Homodispersed B-CN/P-CN S-scheme homojunction for enhanced visible-light-driven hydrogen evolution

Proper interface and band alignment always play essential roles in the separation of photoexcited charge of photocatalysts. In this work, we prepared a homodispersed S-scheme carbon nitride homojunction with local electron structure difference by a facile pre-doping and two-step calcination approach. Boron doping into heptazine created extra acceptor impurity, and phosphorus doping into heptazine created extra donor impurity, which eventually modulated the electronic structure of carbon nitride. As heptazines with different element doping were integrated into carbon nitride by recalcination, B-CN and P-CN formed a homodispersed homojunction and thus produced a rich interface. Meanwhile, caused by Fermi energy levels equilibrium, the band bending constructed an S-scheme homojunction, which stimulated photogenerated electrons to transfer from CB of B-CN to VB of P-CN. The homodispersed S-scheme homojunction structure led to efficient suppression of recombination of photoinduced charge and retained stronger redox charge. Consequently, the photocatalytic performance was dramatically boosted to 2620 mmol g(-1) from 60 mmol g(-1 )of pure CN in 4-h hydrogen evolution from water. This novel method for electron structure engineering helped to provide a new strategy for designing homojunction photocatalysts with excellent photocatalytic performance. (C) 2021 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communi-cations Co., Ltd.

Automated summary

In this study, a homodispersed S-scheme carbon nitride homojunction with enhanced photocatalytic performance was prepared through pre-doping and recalcination methods. The electron structure engineering and S-scheme homojunction construction facilitated efficient charge separation and redox reactions, resulting in significantly improved photocatalytic performance.