Oxygen Adsorption on Anatase TiO₂ (101) and (001) Surfaces from First Principles

Abstract

The structural, adsorptive, and electronic properties of oxygen adsorption on anatase TiO₂ are investigated by first-principles calculations with special focus on two experimentally confirmed surfaces. We find that compared with (101) surface, the (001) surface exhibits lower oxygen adsorption energy, reduced band gap, and larger charge transfer, thereby holding the potential for the improvement of sensitivity to reductive gases. Moreover, the (001) surface is found to be more active in oxygen adsorption. These findings render a careful synthesis of anatase TiO₂ crystals so as to form, to the largest extent, the (001) surface primarily important for further improving gas-sensing properties of TiO₂-based sensors.