First-principles Calculation on Pt- and Au-modified Anatase TiO2(101) Surface

Structure stability and electronic structures of anatase TiO2(101) surface modified by noble metal Pt and Au have been investigated using plane-wave ultrasoft pseudopotentials. The results show that the adsorption inter- action is weak between noble atoms and anatase TiO2(101) surface, resulting in a slight effect on its electronic structure. However, under O-rich condition, it is found that Pt and Au atoms are favor of the Ti vacancies. Contrary to Au atom, Pt atom tends to diffuse from surface into bulk. Under Ti-rich condition, Pt and Au atoms are favor of the O vacancies. The calculated electronic structures of possible vacancy defects indicate that the appearance of surface vacancies not only avails to wet anatase TiO2(101) surfaces, but also enables their atoms to appear 5d impu- rity energy levels in band gap.