Photocatalysts based on bismuth oxyhalide, process for their preparation and uses thereof

Patent metadata

Field	Value
Publication number	US-10717664-B2
Application number	US-201414910202-A
Country	US
Kind code	B2
Filing date	Aug 4, 2014
Priority date	Aug 5, 2013
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

The invention provides a process for the preparation of bismuth oxyhalide, comprising a precipitation of bismuth oxyhalide in an acidic aqueous medium in the presence of a reducing agent. Also provided are bismuth oxyhalide compounds doped with elemental bismuth Bi (0) . The use of Bi (0) doped bismuth oxyhalide as photocatalysts in water purification is also described.

First claim

The invention claimed is:

1. A process for the preparation of bismuth oxyhalide, comprising combining at least one bismuth salt and at least one halide source in an acidic aqueous medium in the presence of a reducing agent, and isolating a precipitate formed, wherein the so-formed bismuth oxyhalide is doped with elemental bismuth Bi (0) , wherein the so-formed bismuth oxyhalide is doped with elemental bismuth Bi (0) at a doping level of not more than 7 molar %, relative to the total amount of the bismuth.

2. A process according to claim 1 , wherein the halide source is an organic halide salt.

3. A process according to claim 2 , wherein the organic halide salt is selected from the group consisting of quaternary ammonium salts represented by the formulas N + R 1 R 2 R 3 R 4 C − , N + R 1 R 2 R 3 R 4 Br − and their mixture, wherein R 1 , R 2 , R 3 and R 4 are alkyl groups, which may be the same or different.

4. A process according to claim 1 , wherein the reducing agent comprises hydride.

5. A process according to claim 4 , wherein the reducing agent is borohydride.

6. A process according to claim 1 , wherein the acidic aqueous medium comprises an organic acid.

7. A process according to claim 1 , wherein the bismuth oxyhalide is selected from the group consisting of BiOCl, BiOBr and BiOCl y Br 1-y wherein y is in the range from 0.5 to 0.95.

8. A process according to claim 7 , wherein the bismuth oxyhalide is BiOCl y Br 1-y wherein y is in the range from 0.6 to 0.95.

9. A process according to claim 1 , wherein the bismuth oxyhalide is selected from the group consisting of:
Bi (0) doped-BiOCl;
Bi (0) doped-BiOBr; and
Bi (0) doped-BiOCl y Br 1-y wherein y is in the range from 0.5 to 0.95.

10. A process according to claim 1 , wherein the doping level of Bi(0) is from 0.1 to 3 molar %.

11. A process for the preparation of bismuth oxyhalide, comprising combining at least one bismuth salt and at least one halide source in an acidic aqueous medium in the presence of a reducing agent, and isolating a precipitate formed, wherein the so-formed bismuth oxyhalide is doped with elemental bismuth Bi (0) , wherein the halide source is an organic halide salt.

12. A process for the preparation of bismuth oxyhalide, comprising combining at least one bismuth salt and at least one halide source in an acidic aqueous medium in the presence of a reducing agent, and isolating a precipitate formed, wherein the so-formed bismuth oxyhalide is doped with elemental bismuth Bi (0) , wherein the reducing agent comprises hydride.

Assignees

• Yissum Res Dev Co Of Hebrew Univ Jerusalem Ltd

Inventors

• Sasson Yoel
• Gnayem Hani

Classifications

• B01J2235/00

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

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J2235/15

  X-ray diffraction · CPC title

• B01J35/70

  characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00) · CPC title

• B01J37/0221

  of particles · CPC title