The impact of benzene ring embedding on the performance of carbon nitride for photocatalytic hydrogen

Abstract

Forming local micro-π conjugate connection units in the structure of carbon nitride (CN) at the interface to capture photo-generated electrons can reduce the band gap and simultaneously facilitate the charge transfer. Herein, the H3BTC/CN composites with benzene ring embedded structure were prepared through the acid-base reaction between H3BTC and melamine. The precursor reaction method effectively enhanced the dispersity and utilization efficiency of modification molecule. The introduced benzene ring of H3BTC increased the double bonds of π conjugated system, decreased the band gap and widened the response range of visible light. At the same time, benzene ring acted as the electron acceptor to capture photo-generated electrons and promote the effective separation of photo-generated charge carriers. The optimal catalyst, 7.5 wt% H3BTC/CN showed an enhanced photocatalytic hydrogen evolution rate of 301 μmol g-1h−1, which was 21.8 times higher than that of pure CN. The work manifested the positive impact of benzene ring embedding on CN structure and photocatalytic performance, which proposed a new strategy for the design and preparation of high-efficiency photocatalyst.