Water oxidation catalyst having low overpotential for oxygen evolution reaction

• US 10,639,615 B2
• Filed: 10/05/2017
• Issued: 05/05/2020
• Est. Priority Date: 10/05/2016
• Status: Active Grant

• Current Assignee: Council of Scientific & Industrial Research
• Original Assignee: Council of Scientific & Industrial Research
• Inventors: Ramsundar, Rani Mohan, Joy, Pattayil Alias
• Primary Examiner(s): Soliman, Haytham
• Application Number:
  US16/339,753
• Publication Number:
  US 20200047162A1
• Time in Patent Office: 943 Days
• Field of Search: 502343
• CPC Class Codes: B01J 23/005 Spinels
• CPC Class Codes: B01J 23/80 with zinc, cadmium or mercury
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/33 Electric or magnetic properties
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/50 characterised by their shape or configuration
• CPC Class Codes: B01J 35/613 10-100 m2/g
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 37/036 to form a gel or a cogel
• CPC Class Codes: B01J 37/04 Mixing B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/088 Decomposition of a metal salt
• CPC Class Codes: C01B 2203/1047 Group VIII metal catalysts
• 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

Abstract

The present invention discloses a water oxidation catalyst having composition Zn_xCo_(3-x)O₄ for splitting water into oxygen and hydrogen gas and a process for the preparation thereof.

Claims

1. A process for the synthesis of a water oxidation catalyst having composition Zn_xCo_(3-x)O₄, for splitting water into oxygen and hydrogen gases, wherein x is selected from 0, 0.2, 0.4, 0.6, 0.8 and 1.0, the process comprising the steps of:

a) dissolving cobalt nitrate hexahydrate and zinc nitrate hexahydrate separately in solvent to afford solution of both;

b) adding said both solutions to the solution of glycine in solvent followed by stirring to obtain a uniform solution, wherein the ratio of cobalt plus zinc nitrate or metal nitrate;

glycine is in the range of 1;

0.3 to 1;

0.5; and

c) evaporating the solution of step (b) at temperature in the range of 180 to 220°

C. followed by burning the resulting thick mass to obtain a water oxidation catalyst.

2. The process as claimed in claim 1, wherein said solvent of step (a) is water.

3. The process as claimed in claim 1, wherein said water oxidation catalyst is Zn_0.8Co_2.2O₄.

4. The process as claimed in claim 1, wherein the ratio of cobalt plus zinc nitrate or metal nitrate:

glycine is in the range of 1;

0.3 to 1;

0.45.

5. The process as claimed in claim 1, wherein said water oxidation catalyst shows electrocatalytic activity with low overpotential in the range of 0.25 V to 0.27 V, at 10 mA cm⁻

2.

6. The process as claimed in claim 1, wherein said catalyst shows electrocatalytic activity with low overpotential of 0.254 V, at 10 mA cm⁻

2.

7. The process as claimed in claim 1, wherein said catalyst is comprised of spinel structure and spherical in shape with the size range of 7-10 nm.

8. The process as claimed in claim 1, wherein surface area of said water oxidation catalyst is in the range of 70-120 m²/g.

9. The process as claimed in claim 1, wherein said catalyst is used as oxygen evolution catalyst.