Hydrogenation and Ammoniation of SrTiO3 for an Enhanced Visible-light Photocatalysis

Hydrogenation and ammoniation of SrTiO3 (STO), a normal ultraviolet photocatalyst, were performed by annealing STO〈100〉 in H2:N2=5%:95% and NH3, respectively, at various temperatures T. It was found that hydrogenation at T≥900 °C remarkably enhanced the UV photocatalytic ability of STO, but the visible-light photocatalysis was still unavailable, while ammoniation at T≥800 °C introduced the N doping, resulting in visible-light photocatalytic activity. Furthermore, when a hydrogenated STO was subjected to ammoniation, the visible-light photocatalytic ability was nearly the same as that of the ammoniated one; but the hydrogenation of an ammoniated one significantly enhanced visible-light photocatalysis, indicating a synergetic effect of hydrogenation and ammoniation. Discussions and identifications have been made to analyze these results.