Catalytic activity of zirconia on zirconium for the oxygen evolution reaction in potassium hydroxide

•The sample by arc plasma deposition higher activity than that by air oxidation.•The sample by arc plasma deposition has similar structure to that by air oxidation.•The sample by arc plasma deposition has highly dispersed than that by air oxidation. It has been reported that the Ni anode electrode used in alkaline water electrolysis (AWE) is degraded when the fluctuating electricity produced by renewable energy (wind and solar power) systems is used. To develop alternative materials, we focused on zirconium oxide because of its high chemical stability, and investigated its catalytic activity for the oxygen evolution reaction (OER) on zirconium oxides on a zirconium plate fabricated by both air oxidation (ZrO2/Zr) and arc-plasma deposition (ZrO2/Zr_APD). From cross-sectional observations and electrochemical results, the mixed tetragonal and monoclinic structure of ZrO2 was related to its catalytic activity for the OER. ZrO2/Zr_APD showed obviously a higher activity than ZrO2/Zr. The reason for this is that the particles are better dispersed in ZrO2/Zr_APD than in ZrO2/Zr, so the electrochemical surface area of ZrO2/Zr_APD seems to be larger than that of ZrO2/Zr.