# US 2021/0242471 A1 · Catalyst, catalyst layer, membrane-electrode assembly, electrochemical device, and method for producing catalyst

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- Number: US 2021/0242471 A1
- Document ID: US20210242471A1
- Status: Published application
- Kind: A1
- Application number: 17/232,385
- Filed: 2021-04-16
- Published: 2021-08-05
- Earliest claimed: 2019-09-27
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: HARUHIKO SHINTANI; NOBUHIRO MIYATA; TOMOKATSU WADA
- Web page: https://patentgrep.com/patent/US20210242471A1

## CPC

- H01M 4/926: {on carbon or graphite}
- B01J 21/185: {Carbon nanotubes (carbon nanotubes per se C01B32/15)}
- B01J 23/42: Platinum
- B01J 23/75: Cobalt
- B01J 35/45: Nanoparticles
- B01J 35/638: {more than 1.0 ml/g}
- B01J 35/647: {2-50 nm}
- B01J 37/0207: {Pretreatment of the support}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/16: Reducing
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- H01M 4/8657: {layered}
- H01M 4/8842: {Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor}
- H01M 4/8882: {Heat treatment, e.g. drying, baking}
- H01M 4/921: {Alloys or mixtures with metallic elements}
- H01M 8/1004: characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence)
- H01M 8/1067: characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
- H01M 2004/028: {Positive electrodes}
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- Y02E 60/10: Energy storage using batteries
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A catalyst includes a mesoporous material and catalytic metal particles supported at least within the mesoporous material and containing platinum and a metal different from platinum. The mesoporous material has mesopores with a mode radius of 1 to 25 nm and a pore volume of 1.0 to 3.0 cm3/g before supporting of the catalytic metal particles, and has an average particle size of greater than or equal to 200 nm. A molar ratio of the metal different from platinum and contained in the catalytic metal particles relative to all metals contained in the catalytic metal particles is greater than or equal to 0.25, and among the catalytic metal particles, a volume ratio of catalytic metal particles having a particle size of greater than or equal to 20 nm is less than or equal to 10%.

## Claims

### Claim 1

A catalyst comprising:
a mesoporous material; and
catalytic metal particles supported at least within the mesoporous material and containing platinum and a metal different from platinum,
wherein the mesoporous material has mesopores with a mode radius of greater than or equal to 1 nm and less than or equal to 25 nm and a pore volume of greater than or equal to 1.0 cm3/g and less than or equal to 3.0 cm3/g before supporting of the catalytic metal particles, and has an average particle size of greater than or equal to 200 nm,
a molar ratio of the metal different from platinum and contained in the catalytic metal particles relative to all metals contained in the catalytic metal particles is greater than or equal to 0.25, and among the catalytic metal particles, a volume ratio of catalytic metal particles having a particle size of greater than or equal to 20 nm is less than or equal to 10%.

### Claim 2 (depends on 1)

The catalyst according to claim 1, wherein a molar ratio of the metal different from platinum and contained in the catalytic metal particles having a particle size of greater than or equal to 20 nm relative to all metals contained in the catalytic metal particles having a particle size of greater than or equal to 20 nm is larger than a molar ratio of the metal different from platinum and contained in catalytic metal particles having a particle size of less than 20 nm relative to all metals contained in the catalytic metal particles having a particle size of less than 20 nm.

### Claim 3 (depends on 1)

The catalyst according to claim 1, wherein the metal different from platinum is cobalt.

### Claim 4 (depends on 1)

The catalyst according to claim 1, wherein the mode radius of the mesopores is greater than or equal to 3 nm and less than or equal to 6 nm.

### Claim 5 (depends on 1)

The catalyst according to claim 1, wherein the mesoporous material comprises mesoporous carbon.

### Claim 6 (depends on 1)

A catalyst layer comprising the catalyst according to claim 1 and an ionomer.

### Claim 7 (depends on 6)

The catalyst layer according to claim 6, comprising at least one of carbon black or carbon nanotube.

### Claim 8 (depends on 7)

The catalyst layer according to claim 7, wherein the carbon black is Ketjenblack.

### Claim 9 (depends on 6)

A membrane-electrode assembly comprising
a polymer electrolyte membrane;
a fuel electrode disposed on a first main surface of the polymer electrolyte membrane; and
an air electrode disposed on a second main surface of the polymer electrolyte membrane,
wherein the air electrode includes the catalyst layer according to claim 6.

### Claim 10 (depends on 9)

An electrochemical device comprising the membrane-electrode assembly according to claim 9.

### Claim 11

A method for producing a catalyst, comprising:
supporting platinum within mesopores of a mesoporous material having an average particle size of greater than or equal to 200 nm, the mesopores having a mode radius of greater than or equal to 1 nm and less than or equal to 25 nm and a pore volume of greater than or equal to 1.0 cm3/g and less than or equal to 3.0 cm3/g;
subjecting the mesoporous material supporting platinum within the mesopores to water vapor adsorption treatment; and
supporting a metal different from platinum within the mesopores of the mesoporous material that has been subjected to the water vapor adsorption treatment.

### Claim 12 (depends on 11)

The method for producing a catalyst according to claim 11, wherein the water vapor adsorption treatment includes exposing the mesoporous material supporting platinum within the mesopores to an environment at a higher humidity than a relative humidity of outside air.

### Claim 13 (depends on 11)

The method for producing a catalyst according to claim 11, wherein the mesoporous material that has been subjected to the water vapor adsorption treatment is impregnated with a precursor solution of the metal different from platinum to prepare a suspension, and the suspension is subjected to reduction treatment to support the metal different from platinum within the mesopores.

### Claim 14 (depends on 13)

The method for producing a catalyst according to claim 13, wherein a solvent of the precursor solution of the metal different from platinum is water.

### Claim 15 (depends on 13)

The method for producing a catalyst according to claim 13, wherein the precursor solution of the metal different from platinum is adjusted such that a molar ratio of the metal different from platinum relative to all metals contained in the suspension becomes greater than or equal to 0.38.

### Claim 16 (depends on 13)

The method for producing a catalyst according to claim 13, wherein, in the reduction treatment, at least one reducing agent selected from the group consisting of hydrazine and sodium borohydride is used.

### Claim 17 (depends on 13)

The method for producing a catalyst according to claim 13, comprising heat treatment of the mesoporous material in which the metal different from platinum is supported within the mesopores by the reduction treatment.

### Claim 18 (depends on 17)

The method for producing a catalyst according to claim 17, wherein the heat treatment includes heating the mesoporous material at a temperature higher than or equal to 700° C.

### Claim 19 (depends on 13)

The method for producing a catalyst according to claim 13, wherein the metal different from platinum is cobalt.

### Claim 20 (depends on 11)

The method for producing a catalyst according to claim 11, wherein the mesoporous material comprises mesoporous carbon.