Catalyst, catalyst for water electrolysis cell, water electrolysis cell, water electrolysis device, and method for producing catalyst

Patent metadata

Field	Value
Publication number	US-2023121007-A1
Application number	US-202218067775-A
Country	US
Kind code	A1
Filing date	Dec 19, 2022
Priority date	Jul 17, 2020
Publication date	Apr 20, 2023
Grant date	—

Abstract

A catalyst includes a layered double hydroxide and a metal particle. The layered double hydroxide includes ions of at least two transition metals. The metal particle includes at least one transition metal. The metal particle has a surface coated with the layered double hydroxide.

First claim

What is claimed is:

1 . A catalyst comprising:
a layered double hydroxide including ions of at least two transition metals; and a metal particle including at least one transition metal, wherein the metal particle has a surface coated with the layered double hydroxide.

2 . The catalyst according to claim 1 , wherein a ratio R2/R1 is greater than or equal to 0.87 and less than or equal to 1.20, the ratio R2/R1 being a ratio of R2 to R1, where
R1 is defined as a ratio of a mass of the metal particle to a mass of the layered double hydroxide, the mass of the metal particle being an amount used in preparation of the catalyst, the mass of the layered double hydroxide being a mass of the layered double hydroxide in an instance in which all ions of transition metals used in the preparation of the catalyst contribute to formation of the layered double hydroxide, the transition metals being identical to the at least two transition metals, and R2 is defined as a ratio of a mass of the metal particle in the catalyst to a mass of the layered double hydroxide in the catalyst.

3 . The catalyst according to claim 1 , further comprising a coating layer that is provided on the surface of the metal particle and that includes the layered double hydroxide, wherein the coating layer has an average thickness of less than or equal to 100 nm.

4 . The catalyst according to claim 1 , wherein the layered double hydroxide has a crystallite size of less than or equal to 10 nm.

5 . The catalyst according to claim 1 , wherein the layered double hydroxide includes a multidentate ligand.

6 . The catalyst according to claim 5 , wherein the multidentate ligand includes at least one selected from the group consisting of acetylacetone and a citric acid salt.

7 . The catalyst according to claim 1 , wherein the ions of the at least two transition metals include ions of at least two transition metals selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, W, and Ru.

8 . The catalyst according to claim 7 , wherein the ions of the at least two transition metals include an ion of at least one transition metal selected from the group consisting of Ni and Fe.

9 . The catalyst according to claim 1 , wherein the metal particle includes Ni.

10 . The catalyst according to claim 1 , wherein the metal particle has an average particle diameter of less than or equal to 50 nm.

11 . A catalyst for a water electrolysis cell, comprising the catalyst according to claim 1 .

12 . A water electrolysis cell comprising:
a positive electrode including the catalyst for a water electrolysis cell according to claim 11 ; a negative electrode; and an electrolyte.

13 . A water electrolysis cell comprising:
a positive electrode; a negative electrode including the catalyst for a water electrolysis cell according to claim 11 ; and an electrolyte.

14 . A water electrolysis device comprising:
the water electrolysis cell according to claim 12 ; and a voltage applicator that applies a voltage between the positive electrode and the negative electrode, the voltage applicator being connected to the positive electrode and the negative electrode.

15 . A method for producing a catalyst, the method comprising:
adding a multidentate ligand to prepare an aqueous solution that includes a metal particle, the multidentate ligand, and ions of at least two transition metals, the metal particle including a transition metal that is the same as at least one of the at least two transition metals; and converting the aqueous solution into an alkaline aqueous solution at ambient temperature.

16 . The method for producing a catalyst according to claim 15 , wherein
the catalyst includes a layered double hydroxide and the metal particle, and a ratio R2/R1 is greater than or equal to 0.87 and less than or equal to 1.20, the ratio R2/R1 being a ratio of R2 to R1, where R1 is defined as a ratio of a mass of the metal particle to a mass of the layered double hydroxide, the mass of the metal particle being an amount added to the aqueous solution, the mass of the layered double hydroxide being a mass of the layered double hydroxide in an instance in which all of the ions of the at least two transition metals in the aqueous solution contribute to formation of the layered double hydroxide, and R2 is defined as a ratio of a mass of the metal particle in the catalyst to a mass of the layered double hydroxide in the catalyst.

17 . The method for producing a catalyst according to claim 15 , further comprising increasing a pH of the alkaline aqueous solution.

18 . The method for producing a catalyst according to claim 15 , wherein the ions of the at least two transition metals include ions of at least two transition metals selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, W, and Ru.

19 . The method for producing a catalyst according to claim 18 , wherein the ions of the at least two transition metals include an ion of at least one transition metal selected from the group consisting of Ni and Fe.

20 . The method for producing a catalyst according to claim 15 , wherein the metal particle includes Ni.

21 . The method for producing a catalyst according to claim 15 , wherein the ions of the at least two transition metals and the multidentate ligand form complexes having a solubility in water at 20° C. to 25° C. of greater than or equal to 2 g/liter.

22 . The method for producing a catalyst according to claim 15 , wherein the multidentate ligand includes at least one selected from the group consisting of acetylacetone and a citric acid salt.

23 . The method for producing a catalyst according to claim 15 , wherein a ratio of a concentration of the multidentate ligand in the aqueous solution to a total concentration of the ions of the at least two transition metals in the aqueous solution is less than or equal to 0.4.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Koshikawa Hiroyuki
• Murase Hideaki
• Hayashi Takao
• Suzuka Michio
• Shiraishi Seigo

Classifications

• C25B11/052

  Electrodes comprising one or more electrocatalytic coatings on a substrate · CPC title

• C25B11/054

  Electrodes comprising electrocatalysts supported on a carrier · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title

• C25B11/077

  the compound being a non-noble metal oxide · CPC title

• B22F1/16

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title