Melamine modification of fuel cell electrodes
A method for forming a melamine-modified electrode that includes providing a metal based electrode and patterning a surface of the metal-based electrode by contacting the electrode with a melamine solution to form a patterned metal-based electrode. The patterned metal-based electrode includes metal sites blocked with melamine molecules and metal sites which are not blocked such that the metal-based electrode selectively adsorbs O 2 instead of at least one of sulfate, phosphate, or sulphonate. A range of 20% to 40% of the metal sites are blocked with melamine molecules.
1. A method comprising:
providing a metal-based electrode;
patterning a surface of the metal-based electrode by contacting the electrode with a melamine solution to form a patterned metal-based electrode, the patterned metal-based electrode comprising metal sites blocked with melamine molecules and metal sites which are not blocked such that the metal-based electrode selectively adsorbs O 2 instead of at least one of sulfate, phosphate, or sulphonate,
wherein a range of 20% to 40% of the metal sites are blocked with melamine molecules.
2. The method of claim 1 , wherein the metal-based electrode comprises Pt, Pd, Ir, or Rh, or a Pt alloy with one or more of Co, Ni, Fe, Ti, Cr, V, or Mn.
3. The method of claim 1 , wherein the metal-based electrode comprises Pt(100), Pt(111), Pt(1099), or polycrystalline Pt.
4. The method of claim 1 , wherein the metal-based electrode comprises Au(111), Cu(111), Ni(111), or Pd(111).
5. The method of claim 1 , wherein the patterning comprises:
heating the metal-based electrode to an annealing temperature in a range of about 500 K to about 1500 K under a reducing atmosphere;
cooling the electrode; and
immersing the electrode in the melamine solution.
6. The method of claim 5 , wherein the annealing temperature is in a range of about 1000 K to about 1200 K.
7. The method of claim 5 , wherein the reducing atmosphere comprises hydrogen gas.
8. The method of claim 5 , wherein the reducing atmosphere comprises hydrogen gas and an inert gas.
9. The method of claim 8 , wherein the inert gas comprises He, Ne, Ar, or Na.
10. The method of claim 5 , where the electrode is cooled to about ambient temperature.
11. The method of claim 5 , wherein the solution comprises an aqueous solution of melamine.
12. The method of claim 11 , wherein the solution is at a solution temperature from about 300 K to about 350 K.
13. The method of claim 11 , wherein the concentration of the melamine in the solution is in a range from of 1 μM to about 100 μM.
14. The method of claim 5 , wherein the solution is evaporated from the metal-based electrode.
15. An electrode, comprising:
a patterned metal-based substrate, a surface of the patterned metal-based substrate comprising metal sites blocked with melamine molecules and metal sites which are not blocked such that the metal-based electrode selectively adsorbs O 2 instead of at least one of sulfate, phosphate, or sulphonate,
wherein a range of 20% to 40% of the metal sites are blocked with melamine molecules.
16. The electrode of claim 15 , wherein the metal-based substrate comprises Pt, Pd, Ir, or Rh, or a Pt alloy with one or more of Co, Ni, Fe, Ti, Cr, V, or Mn.
17. The electrode of claim 15 , wherein the metal-based substrate comprises Pt(100), Pt(111), Pt(1099), polycrystalline Pt, Au(111), Cu(111), Ni(111), or Pd(111).
18. The electrode of claim 15 , wherein the metal-based substrate comprises a nanoparticle comprising platinum.
19. The electrode of claim 15 , further comprising:
a sulfonated tetrafluoroethylene based fluoropolymer-copolymer coated on the metal-based substrate.
20. A fuel cell comprising the electrode of claim 15 .