Plasmonic ternary hybrid photocatalyst based on polymeric g-C₃N₄ towards visible light hydrogen generation

Surface plasmon resonance (SPR) effect of noble metal nanoparticles (NPs) for photocatalysis has a significant enhancement. In this system, a plasmonic ternary hybrid photocatalyst of Ag/AgBr/g-C₃N₄ was synthetized and used in water splitting to generation H₂ under visible light irradiation. 18%Ag/AgBr/g-C₃N₄ showed the highest photoactivity, with the efficiency of hydrogen generation as high as 27-fold to that of pristine g-C₃N₄. Compared to simple mixture of Ag/AgBr and g-C₃N₄, hetero-composite Ag/AgBr/g-C₃N₄ showed a higher photoactivity, even though they contained same content of Ag/AgBr. We find that significant factors for enhancing properties were the synergistic effect between Ag/AgBr and g-C₃N₄, and the light absorption enhancing by SPR effect of Ag NPs. Ag/AgBr NPs firmly anchored on the surface of g-C₃N₄ and their high dispersion were also responsible for the improved activity and long-term recycling ability. The structure of Ag/AgBr/g-C₃N₄ hybrid materials and their enhancement to photocatalytic activity were discussed. Meanwhile, the possible reaction mechanism of this system was proposed.