Origin of Photocatalytic Activation of Silver Orthophosphate from First-Principles

Abstract

First-principles density functional theory incorporating the LDA + U formalism has been used to investigate the origin of photocatalytic activation of Ag 3 PO 4 . The approach provides an improved band gap and the position of the valence band if both U p and U d are used. Through examining the energy band structure and density of states, we can understand why Ag 3 PO 4 is a promising photocatalyst for oxidizing water as well as degrading organic contaminants. The results show that Ag 3 PO 4 has a large dispersion of conduction band and the inductive effect of PO 4 3−, which help the separation of electron−hole pairs. It is demonstrated theoretically that Ag vacancies in Ag 3 PO 4 with high concentration have a significant effect on the separation of electron−hole pairs and optical absorbance in the visible-light region. These findings present a reasonable explanation of recent experimental results.