Photocatalyst, method for preparation, photolysis system

Patent metadata

Field	Value
Publication number	US-9339792-B2
Application number	US-201314395010-A
Country	US
Kind code	B2
Filing date	Apr 22, 2013
Priority date	Apr 26, 2012
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

The present invention relates to a photocatalyst for the generation of diatomic hydrogen from a hydrogen containing precursor under the influence of actinic radiation comprising semiconductor support particles comprised of SrTiO 3 and TiO 2 with one or more noble and/or transition metals deposited thereon. Further disclosed is a method for preparing such catalyst and a method for generating diatomic hydrogen by photolysis.

First claim

The invention claimed is:

1. A photocatalyst for the generation of diatomic hydrogen from a hydrogen containing precursor under the influence of actinic radiation comprising: semiconductor support particles comprising SrTiO 3 and TiO 2 , and which semiconductor support particles have a noble and/or transition metal deposited thereon and wherein a molar ratio of SrTiO 3 and TiO 2 in the semiconductor support particles is at least 0.01, and wherein the photocatalyst is not doped with nitrogen.

2. The photocatalyst according to claim 1 wherein the ratio is in the range of from 0.05 to 1.

3. The photocatalyst according to claim 1 , wherein the noble and/or transition metals is deposited in the form of metal particles wherein an average major axis direction length of said metal particles is at most 5 nm.

4. The photocatalyst according to claim 1 , wherein the molar ratio is selected such that the semiconductor support has a bandgap between 2.8 eV and 3.3 eV.

5. The photocatalyst according to claim 1 , wherein the noble and/or transition metal is selected such that it has a Plasmon loss in the range from 500 nm to 600 nm as determined by UV-Vis reflectance absorption.

6. The photocatalyst according to claim 1 , wherein the noble and/or transition metal comprises at least one of platinum, rhodium, gold, ruthenium, palladium and rhenium.

7. The photocatalyst according to claim 1 , wherein at least 75 wt % of the noble and/or transition metals is in its non-oxidised state.

8. The photocatalyst according to claim 1 , wherein the noble and/or transition metal is present in an amount in the range from 0.1 to 10 wt % based on the combined weight of the semiconductor support particles and the noble and/or transition metals deposited thereon and based on the noble and/or transition metals in their elemental state.

9. The photocatalyst according to claim 1 , wherein the catalyst has a BET surface area of from 30 to 60 m 2 per gram catalyst using the nitrogen absorption technique.

10. A method for preparing a photocatalyst according to claim 1 , comprising:
combining a titanium precursor and a strontium salt solution to form a mixture having a pH;
raising the pH to a value such that precipitation occurs, forming a precipitate;
washing the precipitate with water;
calcining the precipitate at a temperature in the range of from 500 to 800° C. so as to form the support; and
depositing the noble and/or transition metal onto the support.

11. The method of claim 10 wherein the combining step further comprises lowering the pH of the mixture to a value of at most 4.

12. A method for generating diatomic hydrogen from a hydrogen containing precursor, comprising contacting a photocatalyst according to claim 1 with the hydrogen containing precursor while exposing the photocatalyst to actinic radiation to forming the diatomic hydrogen.

13. Photolysis system for the generation of diatomic hydrogen comprising:
a reaction zone containing a photocatalyst according to claim 1 , with the method comprising
combining a titanium precursor and a strontium salt solution to form a mixture having a pH;
lowering the pH of the mixture to a value of at most 4;
raising pH to a value such that precipitation occurs, forming a precipitate;
washing the precipitate with water;
calcining the precipitate at a temperature in the range of from 500 to 800° C. so as to form the support; and
depositing the noble and/or transition metal onto the support.

14. A semiconductor material comprising SrTiO 3 and TiO 2 wherein a molar ratio of SrTiO 3 and TiO 2 is at least 0.01, said semiconductor material being obtainable by a method comprising:
combining a titanium precursor and a strontium salt solution to form a mixture having a pH,
raising the pH to a value such that precipitation occurs forming a precipitate;
washing the precipitate with water; and
calcining the precipitate at a temperature in the range of from 500 to 800° C. so as to form the semiconductor material; and
wherein the semiconductor material is not doped with nitrogen.

15. The photocatalyst according to claim 4 , wherein the molar ratio is selected such that the semiconductor support has two bandgaps between 2.8 eV and 3.3 eV.

16. The method of claim 10 wherein titanium precursor comprises a titanium halogenide.

17. The photocatalyst of claim 1 , wherein the photocatalyst does not contain nitrogen.

18. The photocatalyst of claim 5 , wherein the noble and/or transition metal comprises at least one of rhodium, gold, ruthenium, palladium, and rhenium.

19. The photocatalyst of claim 18 , wherein the noble and/or transition metal comprises gold.

20. A photocatalyst for the generation of diatomic hydrogen from a hydrogen containing precursor under the influence of actinic radiation comprising: semiconductor support particles comprising SrTiO 3 and TiO 2 , and which semiconductor support particles have a noble and/or transition metal deposited thereon and wherein a molar ratio of SrTiO 3 and TiO 2 in the semiconductor support particles is at least 0.01, wherein the TiO 2 comprises rutile TiO 2 .

Assignees

• Saudi Basic Ind Corp

Inventors

• Idriss Hicham
• Khaja Ahmed Wahab
• Odedairo Taiwo
• Mussa Majed Mohammed

Classifications

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title

• C01B3/26

  using catalysts · CPC title

• B01J37/031

  Precipitation · CPC title

• C01B3/042

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

• Y02E60/364

  Cross-Sectional Technologies · mapped topic