Effect of Semiconducting Properties of Oxide-Based Compounds on Oxygen Reduction Activity in Acidic Media

Effect of semiconducting properties of group 4 and 5 oxide-based films on catalytic activity of oxygen reduction reaction (ORR) has been investigated. In case of n-type semiconductor oxide catalysts, there are two reasons that the ORR activities are apparently observed to be low; there are two reasons; one is there are few active site with high quality and quantity on the surface, another is that although the relative active sites are exists on the surface the Schottky barrier suppresses the electron transfer from bulk to the surface. The positive correlation between flat-band potential and onset potential for the ORR of thick oxide films composed of titanium-niobium, -tantalum, and -zirconium oxides was observed, indicating that the ORR activities were governed by the semiconducting properties of the films.