Preparation of Structure Vacancy Defect Modified Diatomic‐Layered g‐C3N4 Nanosheet with Enhanced Photocatalytic Performance

Abstract Structure self‐modification of graphitic carbon nitride (g‐C3N4) without the assistance of other species has attracted considerable attention. In this study, the structure vacancy defect modified diatomic‐layered g‐C3N4 nanosheet (VCN) is synthesized by thermal treatment of bulk g‐C3N4 in a quartz tube with vacuum atmosphere that will generate a pressure‐thermal dual driving force to boost the exfoliation and formation of structure vacancy for g‐C3N4. The as‐prepared VCN possesses a large specific surface area with a rich pore structure to provide more active centers for catalytic reactions. Furthermore, the as‐formed special defect level in VCN sample can generate a higher exciton density at photoexcitation stage. Meanwhile, the photogenerated charges will rapidly transfer to VCN surface due to the greatly shortened transfer path resulting from the ultrathin structure (≈1.5 nm), which corresponds to two graphite carbon nitride atomic layers. In addition, the defect level alleviates the drawback of enlarged bandgap caused by the quantum size effect of nano‐scaled g‐C3N4, resulting in a well visible‐light utilization. As a result, the VCN sample exhibits an excellent photocatalytic performance both in hydrogen production and photodegradation of typical antibiotics.