Mixed-reactant fuel cells with selective electrodes
A mixed reactant fuel cell (MRFC) including a MRFC-optimized electrocatalyst utilizing a combination of selective catalysts and selective fuel distributors.
1. A method for producing a cathode for a mixed reactant fuel cell comprising:
making a self-supporting porous cathode catalyst by:
mixing metal, nitrogen, and carbon precursors with a plurality of dispersed sacrificial support particles under sufficient conditions to allow the metal, nitrogen and carbon precursors to coat the sacrificial support particles and form a metal-nitrogen-carbon (M-N—C) compound/sacrificial support matrix;
heat treating the M-N—C compound/sacrificial support matrix to produce active sites in the matrix; and
removing the sacrificial support, thereby producing a self-supporting porous catalyst;
mixing the self-supporting porous catalyst with carbon black and an ionomer to form an ink;
coating a flexible gas diffusion layer with the ink.
2. The method of claim 1 wherein the carbon black makes up no more than 60% of the ink.
3. The method of claim 1 wherein the ink contains 30% wt ionomer.
4. The method of claim 1 wherein the porous catalyst is loaded at between 0.1and 0.6 mg cm-2.
5. The method of claim 1 wherein the porous catalyst is Fe-AAPyr.
6. The method of claim 1 wherein the gas diffusion layer comprises woven carbon fibers.
7. The method of claim 1 wherein the self-supporting porous catalyst comprises a bimodal pore distribution with a first distribution of pores in the 40-60 nm range and a second distribution of pores with an average diameter of approximately 200 nm range.
8. A method for producing a cathode for a mixed reactant fuel cell comprising:
making a self-supporting porous cathode catalyst by:
mixing Fe-AApyr precursors with a sacrificial support under sufficient conditions to allow the Fe-AApyr precursors to coat the sacrificial support and form a matrix;
heat treating the matrix to produce active sites in the matrix; and
removing the sacrificial support, thereby producing a self-supporting porous catalyst;
mixing the self-supporting porous catalyst with carbon black and an ionomer to form an ink;
coating a flexible gas diffusion layer with the ink.
9. The method of claim 8 wherein the carbon black makes up no more than 60% of the ink.
10. The method of claim 8 wherein the ink contains 30% wt ionomer.
11. The method of claim 8 wherein the porous catalyst is loaded at between 0.1 and 0.6 mg cm-2.
12. The method of claim 8 wherein the Fe-AAPyr precursors are aminoantipyrine and iron nitrate.
13. The method of claim 8 wherein the gas diffusion layer comprises woven carbon fibers.
14. The method of claim 8 wherein the self-supporting porous catalyst comprises a bimodal pore distribution with a first distribution of pores in the 40-60nm range and a second distribution of pores with an average diameter of approximately 200nm range.