The improvement of photocatalytic performance for hydrogen evolution over mesoporous g-C3N4 modified with nitrogen defects

Abstract

In this study, nitrogen defect (cyano-group and N vacancy)-modified mesoporous g-C₃N₄ (CNMCN) was synthesized via a new in situ silica gel strategy. Resultant CNMCN was analyzed via numerous techniques such as TEM, BET, XRD, FTIR, XPS, PL and DRS. The results revealed that the introduced mesoporous structure, cyano-group and N vacancy, could increase surface area, improve the separation of photoinduced charge and heighten light response capacity. These positive factors promoted CNMCN exhibiting better photocatalytic ability for splitting water, its H₂ evolution rate was around 14.7-fold more than that of bulk g-C₃N₄, and excellent continuous service capacity was also showed. Moreover, CNMCN had better performance than mesoporous g-C₃N₄, cyano-group modified g-C₃N₄ and N vacancy modified g-C₃N₄. Apparently, this present study provides a new thought for preparing mesoporous structure N defect-modified g-C₃N₄, which might be applied in clean energy production and environmental restoration.