Photocatalyst material and method for producing same

Patent metadata

Field	Value
Publication number	US-2018214858-A1
Application number	US-201615745085-A
Country	US
Kind code	A1
Filing date	Jul 29, 2016
Priority date	Jul 31, 2015
Publication date	Aug 2, 2018
Grant date	—

Abstract

A photocatalytic member comprises a base and a photocatalytic layer fixed on the base. The photocatalytic layer comprises first photocatalyst particles being visible light responsive photocatalyst particles for hydrogen generation, second photocatalyst particles being visible light responsive photocatalyst particles for oxygen generation, and conductive particles which are provided between the first photocatalyst particle and the second photocatalyst particle, have Fermi level at a negative position relative to an electronic energy level at the upper end of the valence band of the first photocatalyst particle and at a positive position relative to an electronic energy level at the bottom end of the conduction band of the second photocatalyst particle, and are able to store an electron and a hole. In the photocatalytic layer, the conductive particles are located to be coupled to both the first photocatalyst particles and the second photocatalyst particles.

First claim

1 . A photocatalytic member comprising a base and a photocatalytic layer fixed on the base, wherein the photocatalytic layer comprises
first photocatalyst particles being visible light responsive photocatalyst particles for hydrogen generation, second photocatalyst particles being visible light responsive photocatalyst particles for oxygen generation, and conductive particles which are provided between the first photocatalyst particle and the second photocatalyst particle, have Fermi level at a negative position relative to an electronic energy level at the upper end of the valence band of the first photocatalyst particle and at a positive position relative to an electronic energy level at the bottom end of the conduction band of the second photocatalyst particle, and are able to store an electron and a hole, and wherein the conductive particles are located to be coupled to both the first photocatalyst particles and the second photocatalyst particles.

2 . The photocatalytic member according to claim 1 , wherein
the conductive particle has a first region, a second region and a third region on a surface thereof; and is in contact with the first photocatalyst particle in the first region, is in contact with the second photocatalyst particle in the second region, and is not in contact with either of the first or the second photocatalyst particles in the third region.

3 . The photocatalytic member according to claim 1 , wherein the conductive particle has a conductivity of 0.1 Scm −1 or more.

4 . The photocatalytic member according to claim 1 , wherein the average primary particle diameter of the conductive particles is smaller than the average primary particle diameter of the first photocatalyst particles, and is smaller than the average primary particle diameter of the second photocatalyst particles.

5 . The photocatalytic member according to claim 1 , wherein the average primary particle diameter of the conductive particles is 10 nm or more to 200 nm or less.

6 . The photocatalytic member according to claim 1 , wherein the content of the conductive particles is 5 wt % or more to 50 wt % or less based on the total content of the first photocatalyst particles, the second photocatalyst particles and the conductive particles.

7 . The photocatalytic member according to claim 1 , wherein the conductive particle comprises as a material a conductive metal oxide.

8 . The photocatalytic member according to claim 7 , wherein the conductive metal oxide comprises tin-doped indium oxide (ITO).

9 . The photocatalytic member according to claim 1 , wherein the conductive particle comprises as a material a metal.

10 . The photocatalytic member according to claim 9 , wherein the metal comprises gold.

11 . The photocatalytic member according to claim 1 , wherein the conductive particle comprises as a material a carbon material.

12 . The photocatalytic member according to claim 11 , wherein the carbon material comprises one or more selected from the group consisting of carbon black, Ketjen black, acetylene black, channel black, furnace black, thermal black, and lamp black.

13 . The photocatalytic member according to claim 2 , wherein the photocatalytic layer further comprises a covering portion that covers at least a part of the third region of the conductive particle.

14 . The photocatalytic member according to claim 13 , wherein the covering portion comprises one oxide selected from the group consisting of iron, silicon, zirconium, tantalum and cerium.

15 . The photocatalytic member according to claim 14 , wherein the covering portion comprises one or more selected from the group consisting of diiron trioxide and zirconium oxide.

16 . The photocatalytic member according to claim 13 , wherein the thickness of the covering portion is 0.5 nm or more to 50 nm or less.

17 . The photocatalytic member according to claim 1 further comprising an intermediate layer provided between the base and the photocatalytic layer.

18 . The photocatalytic member according to claim 1 , wherein a co-catalyst is supported on a surface of the first photocatalyst particle and/or the second photocatalyst particle.

19 . The photocatalytic member according to claim 18 , wherein the average primary particle diameter of the co-catalyst is less than 10 nm.

20 - 22 . (canceled)

23 . A method for producing a photocatalytic member according to claim 1 which comprises the base and the photocatalytic layer fixed thereon, the method comprising the steps of:
applying on the base a dispersion obtained by wetly dispersing into a solvent the first photocatalyst particles, the second photocatalyst particles, and the conductive particles which have Fermi level at a negative position relative to an electronic energy level at the upper end of the valence band of the first photocatalyst particle and at a positive position relative to an electronic energy level at the bottom end of the conduction band of the second photocatalyst particle, and are able to store an electron and a hole; and
drying the dispersion applied on the base.

24 . (canceled)

Assignees

• Toto Ltd
• Univ Tokyo
• Japan Tech Research Association Of Artificial Photosynthesis Chemical Process

Inventors

• Tokudome Hiromasa
• Okunaka Sayuri
• Domen Kazunari
• Hisatomi Takashi
• Wang Qian
• Jia Qingxin

Classifications

• B01J23/6525

  Molybdenum · CPC title

• B01J37/031

  Precipitation · CPC title

• B01J23/8472

  Vanadium · CPC title

• B01J23/63

  with rare earths or actinides · CPC title

• C01B3/042

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