Catalyst support particle structures
Electrocatalysts for use in fuel cell membrane electrode assemblies include a support substrate comprising a metal oxide nanotube having an internal support surface and conductive metal oxide particles impregnated on the internal support surface. Fuel cell electrodes are produced using the electrocatalyst coated on a gas diffusion layer.
1. An electrocatalyst comprising:
a support substrate comprising:
a metal oxide nanotube consisting of titanium dioxide having an internal support surface and an exterior support surface; and
conductive metal oxide particles consisting of ruthenium dioxide and impregnated only on the internal support surface; and
active catalyst particles deposited only on the exterior support surface, wherein the conductive metal oxide particles and the active catalyst particles are different materials.
2. The electrocatalyst of claim 1 , wherein the conductive metal oxide particles are evenly distributed across the internal support surface.
3. The electrocatalyst of claim 1 , wherein the conductive metal oxide particles are concentrated on one longitudinal end of the metal oxide nanotube.
4. The electrocatalyst of claim 1 , wherein the active catalyst particles are platinum.
5. The electrocatalyst of claim 1 , wherein the metal oxide nanotube has a triangular cross section.
6. The electrocatalyst of claim 5 , wherein the active catalyst particles are deposited only on corners of the exterior support surface of the metal oxide nanotube.
7. The electrocatalyst support of claim 1 , wherein the metal oxide nanotube has a square cross section.
8. The electrocatalyst of claim 7 , wherein the active catalyst particles are deposited only on corners of the exterior support surface of the metal oxide nanotube.
9. An electrode comprising:
the electrocatalyst of claim 1 ; and
a gas diffusion layer on which the electrocatalyst is coated.
10. The electrode of claim 9 , wherein the metal oxide nanotube is a titanium dioxide nanotube and the conductive metal oxide is ruthenium dioxide.
11. The electrode of claim 9 , wherein the electrocatalyst is coated on the gas diffusion layer such that the metal oxide nanotubes extend from the gas diffusion layer in a parallel standing arrangement.
12. The electrode of claim 11 , wherein the conductive metal oxide is concentrated on the internal support surface at an end of the metal oxide nanotube opposite the gas diffusion layer.
13. The electrode of claim 9 , wherein the electrocatalyst is coated on the gas diffusion layer such that the metal oxide nanotubes are randomly positioned on the gas diffusion layer.
14. The electrode of claim 13 , wherein the conductive metal oxide is evenly distributed on the internal support surface of the metal oxide nanotube.
15. The electrode of claim 9 wherein the metal oxide nanotube has one of a triangular cross section and a square cross section.
16. The electrode of claim 15 , wherein the active catalyst particles are deposited only on corners of the exterior support surface of the metal oxide nanotube.
17. An electrocatalyst comprising:
a support substrate comprising:
a metal oxide nanotube having an internal support surface and an exterior support surface, wherein the metal oxide nanotube has a triangular cross section or a square cross section; and
conductive metal oxide particles impregnated only on the internal support surface; and
active catalyst particles deposited only on the exterior support surface, wherein the conductive metal oxide particles and the active catalyst particles are different materials.