# US 9,435,043 B2 · Oxygen evolution reaction catalysis

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- Number: US 9,435,043 B2
- Document ID: US9435043B2
- Status: Granted
- Kind: B2
- Application number: 14/569,497
- Filed: 2014-12-12
- Published: 2015-10-15
- Granted: 2016-09-06
- Earliest claimed: 2014-04-14
- Assignees: California Institute of Technology; The Regents of the University of California
- Applicants: The California Institute of Technology; The Regents of the University of California
- Inventors: Joel A. Haber; Jian Jin; Chengxiang Xiang; John M. Gregoire; Ryan J. Jones; Dan W. Guevarra; Aniketa A. Shinde
- Web page: https://patentgrep.com/patent/US9435043B2

## CPC

- C25B 11/077: the compound being a non-noble metal oxide
- C25B 1/02: Hydrogen or oxygen
- C25C 7/02: Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof
- H01M 4/9016: {Oxides, hydroxides or oxygenated metallic salts}
- Y02E 60/50: Fuel cells
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- C25C: PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

## Claims

### Claim 1

An Oxygen Evolution Reaction (OER) catalyst, comprising:
a metal oxide that includes oxygen, cerium, and one or more second metals, the cerium being between 10 and 80 molar % of the metals in the metal oxide and wherein the metal oxide provides an Oxygen Evolution Reaction (OER) Tafel slope greater than 50 mV/decade.

### Claim 2 (depends on 1)

The OER catalyst of claim 1, wherein the one or more second metals are selected from the group consisting of transition metals, post transition metals and lanthanides.

### Claim 3 (depends on 1)

The OER catalyst of claim 1, wherein the one or more second metals are transition metals.

### Claim 4 (depends on 1)

The OER catalyst of claim 1, wherein the metal oxide is represented by (M1vM2wM3yCez)Ox where M1 represents a first metal, M2 represents a second metal, M3 represents a third metal, v+w+y+z=1, v is greater than or equal to 0 and less than 1, w is greater than or equal to 0 and less than 1, y is greater than 0 and less than 1, and z is greater than 0, and x is greater than 0.

### Claim 5 (depends on 4)

The OER catalyst of claim 4, wherein z is greater than or equal to 0.1 and less than or equal to 0.8.

### Claim 6 (depends on 4)

The OER catalyst of claim 4, wherein z is greater than or equal to 0.3 and less than or equal to 0.6.

### Claim 7 (depends on 4)

The OER catalyst of claim 4, wherein M3 is selected from the group consisting of cobalt, nickel and iron,
M1 and M2 are different,
M1 and M2 are selected from the group consisting of transition metals, post transition metals and lanthanides, and
v is greater than 0 and w is greater than 0.

### Claim 8 (depends on 7)

The OER catalyst of claim 7, wherein M1 and M2 are different from M3,
M1 and M2 are selected from the group consisting of Ni, Mn, Cu, Zn, Sn, Ta, Y, Gd, La, and Fe, and
v is greater than 0 and w is greater than 0.

### Claim 9 (depends on 4)

The OER catalyst of claim 4, wherein M1, M2, and M3 are different,
M2 and M3 are each selected from the group consisting of cobalt, nickel and iron,
M1 is selected from the group consisting of transition metals, post transition metals and lanthanides, and
v is greater than 0 and w is greater than 0.

### Claim 10 (depends on 4)

The OER catalyst of claim 4, wherein M1, M2, and M3 are different,
M2 and M3 are each selected from the group consisting of cobalt, nickel and iron,
M1 is selected from the group consisting of Ni, Mn, Cu, Zn, Sn, Ta, Y, Gd, La, and Fe, and
v is greater than 0 and w is greater than 0.

### Claim 11 (depends on 10)

The OER catalyst of claim 10, wherein M1 represent La.

### Claim 12 (depends on 10)

The OER catalyst of claim 10, wherein the metal oxide is represented by (FevNiwCoyCez)Ox and v is greater than 0 and w is greater than 0.

### Claim 13 (depends on 1)

The OER catalyst of claim 1, wherein the metal oxide has an opacity less than 50% per 100 nm thickness when averaged over the visible spectrum.

### Claim 14 (depends on 1)

The OER catalyst of claim 1, wherein the metal oxide is included in an electrode.

### Claim 15 (depends on 14)

The OER catalyst of claim 14, wherein the electrode is included in an oxygen evolution system where the Oxygen Evolution Reaction (OER) occurs at the electrode.

### Claim 16 (depends on 15)

The OER catalyst of claim 15, wherein the metal oxide is included in an electrode at which the Oxygen Evolution Reaction occurs.

### Claim 17 (depends on 16)

The OER catalyst of claim 16, wherein the electrode is included in an Oxygen Evolution Reaction (OER) system where the electrode is exposed to an environment with a pH less than 3.

### Claim 18

An Oxygen Evolution Reaction (OER) catalyst, comprising:
a metal oxide that includes three or more metals selected from the group consisting of Mn, Co, Ta, Sn, and Sb and wherein the metal oxide provides an Oxygen Evolution Reaction (OER) Tafel slope greater than 50 mV/decade.

### Claim 19 (depends on 18)

The OER catalyst of claim 18, wherein the metal oxide includes oxygen, Mn, Co, Ta, and Sb.