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

Abstract

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/Ag 3 VO 4 (Pg-C 3 N 4 /Ag 3 VO 4 ) 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-C 3 N 4 /Ag 3 VO 4 exhibited the best photocatalytic performance. The MB degradation rate of 40%Pg-C 3 N 4 /Ag 3 VO 4 is 99.3% within 8 min. The improvement of photocatalytic performance of Pg-C 3 N 4 /Ag 3 VO 4 composites was due to the formation of step-scheme heterojunction between Ag 3 VO 4 and Pg-C 3 N 4 . In addition, the porous structure of Pg-C 3 N 4 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 ( O 2 − ) and holes (h + ) play a major role in photocatalytic degradation through capture tests. Finally, the possible charge transfer mechanism is proposed. • 2D/2D Pg-C 3 N 4 /Ag 3 VO 4 composite was successfully prepared. • The composite showed high visible light photocatalytic activity. • The composite showed excellent photostability. • Step-scheme photocatalytic mechanism is proposed.