Enhanced reactive oxygen species on a phosphate modified C3N4/graphene photocatalyst for pollutant degradation

Abstract

Carbon nitride whose surface is modified with phosphate is hybridized with graphene nanosheets by heating a mixture of melamine and graphene oxide, followed by stirred them in a phosphoric acid solution. The as-prepared phosphate–C₃N₄/graphene photocatalysts exhibited a higher photocatalytic performance for degrading Rh.B under visible light irradiation than C₃N₄, phosphate–C₃N₄ and current well-known C₃N₄/graphene photocatalysts. It can be ascribed to the enhancement of the production of OH radicals which is due to the simultaneous presence of phosphate and graphene species. The surface phosphation and grafted graphene sheet enhanced the formation of unbound OH radicals instead of surface-bound OH radicals on the phosphate modified C₃N₄ surface while the grafted graphene accelerates the electron separation from excited C₃N₄. Moreover, the photocatalytic activity of the phosphate–C₃N₄/graphene photocatalysts can be optimized by monitoring the content of graphene that is about 2 wt%.