Mixed metal oxide compounds and electrocatalytic compositions, devices and processes using the same
A metal oxide compound of formula (I): Mn x M y Ru 1-(x+y) O 2 (I) is a single phase rutile-type structure, where M is Co, Ni, or Fe, or a combination thereof, x>0, y≥0, and 0.02≤(x+y)≤0.30. Related electro-catalysts, devices, and processes are also provided.
1. A metal oxide compound of formula (I′):
Mn x M y Ru 1-(x+y) O 2 (I′),
wherein the compound is a single phase rutile-type structure, and wherein
M is selected from the group consisting of Co, Ni, and Fe, and combinations thereof;
x>0;
y>0; and
0.02≤(x+y)≤0.30.
2. The metal oxide compound according to claim 1 , wherein 0.02<x<0.28 and 0<y<0.20.
3. The metal oxide compound according to claim 1 , wherein said compound is a quaternary compound and M is selected from Co, Ni, and Fe.
4. The metal oxide compound according to claim 3 , wherein M is Co.
5. The metal oxide compound according to claim 3 , wherein M is Ni.
6. The metal oxide compound according to claim 3 , wherein M is Fe.
7. The metal oxide compound according to claim 1 , wherein 0.10≤x≤0.20.
8. The metal oxide compound according to claim 1 , wherein 0<y<0.15.
9. The metal oxide compound according to claim 1 , wherein all Mn atoms present in the compound are atomically incorporated into the rutile-type structure.
10. The metal oxide compound according to claim 1 , wherein the source of the Mn present in the compound is Mn 2 O 3 or beta “β” phase MnO 2 .
11. An electro-catalyst for use under alkaline conditions comprising a metal oxide compound according to formula (I′):
Mn x M y Ru 1-(x+y) O 2 (I′),
wherein the compound is a single phase rutile-type structure, and wherein
M is selected from the group consisting of Co, Ni, and Fe, and combinations thereof;
x>0;
y≥0; and
0.02≤(x+y)≤0.30.
12. The electro-catalyst according to claim 11 , wherein Mn atoms are incorporated into the structure of RuO 2 , and said electro-catalyst does not comprise MnO 2 by itself.
13. The electro-catalyst according to claim 11 , wherein said electro-catalyst does not comprise a rare earth metal.
14. A film comprising the metal oxide compound of formula (I) according to claim 11 .
15. The film according to claim 14 , having a thickness of 150 to 400 nm.
16. A solid particle comprising the metal oxide compound according to claim 11 .
17. A membrane electrode assembly (MEA) comprising the metal oxide compound of formula (I) according to claim 11 .
18. An alkaline fuel cell catalyst comprising the electro-catalyst according to claim 11 .
19. An electro-catalytic process performed at a pH>7, wherein said process comprises performing an oxygen reduction reaction (ORR) or an oxygen evolution reaction (OER) in the presence of the electro-catalyst according to claim 11 .
20. A cathode or an air battery comprising the metal oxide compound of formula (I) according to claim 11 .