Method for producing junction photocatalyst, and junction photocatalyst

Patent metadata

Field	Value
Publication number	US-2025196120-A1
Application number	US-202318842921-A
Country	US
Kind code	A1
Filing date	Feb 28, 2023
Priority date	Mar 1, 2022
Publication date	Jun 19, 2025
Grant date	—

Abstract

The present invention provides a method for producing a heterojunction photocatalyst having higher catalytic activity than that of conventional heterojunction photocatalysts, and a heterojunction photocatalyst. A method for producing a heterojunction photocatalyst having a solid state mediator between a hydrogen-evolution photocatalyst and an oxygen-evolution photocatalyst, which includes the following step 1: step 1: a step of joining the solid state mediator onto the oxygen-evolution photocatalyst by at least one method selected from the group consisting of a photoelectrodeposition method, an impregnation supporting method, and a precipitation method, in each of which an organic carboxylic acid compound and a solid state mediator or a precursor of the solid state mediator are used.

First claim

1 . A method for producing a heterojunction photocatalyst having a solid state mediator between a hydrogen-evolution photocatalyst and an oxygen-evolution photocatalyst, the method comprising step 1 below:
step 1: joining the solid state mediator onto the oxygen-evolution photocatalyst by at least one method selected from the group consisting of a photoelectrodeposition method, an impregnation supporting method, and a precipitation method, in each of which an organic carboxylic acid compound and the solid state mediator or a precursor of the solid state mediator are used.

2 . The method for producing a heterojunction photocatalyst according to claim 1 , wherein the step 1 is performed by the photoelectrodeposition method by irradiating a dispersion containing the oxygen-evolution photocatalyst in addition to the organic carboxylic acid compound and the solid state mediator or the precursor of the solid state mediator with light.

3 . The method for producing a heterojunction photocatalyst according to claim 1 , wherein the organic carboxylic acid compound is at least one selected from the group consisting of an ether carboxylate, a fatty acid, a hydroxymonocarboxylic acid, and a polycarboxylic acid.

4 . The method for producing a heterojunction photocatalyst according to claim 1 , wherein
the organic carboxylic acid compound includes an ether carboxylate, and the solid state mediator includes gold.

5 . The method for producing a heterojunction photocatalyst according to claim 1 , further comprising steps 2 to 4 below, provided that the steps 2 and 3 are performed in a random order:
step 2: introducing an ionic group into the solid state mediator to obtain the oxygen-evolution photocatalyst to which the solid state mediator having the ionic group is joined; step 3: introducing an ionic polymer having a charge opposite to a charge of the ionic group into the hydrogen-evolution photocatalyst; and step 4: mixing the oxygen-evolution photocatalyst obtained in the step 2 to which the solid state mediator having the ionic group is joined with the hydrogen-evolution photocatalyst obtained in the step 3 into which the ionic polymer is introduced.

6 . The method for producing a heterojunction photocatalyst according to claim 1 , further comprising steps 2′, 3′, and 4′ below, provided that the steps 2′ and 3′ are performed in a random order:
step 2′: introducing an ionic group into the solid state mediator and further reacting the ionic group with a first ionic polymer having a charge opposite to a charge of the ionic group to obtain the oxygen-evolution photocatalyst to which the solid state mediator having the first ionic polymer is joined;
step 3′: introducing a second ionic polymer having a charge opposite to the charge of the first ionic polymer into the hydrogen-evolution photocatalyst; and
step 4′: mixing the oxygen-evolution photocatalyst obtained in the step 2′ to which the solid state mediator having the first ionic polymer is joined with the hydrogen-evolution photocatalyst obtained in the step 3′ into which the second ionic polymer is introduced.

7 . The method for producing a heterojunction photocatalyst according to claim 5 , wherein a thiol compound having an ionic group is used in introducing the ionic group into the solid state mediator in the step 2.

8 . The method for producing a heterojunction photocatalyst according to claim 1 , wherein a coverage of the solid state mediator to an electrons collecting surface area of the oxygen-evolution photocatalyst is 40% or more.

9 . A heterojunction photocatalyst, comprising:
a solid state mediator between a hydrogen-evolution photocatalyst and an oxygen-evolution photocatalyst, wherein a coverage of the solid state mediator to an electrons collecting surface area of the oxygen-evolution photocatalyst is 40% or more.

10 . The heterojunction photocatalyst according to claim 9 , wherein a heterojunction selectivity of the solid state mediator to the electrons collecting surface of the oxygen-evolution photocatalyst is 60% or more.

11 . The heterojunction photocatalyst according to claim 9 , wherein the solid state mediator and the hydrogen-evolution photocatalyst are joined to each other via an ionic polymer.

12 . The heterojunction photocatalyst according to claim 9 , wherein the solid state mediator has an ionic group, and the solid state mediator and the hydrogen-evolution photocatalyst are joined to each other via an ionic polymer having a charge opposite to a charge of the ionic group.

13 - 19 . (canceled)

20 . A photocatalyst composite, comprising:
the heterojunction photocatalyst according to claim 9 on a substrate.

21 . (canceled)

22 . A method for producing hydrogen, the method comprising:
irradiating the heterojunction photocatalyst according to claim 9 with light in the presence of water or an alcohol.

23 . A method for producing oxygen, the method comprising:
irradiating the heterojunction photocatalyst according to claim 9 with light in the presence of water or an alcohol.

Assignees

• Kao Corp

Inventors

• Miyasato Ryo
• Nakajima Kana
• Shiraishi Yohei

Classifications

• C01B13/0207

  Water · CPC title

• C01B3/042

  Decomposition of water (by electrolysis of water C25B1/04) · CPC title

• B01J37/348

  Electrochemical processes, e.g. electrochemical deposition or anodisation · CPC title

• B01J37/30

  Ion-exchange · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title