumina, 0.2 µm average
50 grain size), but softly agglomerated, i.e. can be crushed in an
agate mortar and pestle. A thorough study using a-Al2 0 3
powder was carried out, in which the effect of the concen-
tration of catalyst (alumina additive) and water temperature
was repeatedly made to ensure that the results are reproduc-
55 ible. The powder mixture was ground for 20 minutes in the
high-intensity Spex mill, and pelletized under 5000-6000
psi pressure. The -1 g pellets were immersed in tap water at
50° C. and Hydrogen release was recorded as a function of
60
time up to 70 minutes. The pH in the reactor increased
during this period from 6.5 to 7.8. These results are shown
in Table 7 and FIG. 6. All data are normalized to volume of
H2 generated per one gram of metal (Al). These data confirm
the previous results for the amount of catalyst up to 70 wt%.
65 However, unusually large amounts of Hydrogen (per 1 g Al)
are observed for very high amount of catalyst, i.e. 90 and
95%.
US 6,582,676 B2
17
TABLE 7
Effect of the Amount of Al201 Additive in Al/Al201System
Amount of
Al20 3 H 2 release: H 2 release: Time at
Catalyst after 1 hr max. rate max H 2 rel.
(wt%) (cc/1 g Al) (cc/min) (min)
5 24 0.8 26
5
18
Example 9
Results for Al/(Carbon+a-Al20 3)
This series of experiments were carried out with the view
to explore if the rate of Hydrogen generation could be
affected (i.e. also corrosion rate of Al accelerated) by using
a mixed catalyst. Another important ramification of this
10 26
20 208
30 333
50 487
70 782
90 1100
2.0
12
25
25
30
48
10
9.0
8.0
16
6.0
3.0
10 study is that the electrical conductivity in Al/Al20 3 pellets
could be increased by addition of carbon in the system. Such
conductive catalyst system is useful in combining
Al-assisted water split reaction with water electrolysis. The
95 1200 12 3.0
These results can be compared with that ofy-Al20 3 (derived
form boehmite calcined at 700° C. This shows that a-Al20 3
is as good a catalyst as y-Al20 3 in generating H2 from water.
This comparison is shown in FIG. 6.
15 results are presented in Table 9 and Table 10, and in the
respective FIG. 9 and FIG. 10. These tables show that
increasing either carbon or alpha-alumina in the system (as
catalysts) definitely improves Hydrogen generation.
However, when compared to each other, the effect of
Example 8
20 increasing carbon content is very similar to the effect of
increasing alpha-alumina content.
Hydrogen Generation using Aluminum and Carbon
In order to determine the role of carbon for the generation
of H2 a series of experiments were carried out with mixtures 25
of lampblack and Aluminum metal powder. The concentra-
tion of lampblack varied from 1 to 90 wt % of the total. The
powder was mixed in the Spex-mill for 20 min and pressed
into pellets at 1000-1200 lb load (corresponding to
5000-6000 psi). The tests were carried out in tap water 30
(pH=6.5 to 7.5) at 50° C. The results are shown in Table 8
and also plotted in FIG. 7. All data are normalized as
generation of Hydrogen per one gram of Aluminum metal.
The data show a pattern that is very similar to the Al/Al20 3
system (up to -60 wt % catalyst), the most effective system 35
found so far. However, for the C-catalyst above -60 wt %,
a decreasing amount of Hydrogen was released in this
system, in clear contrast to the Al/Al20 3 system.
TABLE 8
Effect of the Amount of Carbon Additive in Al/C System
Amount of H 2 release: H 2 release: Time at
C - Catalyst after 1 hr max. rate max H 2 rel.
(wt%) (cc/1 g Al) (cc/min) (min)
1 11 0.5 12
5 46 2.5 12
10 140 8.0 7
20 300 25 10
30 395 20 10
40 477 30 8
50 570 20 12
60 738 15 23
70 516 5.0 23
80 137 1.0 34
90 40 1.0 35
Table 6 shows that lampblack carbon is at least as
effective additive as alumina in Al/Al20 3 system in gener-
ating Hydrogen from water up to the concentration of 60 wt
40
45
50
55
% carbon. The results are compared in FIG. 8. It is possible 60
that in this system Al particles are partially (or totally, for
higher concentrations of carbon) coated by carbon. Because
carbon is not wetted by water, water could not come into
contact with the metallic phase and no Hydrogen could be
generated, for the higher concentrations of carbon. However, 65
for the concentrations up to 60 wt % there is significant
amount of H2 generation.
TABLE 9
Effect of Carbon (Lampblack) and Al2 0 3 (corundum) Additive in
Al/(C + a-Al2 0 3) System on Liz Generation, (increasing Concentration
of Corundum
Amount of Time at
Amount of Al2 0 3 - H 2 release: H 2 release: max H 2
C - Catalyst Catalyst after 1 hr max. rate release
(wt%) (wt%) (cc/1 g Al) (cc/min) (min)
20 10 357 0.5 10
20 20 516 2.5 12
20 30 550 8.0 12
20 40 712 25 16
20 50 803 20 16
TABLE 10
Effect of Carbon (Lampblack) and Al2 0 3 (corundum) Additive in
Al/(C + a-Al2 0 3) System on H 2 Generation,
(increasing Concentration of Carbon)
Amount of
Amount of Al20 3 - H 2 release: H 2 release: Time at
C - Catalyst Catalyst after 1 hr max. rate max H 2 rel.
(wt%) (wt%) (cc/1 g Al) (cc/min) (min)
10 30 438 16 20
20 30 550 18 12
30 30 700 15 14
40 30 750 9.0 12
Example 10
Effects of Various Other Ceramic Catalysts
(Additives) on H2 Release in Al/Catalyst Systems
This series of experiments was conducted to test the
catalytic abilities of 30 wt % of variety of other ceramic
powders blended with Al on releasing Hydrogen. All mix-
tures were prepared and tested as before. The results are
shown in Table 11. All data are normalized as generation of
Hydrogen per one gram of Aluminum metal. Both gamma-
Al203 and alpha-Al20 3 results are also included in this table
for comparison.
US 6,582,676 B2
19
TABLE 11
Effect of 30 wt % of Various Ceramic Additives Mixed with Al
H2 H2 Time at
Type of release: release: max H 2
Catalyst after 1 hr max. rate release.
(30 wt%) (cc/1 g Al) (cc/min) (min)
Si02 40 1.5 16
5
20
Example 12
Mg-MgO System
It is well known that fine Mg powder can ignite sponta-
neously when exposed to air. The reaction with oxygen is
sufficiently spontaneous to create an effect of violent
"burning", commonly utilized in firecrackers. Al may
CaC03 104
Ca(OH)2 106
China Clay 160
Ball Clay 215
Al20 3 0.2µm 201
5.0
25
10
7.5
10
1
5
20
18
10 behave similarly under certain conditions, i.e. very fine
un-oxidized, non-passivated powder exposed to air. For the
same reason, Mg metal should react with water, getting itself
oxidized and releasing Hydrogen in the process. Although
It must be noted that catalysts other than Al2 0 3 and
carbon are not very attractive in generating H2 from the
point of view of recyclability of the by-products of the
reaction, which would be Al(OHh, Al (unreacted) and the
catalyst (either reacted or unreacted). It would not be easy to
separate Al+Al(OH)x from other catalysts either mechani-
cally or chemically to recover [Al+Al(OH)x] for recycling.
15 Mg is currently more than double the price of Al, it is
thought prudent to explore water split reaction capability in
the system Mg-MgO. As before, Mg metal powder reagent
grade (-0.1 mm particle size) was mixed with very fine
MgO powder (reagent grade) using Spex mill for 20 min and
20 pelletized under 1000--1200 lb. The MgO content in the
mixture varied form 0% to 90 wt %. The water test was
carried out of 50° C. The pH was found to increase from 6.5
to -9.8 as the reaction progressed. These results are shown
in Table 13 and are plotted in FIG. 11.
It is interesting to note that ball clay and china clay, if
blended with Al, can also produce H2 , about 2/3 of the amount
generated with Al/Al2 0 3 composite powder. Again, it is
25
worth noting that these catalysts cannot be used commer-
cially as the final products cannot be recycled.
Example 11 30
Aluminum-Soluble Organic Salts
It appeared from the above, that just maintaining clean
surface (i.e. non-oxidized surface) of Aluminum metal could 35
split water into H2 and Al(OH)x· This can be accomplished
by use of water-soluble organic compounds, such as poly-
vinyl alcohol (PVA) or polyethylene glycol (PEG) with Al
metal, for spliting water and generating Hydrogen. To test
this concept, Al metal was mixed with PEG ( 4000 molecular 40
weight, 3-20 wt%), Spex milled for 20 minutes, pelletized
(as described before) and water tested at a neutral pH and
50° C. The results are shown in Table 9. The results indicate
that it is indeed possible to generate H2 using Al+water
soluble organic polymers. However, the results are different 45
than those obtained for carbon or Aluminum oxide additives.
The amount of Hydrogen generated (-225 cc per one gram
of Al) appears to be independent on PEG concentration. The
extent of H2 generation corresponds to -18% of Al con-
verted to Al(OH)x· This value is similar to the system with 50
ball clay Table 8. This may be a reflection of a true
conversion efficiency of Al metal powder under these
experimental conditions.
TABLE 12
Effect of the Amount of Polyethylene Glycol Additive
in Al on H Generation
Amount of H2 H2 Time at
PEG release: release: max H 2
Catalyst after 1 hr max. rate release
(wt%) (cc/1 g Al) (cc/min) (min)
3 220 3.0 20 (steady)
5 215 4.0 20 (steady)
55
60
Amount of
MgO
Catalyst
(wt%)
0*
10*
20*
30*
50*
70
80
90
TABLE 13
Effect of the Amount of MgO
Additive in Mg/MgO System
H2 H2
release: release:
after 1 hr max. rate
(cc/1 g Mg) (cc/min)
45 3.0
55 39
62 23
59 19
55 11
110 1.3
110 1.0
108 0.3
*these experiments were done with a coarser Mg powder
Time at
max H 2
rel.
(min)
10
20
4
15
* these experiments were done with a coarser Mg powder
There is a relatively small and approximately constant
(50-60 cc) volume of H2 released for these systems up to 50
wt % catalyst. For higher amounts of the catalyst the
Hydrogen release was approximately 110 cc/1 g of Mg.
Mg/MgO system does not appear to have the ability of
Al/Al2 0 3 system in splitting water in neutral pH. During the
water test there was a continuous rise of pH of the water,
from -6.5 to -9.0.
Example 13
The system of Al+Mg metals and Aluminum oxide was
studied to evaluate the effect of mechanically alloying two
metals on Hydrogen generation from water. The powder
mixtures were produced following the same procedure
described before. The composition of the mixture varied in
10 230 3.7
20 250 4.0
20 (steady)
25 65 such a way that the concentration of Al metal was kept
constant to 50 wt %, and part of Al2 0 3 was replaced with
Mg, as shown in Table 14.
US 6,582,676 B2
21
TABLE 14
Effect of the Amount of Al20 3 Additive in (Mg,Al)/Al20 3 System
H2 H2
release: release: H2
Amount Amount Amount after 1 hr after 1 hr release: Time at
of Al20 3 of Al of Mg (cc/1 g (cc/1 g max. max H 2
Catalyst Metal Metal total Al rate rel.
(wt%) (wt%) (wt%) Metal) Metal) (cc/min) (min)
45 50 5 416 458 35 2
40 50 10 318 458 45
30 50 20 314 440 40
25 50 25 266 400 35
5
10
22
Having described the invention modifications will be
evident to those skilled in the art without departing from the
spirit of the invention as defined in the appended claims.
What is claimed is:
1. A method of producing Hydrogen comprising reacting
metal particles selected from the group consisting of Alu-
minum (Al), Magnesium (Mg), Silicon (Si) and Zinc (Zn)
with water in the presence of an effective amount of a
catalyst at a pH of between 4 and 10 to produce reaction
products which include Hydrogen, said catalyst is selected
to be suitable for said metal particles being reacted and from
the group consisting of alumina, suitable ceramic com-
pounds containing aluminum ions, Carbon (C), calcium
carbonate (CaC03), calcium hydroxide (Ca(OH)2), polyeth-
ylene glycol (PEG), and combinations thereof, magnesium
15 oxide (MgO), Silicon dioxide (Si02), and Zinc oxide (ZnO)
that facilitate said reacting said metal with said water and
improves production of said Hydrogen.
The results showed clearly that when Al2 0 3 concentration
was reduced the Hydrogen generation was decreased per
gram of total metal (Al+Mg). If the Hydrogen generation
was recalculated on the basis of Al present, then the results
show that the amount of H2 (per 1 g of Al) remained about 20
constant, although the catalyst concentration was reduced.
This indicates that Mg helped somewhat in generating
Hydrogen. However, overall mechanical alloying of Al with
Mg did not significantly improve Hydrogen generation. On
top of that, this is not a very attractive system for
commercialization, as the by-products of reaction, i.e.
Al(OH)3 and Mg(OH)2 , as well as unreacted Al and Mg, can
not be easily separated for recycling.
2. A method as defined in claim 1 wherein said metal and
catalyst are blended into intimate physical contact.
3. A method as defined in claim 2 wherein said catalyst is
in the form of catalyst particles, said metal particles and said
catalyst particles are particles in the size range between 0.01
µm and 1000 µm.
4. A method as defined in claim 3 wherein said metal is
25 Aluminum (Al) and said catalyst is selected from the group
consisting of Alumina, suitable ceramic compounds con-
taining aluminum ions, Carbon (C), calcium carbonate
(CaC03), and calcium hydroxide (Ca(OH)2 ).
Example 14
Addition of Other Metal-Oxide Systems
In order to explore further if mechanical nixing of other
metals and their corresponding oxides can also help in
water-split reaction generating Hydrogen, attempts were
made to test the following systems: Fe-Fe3 0 4 , Ni-NiO,
Cu-Cu20, Si-Si02 , Zn-ZnO and Ti-Ti02 . The con-
centration of the oxide phase was maintained constant at 30
wt % in every system The procedure for pellet preparation
and testing was also the same as before (20 min of Spex
milling followed by 5000-6000 psi pelletization; water test
at pH=6.8 to 7.2, at 50° C.). The results are shown in Table
15.
TABLE 15
Additional Metal-Oxide Systems: Effect of 30 wt % of
Various Ceramic Oxides Mixed with the Parent Metal
System
(30 wt% oxide)
Fe-Fe30 4
Cu---Cu2 0
Ni-NiO
Si-Si02
Zn-ZnO
Ti-Ti02
H 2 release:
after 1 hr
( cc/1 g metal)
0
0
2
195
34
0
Theoretical
H 2 release
( cc/1 g metal)
12%
10%
5. A method as defined in claim 4 wherein said catalyst is
30 Alumina and/or a ceramic compound containing aluminum
10ns.
6. A method as defined in claim 5 wherein said catalyst is
a ceramic compound containing aluminum ions selected
from the group consisting of Aluminum oxides, Aluminum
35 hydroxides and combination thereof.
7. A method as defined in claim 4 wherein said catalyst is
carbon.
8. A method as defined in claim 2 wherein said metal is
Aluminum (Al) and said catalyst is selected from the group
40 consisting of alumina, suitable ceramic compounds contain-
ing aluminum ions, Carbon (C), calcium carbonate
(CaC03), and calcium hydroxide (Ca(OH)2 ).
9. A method as defined in claim 8 wherein said catalyst is
selected from the group consisting of Alumina and suitable
45 ceramic compounds containing aluminum ions.
10. A method as defined in claim 9 wherein said catalyst
is Alumina and/or a ceramic containing compound alumi-
num 10ns.
11. A method as defined in claim 10 wherein said catalyst
50 is a ceramic containing aluminum ions compound selected
from the group consisting of Aluminum oxides, Aluminum
hydroxides and combinations thereof.
12. A method as defined in claim 8 wherein said catalyst
is Alumina and/or a ceramic containing aluminum ions
55 compound.
The theoretical (maximum) release of H2 in water split
reaction for the various metals is obtained on the basis of the 60
13. A method as defined in claim 12 wherein said catalyst
is a ceramic containing aluminum ions compound selected
from the group consisting of Aluminum oxides, Aluminum
hydroxides and combinations thereof.
14. A method as defined in claim 2 wherein said metal is
Aluminum (Al) and said catalyst comprises poylethylene
glycol (PEG).
following reactions:
It is interesting to note that both Si and Zn can split water
at 50° C. in neutral pH, although not very efficiently.
15. A method as defined in claim 2 wherein said metal is
Magnesium (Mg) and said catalyst is magnesium oxide
65 (MgO).
16. A method as-defined in claim 2 wherein said metal is
Silicon (Si) and said catalyst is Silicon dioxide (Si02).
US 6,582,676 B2
23
17. A method as defined in claim 2 wherein said metal is
Zinc (Zn) and said catalyst is Zinc oxide (ZnO).
18. A method as defined in claim 2 wherein said blended
into intimate physical contact comprises mixing said metal
and said catalyst in a mixer that pulverizes said metal and s
said catalyst and exposes fresh surfaces of said metal.
19. A method as defined in claim 18 wherein said metal
and said catalyst are formed into pellets and said pellets are
then mixed with said water.
20. A method as defined in claim 18 wherein said metal 10
is Aluminum (Al) and said catalyst is selected from the
group consisting of Alumina, suitable ceramic compounds
containing aluminum ions, Carbon (C), calcium carbonate
(CaC03 ), and calcium hydroxide (Ca(OH)2 ).
21. A method as defined in claim 20 wherein said catalyst 15
is Alumina and/or a ceramic compound containing alumi-
num 10ns.
24
22. A method as defined in claim 21 wherein said catalyst
is a ceramic containing aluminum ions compound selected
from the group consisting of Aluminum oxides, Aluminum
hydroxides and combinations thereof.
23. A method as defined in claim 2 wherein said metal is
Aluminum (Al) and said catalyst comprises a combination
of at least one additive selected from the group consisting of
Alumina and suitable ceramic compounds containing alu-
minum ions compounds and at least one additive selected
from the group consisting of organic water soluble com-
pounds.
24. A method as defined in claim 17 wherein said water
soluble organic compound is poylethylene glycol (PEG).
* * * * *

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CIP
298 Cat scratch disease
swinuning, jumping, and running. Felis pardus is the
only species of true leopard; however, Uncia uncia,
the snow leopard or o~nce, also is called a leopard.
This latter species occurs in the Himalayas of central
Asia at high altitudes. The leopard has a more exten-
sive distribution than any other species of Felidae.
These animals hunt ceaselessly and have been known
to eat humans. They can be tamed in captivity when
young, but few are tamed since they cannot be
trusted.
Lian. Pelis leo was a common animal in the Near
East, and its range extended into Europe during pre-
historic times. In historical times it was recorded as
continuing to inhabit the Balkan Peninsula. It has
come to be restricted in its distribution as a result of
the advances of humans. It is still abundant in the
savanna areas between Senegal and East Africa,
where there is much herbivorous fauna to prey upon.
It is not found in deserts or thickly forested regions.
The lion may weigh as much as 550 lb (248 kg) and
reach a height of 3 ft (0.9 m) and a length of 6V2 ft
(1.9 m). It is the largest African carnivore. There is
one litter of 2~4 young per year after a gestation pe-
riod of about 15 weeks. The life-span may be as long
as 40 years. The lion hunts at night and is silent while
approaching its prey in order to surprise it. Various
races of this species have been described, such as
Cape, Masai, Somali, and Indian lions, but they show
few differences in color and size.
Tiger. The tiger is represented by a single species,
F. tigris. It inhabits the forests of Asia) Sumatra,
Java, and southern Siberia. As a consequence of the
wide climatic and geographical distribution of tigers,
they show a wide range of coloration and size, and a
number of varieties are recognized. After a gestation
period of 3 months, two or three cubs are born help-
less and blind. There is one litter every second year,
and usually only one cub of each litter survives. Ti-
gers breed in captivity, and crosses between the lion
and tigress (the liger) and between the tiger and lion-
ess (the tigron) have been obtained. The tiger takes
any food available and, like many members of the cat
family, returns to the kill until it is consumed. SEE
CARNIVORA.
Charles B. Curtin
Cat scratch disease
A benign infectious illness, transmitted principally by
cats and characterized by mild systemic symptoms,
localized lymphadenopathy, and spontaneous resolu-
tion. The causative agent is unknown, but numerous
gram-negative bacilli· have been demonstrated in the
lymph nodes of affected individuals. The disease oc-
curs worldwide, primarily affecting adults under the
age of 30. In temperate climates, the illness exhibits
a seasonal pattern, most cases occurring between Sep-
tember and February, with a peak incidence in De-
cember. The majority of the individuals have a his-
tory of exposure to cats, and a history of scratch or
bite can be elicited in three-quarters of them. Despite
transmitting this illness to humans, affected cats
themselves remain healthy.
Ten to fourteen days following a scratch or bite,
infected individuals first notice the cardinal feature of
the disease: tender regional lymphadenopathy. Half of
the individuals develop a nonpruritic erythematous
papule at the site of inoculation. The arms are most
commonly involved, followed by the head and n
and the legs. Approximately two-thirds of the int
persons will develop systemic symptoms, Priman
malaise and fever. Atypical manifestations occur
approximately 10% of those infected: these incl
swelling of the lymph nodes in front of the e
association with conjunctivitis and fever, and
commonly encephalitis. Laboratory tests are usuau.
normal. There is no specific therapy available for thy
treatment of this illness, but most individuals recovee
completely within 2 months. Abscess formatio!
within lymph nodes occurs in as many as one-third of
the cases, and occasionally it is necessary to drain pus
from these infected nodes. •.
The diagnosis can be made with reasonable assur-
ance if three of the four following criteria are met: a·
history of cat (or other animal such as a dog) scratch.
or bite; characteristic histopathologic changes in in>
volved lymph nodes; a positive Hanger-Rose test (a
skin test, using antigen prepared from pus obtained
from patients with cat scratch disease); and a negative
evaluation for other illnesses. Three different histo-;
logic patterns have been described; hyperplastic,
granulomatous, and suppurative. All phases may be.
present within the same lymph node, a feature that is
useful in suggesting the diagnosis. The skin test is•
positive in 90% of the individuals with the disease;
unfortunately, skin test material is not readily avail-
able. A wide variety of clinical disorders that share a
propensity to cause lymphadenopathy may be con-
fused with this disease. It is particular I y important to
realize that this illness may mimic neoplastic condi- ••
tions.
Peter Densen
Bibliography. A. Carithers, Cat scratch disease,
Amer. J. Dis. Child., 119:200-203, 1970; W. M.
Heroman and W. S. McCurley, Cat scratch disease,
Otol. Clin. N. Amer., 15:649-658, 1982; D. J. Wear
et al. , Cat scratch disease: A bacterial infection, Sci-
ence, 221:1403-1405, 1983.
Catalysis
The phenomenon in which a relatively small amount.··
of foreign material, called a catalyst, augments the
rate of a chemical reaction (positive catalysis), or de-
creases it (negative catalysis) without itself being con~•••
sumed. A catalyst is material, and not light or heat.•••
It changes a rate. SEE ANTIOXIDANT; lNHTBlTOR (cHEMIS·
TRY).
If the reaction A + B-+ D occurs very slowly but
is catalyzed by some catalyst, Cat, the addition of Cat··
must open new channels for the reaction. In a very
simple case {1), the two propagation processes, which.
A + Cat ~ ACat } . .
ACat + B ~ D + Cat Chain propagation
A + B ~ D Overall reaction
are fast compared to the uncatalyzed reactions, A + ·•
B -+ D, provide the new channel for reaction. The
catalyst reacts in the first step; but is regenerated in.
the second step to commence a new cycle, A catalytic:
reaction is thus a kind of chain reaction. SEE CHAIN
REACTION (CHEMISTRY) .
If a reaction is in chemical equilibrium under some .·
fixed conditions, the addition of a catalyst cannol
change the position of equilibriuom without violating .·.
o ••
\· ..
second law of thermodynamics. Therefore, if a
yst augments the rate of A + B --+ D, it must
augment the reverse rate, D--+ A + B.
categories. Catalysis is conventionally divided
tO three categories: homogeneous, heterogeneous,
(I enzyme. Heterogeneous catalysis plays a domi-
.· t role in chemical processes in the petroleum, pet-
hemical, and yhemical industries. Homogeneous
alysis is important in the petrochemical and chem-
industries. Enzyme catalysis plays a key role in
metabolic processes and in some industries, such
· the fermentation industry.
Homogeneous. In homogeneous catalysis, reactants,
oducts, and catalyst are all present molecularly in
e phase, usually liquid. Examples are the hydroge-
ation of 1-hexene in a hydrocarbon solvent catalyzed
y dissolved [(CJfs)3 PhRhH [reaction (2)] and the
'M2=CHCH2CH2CH2CH3 + H2-+
CHsCH/;H2CH 2CH2CH3 (2)
ydrolysis of an ester catalyzed by acid [reaCtion (3)].
.·: H+
· ... · CH3COOC2H5 + H20-+ CH3COOH + HOC2H5 (3)
.££HOMOGENEOUS CATALYSTS.
·.·.Heterogeneous. In heterogeneous catalysis, the cat-
·. yst is in a separate phase. Usually the reactants and
rbducts are in gaseous or liquid phases and the cat-
. · st is a solid. The catalytic reaction occurs on the
ace of the solid. Examples are the dehydration
· d the dehydrogenation of isopropyl alcohol [reac-
'ons (4) and (5)]. Reaction (4) can be affected by
+·c· ..
··:H3CHOHCH 3 -+
CH 3CH=CH 2 + H20 Dehydration (4)
.bH3CHOHCHs-+
CH3COCH 3 + H2 Dehydrogenation (5)
assing the vapors of the alcohol over alumina at
bout 570°F (300°C), and reaction (5) over copper at
90°F (200°C). SEE HETEJWGENEOUS CATALYSIS.
>Enzyme. Transformations of matter in living organ-
isms occur by an elaborate sequence of reactions,
:most of which are catalyzed by biocatalysts called en-
zymes. Enzymes are proteins and therefore of colloi-
'dal dimensions. Although studies of mterrelations be-
jween homogeneous catalysis and heterogeneous
catalysis have been developing, enzyme catalysis re-
!llains a .rather separate area in the nature of the cata-
Jyst and in the type of reactions catalyzed. SEE ENZYME.
Selectivity. In most cases, a given set of reactants
;~ou!d react in two or more ways, as exemplified by
:.reactions (4) and (5). The degree to which just one of
,the possible reactions is favored over the other is
~alled selectivity. Selectivity is a key property of a
catalyst in any practical application of the catalyst.
· Robert L. Burwell, Jr.
,~atalytic converter
'An aftertreatment device used for pollutant removal
from automotive exhaust. Since the 1975 model year,
creasingly stringent government regulations for the
.Jlowable emission levels of carbon monoxide (CO),
Catalytic converter 299
hydrocarbons (HC), and oxides of nitrogen (NOx)
have resulted in the use of catalytic converters on
most passenger vehicles sold in the United States.
The task of the catalytic converter is to promote
chemical reactions for the conversion of these pollu-
tants to carbon dioxide, water, and nitrogen. . .
By definition a catalyst is an agent which promotes
the rates at which chemical reactions occur, without
affecting the final equilibrium as dictated by thermo-
dynamics, but which itseif remains unchanged. For
automotive exhaust applications, the pollutant re-
moval reactions are the oxidation of carbon monoxide
and hydrocarbons and the reduction of nitrogen ox-
ides. Metals, base and noble, are the catalytic agents
most often employed for this task. Small quantities of
these metals, when present in a highly dispersed form
(often as mdividual atoms), provide sites upon which
the reactant molecules may interact and the reaction
proceed. SEE AIR.-POLLUTlON CONTROL.
In addition to the active. metal, the converter con-
tains a support component whose functions mclude
yielding structural integrity to the device, proyiding a
large surface area for metal dispersion, and promoting
intimate contact between the exhaust gas and the cat-
alyst. Two types of supports are used: pellets and mo-
noliths. The pelleted converter consists of a packed
bed of small, porous, ceramic spheres whose outer
shell is impregnated with the active metal .. The_ mo-
nolith is a honeycomb structure consisting of a large
number of cllannels parallel to the direction of ex-
haust gas flow. The active metals reside in a thin
layer of high-surface-area ceramic (usually ')'-alu-
mina) placed on the walls of the honeycomb. fu either
system the support is contained in a stainless steel can
installed in the exhaust system ahead of the muffler.
Two types of catalyst systems, oxidation and three-
way, are found in automotive applications. Oxidation
catalysts remove only CO and HC, leaving NOx un-
changed. An air pump is often used to add air to the
engine .exhaust upstream of the catalyst, thus ensuring
an oxidizing atmosphere. Platinum and palladium are
generally used as the active metals in oxidation .cata-
lysts.Three-way catalysts are capable of removing all
three poilutants simultaneously, provided that the cat-
alyst is maintained in a "chemically correct" envi-
ronment that is neither overly oxidizing or reducing.
To achieve this requires that the engine air-fuel ratio
always be at,. or very near, stoichiometry under all
vehicle operating conditions. Feedback air-fuel ratio
control systems are often used to satisfy this require-
ment. Platinum, palladium, and rhodium are the met-
als most often used in three-way catalysts. lri addi-
tion, base metals are frequently added to improve the
ability of the catalyst to withstand small, transient
perturbations in air-fuel ratio. In both oxidation and
three-way catalyst systems, the production of undesir-
able reaction products, such as sulfates and ammonia,
must be avoided.
Maintaining effective catalytic functi~n over long
periods of vehicle operation is often a major problem.
Catalytic activity will deteriorate due to two causes,
poisoning of the active sites by contaminants, such as
lead and phosphorus, and exposure to excessively
high temperatures. Catalyst overtemperature is often
associated with engine malfunctions such as exces-
sively rich operation or a large amount of cylinder
misfire. To achieve efficient emission control, it is
thus paramount that catalyst-equipped vehicles be op-
erated only with lead-free fuel and that proper engine