Theoretical study of high photocatalytic performance of Ag3PO4

The recent discovery of an excellent photocatalyst, Ag${}_{3}$PO${}_{4}$, motivated us to clarify the origin of its high performance. Our comprehensive study using density-functional-theory-based calculations has revealed that the formation of PO${}_{4}$ tetrahedral units with strong P-O bonds weakens the covalent nature of Ag-O bonds, inhibiting hybridization of Ag $d$ and O $p$. This excludes the $d$ character from the conduction-band minimum (CBM), leaving highly dispersive Ag $s$-Ag $s$ hybrid bands. The delocalized charge distribution of the CBM results in a small effective mass of the electron, which is advantageous for the carrier transfer to surface.