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

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+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, 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.