Manganese-iridium composite oxide for water splitting catalyst, manganese-iridium composite oxide electrode material, and their production methods

Patent metadata

Field	Value
Publication number	US-2023175152-A1
Application number	US-202117912686-A
Country	US
Kind code	A1
Filing date	Mar 19, 2021
Priority date	Mar 25, 2020
Publication date	Jun 8, 2023
Grant date	—

Abstract

To provide a manganese-iridium composite oxide, a manganese-iridium composite oxide and a manganese-iridium composite oxide electrode material, having high catalytic activity produced at low cost, to be used as an anode catalyst for oxygen evolution in water electrolysis, and their production methods.A manganese-iridium composite oxide, which has an iridium metal content ratio (iridium/(manganese+indium)) of 0.1 atomic % or more and 30 atomic % or less, and has interplanar spacings of at least 0.243±0.002 nm, 0.214±0.002 nm, 0.165±0.002 nm, 0.140±0.002 nm, and a manganese-iridium composite oxide electrode material comprising an electrically conductive substrate constituted by fibers at least part of which are covered with the above manganese-iridium composite oxide.

First claim

1 . A manganese-iridium composite oxide, which has an iridium metal content ratio (iridium/(manganese+iridium)) of 0.1 atomic % or more and 30 atomic % or less, and has interplanar spacings of at least 0.243±0.002 nm, 0.214±0.002 nm, 0.165±0.002 nm and 0.140±0.002 nm.

2 . A manganese-iridium composite oxide electrode material comprising an electrically conductive substrate constituted by fibers at least part of which are covered with the manganese-iridium composite oxide as defined claim 1 .

3 . The manganese-iridium composite oxide electrode material according to claim 2 , wherein the amount of the covering manganese-iridium composite oxide is 0.1 mg/cm 2 or more and 25 mg/cm 2 or less per geometric area of the electrically conductive substrate.

4 . The manganese-iridium composite oxide electrode material according to claim 2 , wherein the electrically conductive substrate is constituted by carbon, titanium, or platinum-covered titanium.

5 . A laminate comprising the manganese-iridium composite oxide electrode material as defined in claim 2 , and a polymer electrolyte membrane.

6 . A method for producing an manganese-iridium composite oxide electrode material comprising an electrically conductive substrate constituted by fibers at least part of which are covered with the manganese-iridium composite oxide as defined in claim 1 , which comprises electrodepositing the manganese-iridium composite oxide on the fibers constituting the electrically conductive substrate by electrolysis of a mixed solution containing sulfuric acid/manganese sulfate/iridium salt.

7 . A method for producing an manganese-iridium composite oxide electrode material comprising an electrically conductive substrate constituted by fibers at least part of which are covered with the manganese-iridium composite oxide as defined in claim 1 , which comprises covering the fibers constituting the electrically conductive substrate with the manganese-iridium composite oxide by electrolysis with a sulfuric acid/manganese sulfate mixed solution and then by electrolysis with a mixed solution containing sulfuric acid/iridium salt.

8 . The method for producing the manganese-iridium composite oxide electrode material according to claim 6 , wherein a heat treatment is conducted.

9 . The method for producing the manganese-iridium composite oxide electrode material according to claim 8 , wherein the heat treatment is conducted at from 180° C. to 500° C. for from 30 minutes to 8 hours.

10 . The production method according to claim 6 , wherein the manganese-iridium composite oxide is electrodeposited in a deposition amount of from 0.1 mg/cm 2 or more and 25 mg/cm 2 or less per geometric area.

11 . An oxygen evolution electrode active material in water electrolysis, containing the manganese-iridium composite oxide as defined in claim 1 .

12 . An oxygen evolution electrode containing the oxygen evolution electrode active material as defined in claim 11 .

13 . A laminate comprising the oxygen evolution electrode as defined in claim 12 and a polymer electrolyte membrane.

14 . A water electrolysis apparatus, comprising the manganese-iridium composite oxide electrode material as defined in claim 2 .

15 . A method for producing hydrogen, which comprises conducting water electrolysis using the manganese-iridium composite oxide electrode material as defined in claim 2 .

Assignees

• Riken
• Tosoh Corp

Inventors

• Nakamura Ryuhei
• BONNET Nadege
• Kong Shuang
• Suetsugu Kazumasa

Classifications

• C25B11/065

  Carbon · CPC title

• C25B11/063

  Valve metal, e.g. titanium · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C25B11/075 Primary

  consisting of a single catalytic element or catalytic compound · CPC title

• C25B11/052

  Electrodes comprising one or more electrocatalytic coatings on a substrate · CPC title