Multivalence semiconductor photocatalytic materials

Patent metadata

Field	Value
Publication number	US-10213780-B2
Application number	US-201515510621-A
Country	US
Kind code	B2
Filing date	Sep 11, 2015
Priority date	Sep 12, 2014
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

Described herein are heterogeneous materials comprising a p-type semiconductor comprising two metal oxide compounds of the same metal in two different oxidation states and an n-type semiconductor having a deeper valence band than the p-type semiconductor valence bands, wherein the semiconductor types are in ionic communication with each other. The heterogeneous materials enhance photocatalytic activity.

First claim

What is claimed is:

1. A heterogeneous material comprising:
a p-type semiconductor comprising a first metal oxide compound and a second metal oxide compound, wherein the first metal oxide compound and the second metal oxide compound have different oxidation states of the same metal, and wherein the p-type semiconductor has a p-type valence band;
a first n-type semiconductor having an n-type valence band which is deeper than the p-type valence band, wherein the first n-type semiconductor is in ionic charge communication with the p-type semiconductor, and wherein the n-type semiconductor comprises 90 to 99.999 wt % of the heterogeneous material.

2. The heterogeneous material of claim 1 , further comprising a second n-type semiconductor.

3. The heterogeneous material of claim 1 , wherein the first n-type semiconductor is TiO 2 .

4. The heterogeneous material of claim 1 , wherein the first n-type semiconductor is a combination of anatase TiO 2 and rutile TiO 2 .

5. The heterogeneous material of claim 1 , wherein the first n-type semiconductor comprises WO 3 .

6. The heterogeneous material of claim 2 , wherein the molar ratio of the first n-type semiconductor to the second n-type semiconductor is about 0.5 to about 10.

7. The heterogeneous material of claim 2 , wherein the second n-type semiconductor is CeO 2 , GeO 2 , SnO 2 , or ZrO 2 .

8. The heterogeneous material of claim 2 , wherein the second n-type semiconductor is CeO 2 .

9. The heterogeneous material of claim 2 , wherein the second n-type semiconductor is GeO 2 .

10. The heterogeneous material of claim 2 , wherein the second n-type semiconductor is SnO 2 .

11. The heterogeneous material of claim 1 , wherein the p-type semiconductor comprises Cu x O.

12. The heterogeneous material of claim 1 , wherein the p-type semiconductor is about 0.001% to about 5% of the heterogeneous material by weight.

13. The heterogeneous material of claim 1 , wherein the p-type semiconductor is Cu x O, and is about 0.01% to about 1% of the heterogeneous material by weight.

14. A heterogeneous material comprising:
a p-type semiconductor comprising a first metal oxide compound and a second metal oxide compound, wherein the first metal oxide compound and the second metal oxide compound have different oxidation states of the same metal, and wherein the p-type semiconductor has a p-type valence band;
a first n-type semiconductor having an n-type valence band which is deeper than the p-type valence band, wherein the first n-type semiconductor is in ionic charge communication with the p-type semiconductor;
a second n-type semiconductor;
wherein at least 50% of the p-type semiconductor is loaded onto the surface of particles of the first n-type semiconductor and particles of the second n-type semiconductor.

15. A heterogeneous material comprising:
a p-type semiconductor comprising a first metal oxide compound and a second metal oxide compound, wherein the first metal oxide compound and the second metal oxide compound have different oxidation states of the same metal, and wherein the p-type semiconductor has a p-type valence band;
a first n-type semiconductor having an n-type valence band which is deeper than the p-type valence band, wherein the first n-type semiconductor is in ionic charge communication with the p-type semiconductor;
wherein the heterogeneous material is in the form of a powder.

16. A method of preparing a heterogeneous material comprising:
heating a mixture of:
1) a first n-type semiconductor and a second n-type semiconductor; and
2) an aqueous solution comprising a copper ion complex;
wherein the first n-type semiconductor and the second n-type semiconductor are mixed prior to combining the first n-type semiconductor and the second n-type semiconductor with the aqueous solution comprising the copper ion complex as a precursor of a p-type semiconductor;
wherein the copper ion complex comprises copper ions have at least two different oxidation states, and wherein the complex has a p-type valence band;
wherein the first and second n-type semiconductors have an n-type valence band which is deeper than the p-type valence band; and
wherein the copper ion complex comprises 0.001 to 10 wt % of the heterogeneous material.

17. The method of claim 16 , further comprising filtering the heterogeneous material out of the mixture of the after the mixture has been heated.

18. A method of decomposing a chemical compound, comprising exposing the chemical compound to a photocatalyst comprising the heterogeneous material of claim 1 in the presence of light.

19. The method of claim 18 , wherein the chemical compound is a pollutant.

20. A method of killing a microbe, comprising exposing the microbe to a photocatalyst comprising the heterogeneous material of claim 1 in the presence of light.

Assignees

• Nitto Denko Corp

Inventors

• Sambandan Ekambaram
• Zhang Bin

Classifications

• C02F1/32

  with ultraviolet light · CPC title

• B01J37/086

  Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid · CPC title

• B01D2255/802

  Photocatalytic · CPC title

• B01J21/063

  Titanium; Oxides or hydroxides thereof · CPC title

• B01J23/75

  Cobalt · CPC title