Electrochemical activity of a blue anatase TiO2 nanotube array for the oxygen evolution reaction in alkaline water electrolysis

Abstract

An anatase TiO2 nanotube array (NTA) was fabricated by anodization and successive heat treatments. When the anatase TiO2 NTA was cathodically polarized, its color changed to blue, and it could be used as an electrochemically active anode for an oxygen evolution reaction (OER) in alkaline water electrolysis. The structure of the blue anatase TiO2 NTA was controlled by the anodization conditions and its catalytic activity increased with an increase of the surface area. The activity of the blue anatase TiO2 NTA gradually reduced with the continued OER because of the partial oxidation of Ti3+ to Ti4+. However, an intermittent cathodic regeneration process could significantly slow its reduction rate. The blue anatase TiO2 NTA could be an alternative anode for alkaline water electrolysis.