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.

• Received 9 August 2010

DOI:https://doi.org/10.1103/PhysRevB.83.035202