Construction of Ag SPR-promoted step-scheme porous g-C3N4/Ag3VO4 heterojunction for improving photocatalytic activity

In recent years, many effective photocatalysts have been developed in order to solve the problems of organic pollutants. In this work, two-dimensional (2D) porous graphitic carbon nitride/Ag3VO4 (Pg-C3N4/Ag3VO4) composites containing Ag nanoparticles (NPs) have been successfully synthesized by chemical deposition methods. And methylene blue (MB) was used as a model organic pollutants. The MB degradation efficiency of photocatalysts was tested under visible light, and it was found that 40% Pg-C3N4/Ag3VO4 exhibited the best photocatalytic performance. The MB degradation rate of 40% Pg-C3N4/Ag3VO4 is 99.3% within 8 min. The improvement of photocatalytic performance of Pg-C3N4/Ag3VO4 composites was due to the formation of step-scheme heterojunction between Ag3VO4 and Pg-C3N4. In addition, the porous structure of Pg-C3N4 and Ag surface plasmon resonance (SPR) effect accelerate the separation and transmission of electron-hole pairs, and reduce the probability of recombination. In addition, Ag SPR effect can enhance the absorption of visible light. Moreover, it is found that the superoxide ions (center dot O-2(-)) and holes (h(+)) play a major role in photocatalytic degradation through capture tests. Finally, the possible charge transfer mechanism is proposed.