Electrodes are prepared by vacuum deposition of platinum on nickel substrate with conventional vapor-deposition apparatus. Amount of platinum loaded on substrate can be veried by changing exposure time during deposition. These electrodes are significantly more effective than conventional oxygen electrodes

Asher, W. J.

Batzold, J. S.

English

NASA Technical Reports Server

April 1974	 B73-10475 
•	 NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Vapor-Deposited Platinum as a Fuel-Cell Catalyst 
S
In this and several other NASA Tech Briefs (see 
Note 1), a new fuel-cell system is described. Through 
the development of an efficient catalyst and the 
design of several new fuel-cell components and con-
figurations, an important step has been taken toward 
the day when fuel cells may be used to replace internal 
combustion engines. This development is particularly 
important today, because fuel cells are essentially 
emission-free and, compared to internal combustion 
engines or generators, obtain considerably more power 
from the same quantity of fuel. 
The first step in the design of a fuel cell is the 
development of a catalyst that will efficiently push the 
energy-releasing electrochemical reaction in the cell. 
This may be done with a new platinum catalyst, with an
unusually high activity. It is prepared by vapor deposi-
tion on a porous nickel substrate. The nickel plates are 
prepared by hot sinter pressing of nickel powder, to 
form a plaque with an average pore size of 1 micrometer 
and a total porosity of 20 percent. 
The electrodes are prepared by vacuum deposition 
of the platinum on the nickel substrate with a con- 
ventional vapor-deposition apparatus. The amount of 
platinum loaded on the substrate can be varied by 
changing the exposure time during deposition. The first 
remarkable result of this process is that the performance 
of the catalyst is almost independent of the loading 
(see Figure 1). This is not the case for catalysts prepared 
by Other methods (see Figure 2). 
	
I	 I	 I	 I	 I	 I
02.6MKOH,60°C 
A Ap 16 psi 16 ps,
Pt. Loading. 
pgmlcm 2	 \\ b 
12 
0104 
	
V140	 I 
0930
	
I	 I	 I	 I	 I	 I 
0.9 
CN	 0.7 
> 
0 
>	 0.5 
0.3
S
10	 20	 50	 100 
Current Density (mA/cm2) 
Figure 1. Performance as a Function of Loading: 
Vapor-Deposited Pt. Electrodes
(continued overleaf) 
This documentwas prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information Contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000475 2020-03-17T07:31:52+00:00Z
0.9 
CIA	 0.7 I 
> 
0 
>	 0.5 
0.3
02. 6M KOH, 600
 c 
pgm,cm21 
Pt. Loadi 
V 250 
O 282 
01020 
5200 
+8620
. 
1	 2	 5	 10	 20	 50	 100 
Current Density (mA/cm2) 
Figure 2. Performance as a Function of Loading: 
Sputtered Pt. Electrodes 
Thus, less of the expensive platinum catalyst may be 
used, an important economical breakthrough. More 
important, however, is the discovery that these elec-
trodes, even with the low platinum loading, are signifi-
cantly more effective than conventional oxygen elec-
trodes. Under identical conditions, the conventional 
electrode has a specific activity of 5 mA/mg of catalyst; 
and the vapor-deposited electrode has an activity of 
83 mA/mg, a sixteenfold improvement. 
Notes: 
1. The development of a fuel-cell system is further 
described in the following NASA Tech Briefs: 
B73-10489, Fuel-Cell Heat and Mass Plate 
B73-10472, A Methanol/Air Fuel-Cell System 
B73-10473, An Electrochemical Engine
2. Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&PS-TU 
Marshall Space Flight Center, Alabama 35812 
Reference: B73-10475 
Patent status: 
NASA has decided not to apply for a patent. 
Source: W. J. Asher and

J. S. Batzold of
Exxon Corp.
under contract to
Marshall Space Flight Center
(MFS-2 13 17)
. 
B73-10475	 Category 04, 07


Vapor-deposited platinum as a fuel-cell catalyst

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