Photocatalyst and use thereof

• US 20060283701A1
• Filed: 06/07/2006
• Published: 12/21/2006
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company), Postech Foundation
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Postech Foundation
• Inventors: Li, Wei, Lee, Jae S., Oh, Se H., Jang, Jum S.
• Granted Patent: US 7,625,835 B2
• Time in Patent Office: Days
• US Class Current: 204/157.520
• CPC Class Codes: B01J 27/04 Sulfides
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: C01B 3/042 Decomposition of water
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y10S 428/93 Electric superconducting
• CPC Class Codes: Y10S 977/811 Of specified metal oxide composition, e.g. conducting or semiconducting compositions such as ITO, ZnOx
• CPC Class Codes: Y10S 977/812 Perovskites and superconducting composition, e.g. BaxSr1-xTiO3
• CPC Class Codes: Y10S 977/813 Of specified inorganic semiconductor composition, e.g. periodic table group IV-VI compositions
• CPC Class Codes: Y10T 428/2991 Coated

Abstract

A composite photocatalyst includes a semiconducting core and a nanoscale particle disposed on a surface of the semiconducting core, wherein the nanoscale particle is an electron carrier, and wherein the photocatalyst is sensitive to visible light irradiation.

Claims

1. A composite photocatalyst, comprising:

a semiconducting core; and

a nanoscale particle disposed on a surface of the semiconducting core, wherein the nanoscale particle is an electron carrier having a different composition than the semiconducting core, and wherein the composite photocatalyst is sensitive to visible light irradiation.

2. The composite photocatalyst of claim 1, wherein the semiconducting core comprises CdS, Si, Ge, GaP, GaAs, GaSb, InSb, InP, CdTe, InN, or a metal oxide.

3. The composite photocatalyst of claim 1, wherein the semiconducting core has an average smallest dimension of about 250 nanometers.

4. The composite photocatalyst of claim 1, wherein the nanoscale particle comprises TiO₂, NiO, Na₂TiO₃, ZnO, LaMnO₃, CuFeO₂, or a combination comprising at least one of the foregoing.

5. The composite photocatalyst of claim 1, wherein the nanoscale particle has an average longest dimension of about 50 nanometers.

6. The composite photocatalyst of claim 1, wherein a mole fraction of the nanoscale particle, based on a total number of moles of the semiconducting core and the nanoscale particle, is greater than or equal to about 0.10 and less than or equal to about 0.90.

7. The composite photocatalyst of claim 1, further comprising a co-catalyst, having a different composition than the semiconducting core and the nanoscale particle, disposed on the surface of the semiconducting core and/or a surface of the nanoscale particle.

8. The composite photocatalyst of claim 7, wherein the co-catalyst comprises Ni, Pt, Rh, Ag, Ru, Pd, IrO₂, an oxide of nickel, RuO₂, or a combination comprising at least one of the foregoing.

9. The composite photocatalyst of claim 7, wherein an amount of the co-catalyst in the composite photocatalyst is about 0.01 to about 10 weight percent, base on a total weight of the composite photocatalyst.

10. A composite photocatalyst, comprising:

a CdS core having an average smallest dimension of about 250 nanometers; and

a nanoscale particle of TiO₂ disposed on a surface of the CdS core, wherein the nanoscale particle of TiO₂, wherein the composite photocatalyst is sensitive to visible light irradiation.

11. The composite photocatalyst of claim 10, wherein a mole fraction of the nanoscale particle of TiO₂, based on a total number of moles of the CdS core and the nanoscale particle of TiO₂, is greater than or equal to about 0.33 and less than or equal to about 0.80.

12. The composite photocatalyst of claim 10, further comprising a co-catalyst disposed on the surface of the CdS core and/or a surface of the nanoscale particle of TiO₂.

13. The composite photocatalyst of claim 12, wherein the co-catalyst is Ni, Pt, Rh, Ag, Ru, Pd, IrO₂, an oxide of nickel, RuO₂, or a combination comprising at least one of the foregoing.

14. The composite photocatalyst of claim 12, wherein an amount of the co-catalyst in the composite photocatalyst is about 0.01 to about 10 weight percent, base on a total weight of the composite photocatalyst.

15. A method of using a composite photocatalyst, comprising:

irradiating a gas or liquid medium comprising the composite photocatalyst with light, wherein the composite photocatalyst comprises a semiconducting core and a nanoscale particle disposed on a surface of the semiconducting core, wherein the nanoscale particle is an electron carrier having a different composition than the semiconducting core.

16. The method of claim 15, wherein the light is visible light having a wavelength greater than or equal to about 400 nanometers.

17. The method of claim 15, wherein the composite photocatalyst comprises about 0.05 to about 10 grams per 25 square centimeters of an irradiated portion of the medium.

18. The method of claim 15, wherein the irradiating the gas or liquid medium comprising the composite photocatalyst with light is effective to produce hydrogen, remove a malodorous gas, decompose a harmful substance or to catalyze a photochemical reaction.

19. The method of claim 15, wherein the medium is water, and the irradiating the water comprising the composite photocatalyst with light is effective to produce hydrogen gas.

20. The method of claim 19, wherein the water further comprises a reducing agent, and the hydrogen gas production is anoxic.