Silver Phosphate/Graphitic Carbon Nitride as an Efficient Photocatalytic Tandem System for Oxygen Evolution

Abstract

Herein, we show the facile synthesis of an efficient silver phosphate/graphitic carbon nitride (Ag 3 PO 4/g‐C 3 N 4) photocatalyst for oxygen production and pollutant degradation by using electrostatically driven assembly and ion‐exchange processes. The composite materials demonstrate a sheet‐like C 3 N 4 structure, decorated with different Ag 3 PO 4 particles sizes. Detailed analysis of the reactions mechanism by electron‐spin resonance and radical‐capture agents strongly imply the formation of an in situ Z‐scheme by the evolution of small silver nanoparticles in the interface of the materials under illumination. The Ag nanoparticles improve charge separation within the composite material by acting as a storage and recombination center for electrons and holes from Ag 3 PO 4 and C 3 N 4, respectively. In addition, the photostability of Ag 3 PO 4 is enhanced relative to that of the bulk materials, which results in a stabilized heterojunction. We believe that this work provides new insight into the operation mechanism of composite photocatalysts for water splitting and opens the possibility for advanced photocatalysis based on the higher oxidation power of Ag 3 PO 4.