Photocatalyst composite particles and method for producing same

Patent metadata

Field	Value
Publication number	US-2017326531-A1
Application number	US-201515522148-A
Country	US
Kind code	A1
Filing date	Sep 30, 2015
Priority date	Oct 28, 2014
Publication date	Nov 16, 2017
Grant date	—

Abstract

Disclosed are metal nitride photoctalyst particles and/or metal oxynitride photocatalyst particles having high dispersibility. The metal nitride photoctalyst particles and/or metal oxynitride photocatalyst particles having high dispersibility can be obtained by containing metal nitride photoctalyst particles and/or metal oxynitride photocatalyst particles, which are capable of splitting water under visible light irradiation, and a phosphoric acid polymer that is adsorbed on the surface of the particles. Further, because these particles have high photocatalytic activity under visible light irradiation, splitting water by using these particles can generate hydrogen and/or oxygen with high efficiency.

First claim

1 . Photocatalyst composite particles comprising:
metal nitride photocatalyst particles and/or metal oxynitride photocatalyst particles, which are capable of splitting water under visible light irradiation, and a phosphoric acid polymer which is adsorbed on the surface of the particles.

2 . The photocatalyst composite particles according to claim 1 , wherein a ratio of A surface /A bulk is 0.8 or more to 1.2 or less, where A surface is an atomic concentration ratio on the surface of the photocatalyst composite particles, and is represented by (nitrogen atom concentration)/(nitrogen atom concentration+oxygen atom concentration), and A bulk is an atomic concentration ratio inside the photocatalyst composite particles, and is represented by (nitrogen atom concentration)/(nitrogen atom concentration+oxygen atom concentration).

3 . The photocatalyst composite particles according to claim 1 , wherein a surface zeta potential of a dispersion of the photocatalyst composite particles in pure water with the concentration of the photocatalyst composite particles being 1% by mass, is −30 mV or less.

4 . The photocatalyst composite particles according to claim 1 , wherein a weight ratio of the metal nitride photocatalyst particles and/or metal oxynitride photocatalyst particles to the phosphoric acid polymer is 1:0.005 or more to 1:0.3 or less.

5 . The photocatalyst composite particles according to claim 1 , wherein the photocatalyst composite particles support a co-catalyst.

6 . The photocatalyst composite particles according to claim 1 , wherein the photocatalyst composite particles are used for splitting water with visible light.

7 . A method for splitting water, wherein the photocatalyst composite particles according to claim 1 being in contact with water are irradiated with visible light.

8 . A dispersion comprising:
the photocatalyst composite particles according to claim 1 and a solvent capable of dispersing the photocatalyst composite particles.

9 . A photocatalytic member comprising:
a substrate and the photocatalyst composite particles according to claim 1 being fixed on the surface of the substrate.

10 . The photocatalytic member according to claim 9 , wherein the photocatalyst composite particles are fixed on the surface of the substrate by phosphate groups contained in the phosphoric acid polymer.

11 . The photocatalytic member according to claim 9 , wherein the photocatalyst composite particles are fixed on the surface of the substrate by ionic bonds or ester bonds through the phosphate groups.

12 . The photocatalytic member according to claim 9 , wherein the photocatalytic member is used for splitting water with visible light.

13 . A photocatalytic module for splitting water comprising the photocatalytic member according to claim 9 .

14 . A hydrogen producing system comprising the photocatalytic module for splitting water according to claim 13 .

15 . A method for producing the photocatalyst composite particles according to claim 1 , comprising mixing metal nitride photocatalyst particles and/or metal oxynitride photocatalyst particles, a phosphoric acid polymer, and a solvent without using dispersion media.

16 . The method for producing the photocatalyst composite particles according to claim 15 , wherein the method of mixing is stirring.

17 . The method for producing the photocatalytic member according to claim 9 , comprising applying a dispersion comprising the photocatalyst composite particles and a solvent capable of dispersing the photocatalyst composite particles to the surface of the substrate.

Assignees

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

Inventors

• Tokudome Hiromasa
• Okunaka Sayuri

Classifications

• C01B3/04

  by decomposition of inorganic compounds (reversible storage of hydrogen C01B3/0018) · CPC title

• B01J37/088

  Decomposition of a metal salt · CPC title

• B01J37/031

  Precipitation · CPC title

• B01D53/885

  Devices in general for catalytic purification of waste gases · CPC title

• B01J27/24

  Nitrogen compounds · CPC title