Core-shell catalyst for oxygen reduction reaction, and method of designing catalyst

Patent metadata

Field	Value
Publication number	US-2023395818-A1
Application number	US-202118268899-A
Country	US
Kind code	A1
Filing date	Dec 13, 2021
Priority date	Dec 22, 2020
Publication date	Dec 7, 2023
Grant date	—

Abstract

A catalyst for an oxygen reduction reaction containing catalyst particles having a shell-core structure containing a PtCo alloy or a PtCoMn alloy as a core, and platinum as a shell layer. A specific plane of a face-centered cubic lattice is formed by a plurality of platinum atoms contained in the shell layer, and a lattice constant of the plane of the face-centered cubic lattice on the catalyst particle surface is 3.70 Å or more and 4.05 Å or less (in a PtCo alloy), or 3.870 Å or more and 4.10 Å or less (in a PtCoMn alloy). A catalyst design method includes a step of calculating, with respect to an orientation plane such as the plane formed by platinum atoms of the shell layer, adsorption energies for an oxygen molecule, an OH group and a water molecule by first-principles calculation based on density functional theory.

First claim

1 . A catalyst for an oxygen reduction reaction, comprising catalyst particles having a core-shell structure containing a PtCo alloy as a core, and platinum as a shell layer,
wherein a plurality of platinum atoms contained in the shell layer form a (111) plane of a face-centered cubic lattice, and a lattice constant of the (111) plane of the face-centered cubic lattice on a surface of the catalyst particle is 3.70 Å or more and 4.05 Å or less.

2 . The catalyst according to claim 1 , wherein a lattice constant of a (111) plane of the face-centered cubic lattice formed by platinum atoms present inside the catalyst particles is smaller than a lattice constant of a (111) plane of the face-centered cubic lattice on a surface of the catalyst particle.

3 . The catalyst according to claim 1 , wherein a lattice constant of a (111) plane of the face-centered cubic lattice formed by platinum atoms present inside the catalyst particles is 3.55 Å or more and 3.95 Å or less.

4 . The catalyst according to claim 1 , wherein the PtCo alloy contained in the core is PtCo x , wherein 0.14≤x≤0.33.

5 . A catalyst for an oxygen reduction reaction, comprising catalyst particles having a core-shell structure containing a PtCoMn alloy as a core, and platinum as a shell layer,
wherein a plurality of platinum atoms contained in the shell layer form a (111) plane of a face-centered cubic lattice, and a lattice constant of the (111) plane of the face-centered cubic lattice on a surface of the catalyst particles is 3.870 Å or more and 4.10 Å or less.

6 . The catalyst according to claim 5 , wherein a lattice constant of a (111) plane of the face-centered cubic lattice formed by platinum atoms present inside the catalyst particles is smaller than a lattice constant of a (111) plane of the face-centered cubic lattice on the surface of the catalyst particles.

7 . The catalyst according to claim 5 , wherein a lattice constant of a (111) plane of the face-centered cubic lattice formed by platinum atoms present inside the catalyst particles is 3.70 Å or more and 4.05 Å or less.

8 . The catalyst according to claim 5 , wherein the PtCoMn alloy contained in the core is PtCo y Mn z , wherein 0.06≤y≤0.39 and 0.04≤z≤0.33.

9 . The catalyst according to claim 1 , wherein an absolute value of an adsorption energy in an adsorption site having a maximum oxygen atom adsorption energy is less than 1.0 eV.

10 . The catalyst according to claim 1 , wherein an absolute value of an adsorption energy in an adsorption site having a maximum oxygen molecule adsorption energy is less than 0.5 eV.

11 . The catalyst according to claim 1 , wherein an absolute value of an adsorption energy in an adsorption site having a maximum OH group adsorption energy is less than 2.3 eV.

12 . The catalyst according to claim 1 , wherein an absolute value of an adsorption energy in an adsorption site having a maximum water molecule adsorption energy is less than 0.19 eV.

13 . The catalyst according to claim 1 , wherein the catalyst particle is supported on a carbon fine powder carrier.

14 . The catalyst according to claim 1 for use in a polymer electrolyte fuel cell, wherein a supporting density of the catalyst particles in the entire catalyst is 20 to 70% by mass.

15 . A method for designing a catalyst for an oxygen reduction reaction, the catalyst comprising catalyst particles having a core-shell structure containing, as a core, an alloy consisting of platinum and one or more alloy elements, and platinum as a shell layer, the method comprising:
a step of selecting at least any one of orientation planes of a (111) plane, a (001) plane, and a (110) plane as arrangement of a plurality of platinum atoms contained in the shell layer; a step of creating an adsorption model for an oxygen molecule, an OH group generation model, and a water molecule generation and desorption model with respect to the selected orientation plane of platinum; and a step of calculating an adsorption energy for the oxygen molecule, an OH group adsorption energy, and a water molecule adsorption energy by first-principles calculation based on density functional theory, wherein the alloy elements are selected based on calculation results of the adsorption energy, the OH group adsorption energy, and the water molecule adsorption energy.

16 . The catalyst according to claim 2 , wherein a lattice constant of a (111) plane of the face-centered cubic lattice formed by platinum atoms present inside the catalyst particles is 3.55 Å or more and 3.95 Å or less.

17 . The catalyst according to claim 2 , wherein the PtCo alloy contained in the core is PtCo x , wherein 0.14≤x≤0.33.

18 . The catalyst according to claim 3 , wherein the PtCo alloy contained in the core is PtCo x , wherein 0.14≤x≤0.33.

19 . The catalyst according to claim 6 , wherein a lattice constant of a (111) plane of the face-centered cubic lattice formed by platinum atoms present inside the catalyst particles is 3.70 Å or more and 4.05 Å or less.

20 . The catalyst according to claim 6 , wherein the PtCoMn alloy contained in the core is PtCo y Mn z , wherein 0.06≤y≤0.39 and 0.04≤z≤0.33.

Assignees

• Tanaka Precious Metal Ind
• National Institute Of Tech

Inventors

• Ishida Minoru
• Matsutani Koichi
• Nakanishi Hiroshi
• Kasai Hideaki
• Chantaramolee Bhume
• Aspera Susan Menez

Classifications

• G16C20/10

  Analysis or design of chemical reactions, syntheses or processes · CPC title

• G16C60/00

  Computational materials science, i.e. ICT specially adapted for investigating the physical or chemical properties of materials or phenomena associated with their design, synthesis, processing, characterisation or utilisation · CPC title

• C22C1/0466

  Alloys based on noble metals · CPC title

• B22F9/24

  starting from liquid metal compounds, e.g. solutions · CPC title

• B22F1/054

  Nanosized particles · CPC title