Chemically resistant, oxidic electrocatalyst for oxygen evolution during alkaline water electrolysis

Abstract

Disclosed is a biphasic electrically conductive perovskite-based mixed oxide of the structure ABOwith A=Ba, and B=Co, comprising additionally 5-45 at %, preferably 15 to 30 at %, particularly preferably 25 at % CoO(at % Co based on the total number of Co atoms in the perovskite ABOand 0.5 to 0.3 at %, preferably 1 to 2.5 at %, particularly preferably 2 at % (wherein the at % are referred to the total number of B cations in the perovskite ABO) Ti as dopant. Preferably, the mixed oxide has the stoichiometric formula BaCoTiO:CoOwith x=0.005 to 0.03, preferably x=0.01 to 0.025, particularly preferably x=0.02, wherein δ defines the vacancies in the perovskite structure and is in the range of about 0.1 to 0.8, preferably 0.3 to 0.7, particularly preferably about 0.5 to 0.6. Further disclosed are a catalyst and an anode comprising the mixed oxide, the use of the catalyst in alkaline water electrolysis or in metal-air batteries, the use of the mixed oxide for the preparation of an anode for alkaline water electrolysis or metal-air batteries. Further, manufacturing processes for a precursor solution for the mixed oxide and for the inventive anode are disclosed, as well as an amorphous mixed oxide having a Co:Ba ratio of about 2:1 and a TTB (Tetragonal Tungsten-Bronze)-like near structure obtainable by using the mixed oxide according to the invention as catalyst in the oxygen evolution reaction of alkaline water electrolysis, whereby said amorphous product is formed by leaching out Ba.