Non-precious metal catalysts prepared from precursors comprising cyanamide and polyaniline
View Patent ↗A catalyst for oxygen reduction reaction (ORR) for a fuel cell was prepared by pyrolyzing a mixture of polyaniline, cyanamide, carbon black, and a non-precious metal salt under an inert atmosphere. The pyrolyzed product was treated to remove acid soluble components and then pyrolyzed again. The resulting powder was used to prepare a cathode for a membrane electrode assembly that was used in a fuel cell. When iron(III) chloride was used as the salt, the resulting catalyst was porous with a web-shaped structure. It displayed a maximum power density of 0.79 W/cm at 0.4 V in H 2 /O 2 at 1.0 bar back pressure.
1. A catalyst prepared by a process comprising:
adding an oxidant to a mixture of aniline, cyanamide, and a non-precious metal salt in an aqueous acid, the non-precious metal salt being selected from an iron salt, a cobalt salt, a manganese salt, and combinations thereof;
adding carbon black to the mixture;
drying the mixture;
heating the mixture at a temperature of about 700° C. to about 1100° C. under an inert atmosphere;
removing acid soluble components from the mixture; and
heating the mixture again at a temperature of about 700° C. to about 1100° C. under an inert atmosphere.
2. The catalyst of claim 1 , wherein the non-precious metal salt comprises a halide, acetate, sulfate, or phosphate.
3. The catalyst of claim 1 , wherein the non-precious metal salt comprises an iron halide salt.
4. The catalyst of claim 1 , wherein the oxidant comprises ammonium persulfate.
5. The catalyst of claim 1 , wherein the carbon black comprises carbon black pretreated with nitric acid.
6. A catalyst composition prepared by a process comprising:
mixing the catalyst of claim 1 with water and with an ionomer suspension.
7. The catalyst composition of claim 6 , wherein the non-precious metal salt comprises a halide, acetate, sulfate, or phosphate.
8. The catalyst composition of claim 6 , wherein the non-precious metal salt comprises an iron halide salt.
9. The catalyst composition of claim 6 , wherein the ionomer suspension comprises an ionomer comprising a copolymer of a perfluorosulfonic acid and a polytetrafluoroethylene.
10. A membrane electrode assembly comprising:
a membrane; and
a gas diffusion layer;
wherein the catalyst composition of claim 6 is applied to a first side of the membrane and to a first side of the gas diffusion layer, and
the first side of the membrane is in direct contact with the first side of the gas diffusion layer.
11. The membrane electrode assembly of claim 10 , wherein the iron salt is an iron halide salt.
12. The membrane electrode assembly of claim 10 , wherein the iron salt is FeCl 3 .
13. The membrane electrode assembly of claim 10 , wherein the ionomer suspension comprises an ionomer comprising a copolymer of a perfluorosulfonic acid and a polytetrafluoroethylene.
14. A method of preparing a catalyst, comprising:
adding an oxidant to a mixture of aniline, cyanamide, and a non-precious metal salt in an aqueous acid,
the non-precious metal salt being selected from an iron salt, a cobalt salt, a manganese salt, and combinations thereof;
adding carbon black to the mixture;
drying the mixture;
heating the mixture at a temperature of about 700° C. to about 1100° C. under an inert atmosphere;
removing acid soluble components from the mixture; and
heating the mixture again at a temperature of about 700° C. to about 1100° C. under an inert atmosphere.
15. The method of claim 14 , wherein the non-precious metal salt comprises a halide, acetate, sulfate, or phosphate.
16. The method of claim 14 , wherein the non-precious metal salt comprises an iron halide salt.
17. The method of claim 14 , wherein the oxidant comprises ammonium persulfate.
18. The method of claim 14 , wherein the carbon black comprises carbon black pretreated with nitric acid.