Photocatalytic hydrogen production from water, and photolysis system for the same

Patent metadata

Field	Value
Publication number	US-2016271589-A1
Application number	US-201315029577-A
Country	US
Kind code	A1
Filing date	Oct 17, 2013
Priority date	Oct 17, 2013
Publication date	Sep 22, 2016
Grant date	—

Abstract

In an embodiment, a photocatalyst for the generation of diatomic hydrogen from a hydrogen containing precursor under the influence of actinic radiation comprises: a semiconductor support of SrTiO 3 and TiO 2 , wherein a molar ratio of SrTiO 3 and TiO 2 in the semiconductor support is at least 0.01; and a gold and palladium alloy on said semiconductor support. Included herein are embodiments of a photocatalyst system, methods of making diatomic hydrogen, and methods of making the photocatalyst.

First claim

We claim:

1 . A photocatalyst for the generation of diatomic hydrogen from a hydrogen containing precursor under the influence of actinic radiation comprising:
a semiconductor support of SrTiO 3 and TiO 2 , wherein a molar ratio of SrTiO 3 and TiO 2 in the semiconductor support is at least 0.01; and a gold and palladium alloy on said semiconductor support.

2 . The photocatalyst according to claim 1 , wherein the alloy is present on the semiconductor support as particles having an average major axis length of 1-100 nm.

3 . (canceled)

4 . The photocatalyst according to claim 1 , wherein the alloy comprises greater than or equal to 90 wt %, of palladium and gold, based on the weight of the alloy.

5 . The photocatalyst according to claim 1 , wherein greater than or equal to 90 wt %, of the gold and palladium in the alloy are present in their non-oxidized state.

6 . The photocatalyst according to claim 1 , wherein the alloy further comprises at least one of silver and copper.

7 . The photocatalyst according to claim 1 , wherein the molar ratio of SrTiO 3 and TiO 2 is selected such that the semiconductor support has one or more, bandgaps between 2.8 eV and 3.3 eV.

8 . (canceled)

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

10 . (canceled)

11 . The photocatalyst according to claim 1 , wherein at least part of the alloy is covered with a layer of the semiconductor support.

12 . The photocatalyst according to claim 1 , wherein at least part of the alloy is covered with a layer of the semiconductor support, and wherein the layer has a thickness of 1 to 5 nm.

13 . The photocatalyst according to claim 1 , wherein the semiconductor support is a mixture comprising SrTiO 3 and TiO 2 that is physically inseparable.

14 . A method for preparing a photocatalyst according to claim 1 comprising providing a semiconductor support and depositing gold and palladium so that a gold and palladium alloy is formed on the semiconductor support.

15 . 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.

16 . The method according to claim 15 , wherein the actinic radiation has a photonic energy of at least 2.5 eV and a radiant flux density of at least 0.1 mW/cm 2 .

17 . (canceled)

18 . The method of claim 15 , wherein the hydrogen containing precursor is a mixture of water and alcohol wherein the amount of alcohol is from 0.1 to 10% by volume, a mixture of water and diol wherein the amount of diol is from 0.1 to 10% by volume, or a mixture of water, alcohol, and diol wherein the combined amount of alcohol and diol is from 0.1 to 10% by volume based on the volume of the mixture.

19 . (canceled)

20 . The method of claim 15 , wherein the hydrogen containing precursor is a mixture of water and glycerol wherein the amount of glycerol is from 0.1 to 10% by volume, or a mixture of water, glycerol, and diol wherein the combined amount of glycerol and diol is from 0.1 to 10% by volume based on the volume of the mixture.

21 . The method according to claim 18 , wherein the mixture is an aqueous solution.

22 . (canceled)

23 . (canceled)

24 . A method for preparing a photocatalyst according to claim 1 , comprising:
i) combining a titanium precursor, and a strontium salt solution; ii) raising the pH to a value such that precipitation occurs; iii) washing the precipitate from step ii) with water; iv) calcining the precipitate at a temperature in the range of 500 to 800° C. so as to form the support; and v) depositing the gold and palladium onto the support.

25 . The method of claim 24 , wherein step i) further comprises lowering the pH of the mixture obtained by combining said titanium precursor and strontium salt solution to a value of at most 4.

26 . The method according to claim 24 , further comprising heating the support at a temperature of 300° C. to 800° C. in an inert or reducing atmosphere for a period from 1 to 24 hours so as to cover the alloy at least in part with a layer of semiconductor support having a thickness of 1 to 5 nm.

27 . (canceled)

28 . (canceled)

29 . The method according to claim 24 , wherein the titanium precursor comprises a titanium halogenide.

Assignees

• Saudi Basic Ind Corp

Inventors

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

Classifications

• Y02E60/36

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

• B01J35/77

  Compounds characterised by their crystallite size · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title