NON-PRECIOUS FUEL CELL CATALYSTS COMPRISING POLYANILINE
A method of producing a catalyst suitable for use in a membrane electrode assembly involves providing a mixture comprising a polyaniline precursor and a catalyst support; adding to said mixture an oxidant and a compound comprising a transition metal; agitating said mixture sufficiently to result in polyaniline polymerization; drying the mixture; heating the dried mixture in an inert atmosphere at a temperature of from about 400° C. to about 1000° C.; leaching the mixture with an acid solution; heating the resulting mixture in an inert atmosphere at a temperature of from about 400° C. to about 1000° C. The second heating improves the performance of the catalyst.
1 . A method of producing a catalyst suitable for use in a membrane electrode assembly, comprising:
a) providing a mixture comprising a polyaniline precursor and a catalyst support;
b) adding to said mixture an oxidant and a compound comprising a transition metal;
c) agitating said mixture sufficiently to result in polyaniline polymerization;
d) drying the mixture;
e) heating the dried mixture in an inert atmosphere at a temperature of from about 400° C. to about 1000° C.; and thereafter
f) leaching the mixture with an acid solution; and thereafter
g) heating the mixture in an inert atmosphere at a temperature of from about 400° C. to about 1000° C.
2 . The method of claim 1 , wherein the catalyst support comprises carbon black, multi-walled carbon nanotubes, non-carbon supports, and combinations thereof.
3 . The method of claim 2 , wherein the catalyst support further comprises TiO 2 , Al 2 O 3 , or combinations thereof.
4 . The method of claim 1 , wherein the mixture comprising the polyaniline precursor and the catalyst support is an acidic mixture.
5 . The method of claim 1 , wherein the oxidant is ammonium peroxydisulfate.
6 . The method of claim 1 , wherein the transition metal is cobalt, iron, or combinations thereof.
7 . The method of claim 1 , wherein the heating temperature for each heating is from about 800° C. to about 900° C.
8 . The method of claim 1 , further comprising adding to the mixture a solution comprising a perfluorinated sulfonic acid ionomer to produce a catalyst ink.
9 . The method of claim 8 , further comprising applying the catalyst ink to a component of a membrane electrode assembly.
10 . A composition produced by a process comprising:
forming a cold aqueous suspension of carbon and aniline,
forming a first product by combining the suspension with an oxidant and a transition metal-containing compound and allowing the resulting mixture to react under conditions suitable for polymerization of the aniline to polyaniline, the transition metal containing compound including a metal selected from iron and cobalt,
drying the first product,
heating the dry first product at a temperature of from about 400° C. to about 1000° C. to form a second product,
leaching the second product with acid, and thereafter
repeating the step of heating at a temperature of from about 600° C. to about 1000° C. to form a third product.
11 . The composition of claim 10 , wherein the heating temperature for each heating is from is from about 800° C. to about 900° C.
12 . The composition of claim 10 , wherein the process further comprises combining the third product with a solution including a perfluorinated sulfonic acid ionomer.
13 . The composition of claim 12 , wherein the heating temperature for each heating is about 900° C.
14 . A membrane electrode assembly comprising a catalyst prepared by a process comprising:
a) providing a mixture comprising a polyaniline precursor and a catalyst support;
b) adding to said mixture an oxidant and a compound comprising a transition metal;
c) agitating said mixture sufficiently to result in polyaniline polymerization;
d) drying the mixture;
e) heating the dried mixture in an inert atmosphere at a temperature of from about 400° C. to about 1000° C.; and thereafter
f) leaching the mixture with an acid solution; and thereafter
g) heating the mixture in an inert atmosphere at a temperature of from about 400° C. to about 1000° C. to form a product, and thereafter
combining the mixture with a solution including a perfluorinated sulfonic acid ionomer.
15 . The membrane electrode assembly of claim 14 , wherein the catalyst support comprises carbon black, multi-walled carbon nanotubes, non-carbon supports, and combinations thereof.
16 . The membrane electrode assembly of claim 14 , wherein the catalyst support further comprises TiO 2 , Al 2 O 3 , or a combination thereof.
17 . The membrane electrode assembly of claim 14 , wherein the mixture comprising the polyaniline precursor and the catalyst support is an acidic mixture.
18 . The membrane electrode assembly of claim 14 , wherein the oxidant is ammonium peroxydisulfate.
19 . The membrane electrode assembly of claim 14 , wherein the transition metal is cobalt, iron, or a combination thereof.
20 . The membrane electrode assembly of claim 14 , wherein the temperature for each heating is from about 800° C. to about 900° C.