Nitrogen-deficient C3N4 coupled with AgBr construction Z-scheme heterojunction form double electric field to promote photogenerated carrier separation enhancement hydrogen evolution

Abstract

g-C₃N₄ is an excellent and affordable photocatalyst, but its weak built-in electric field slows down its photogenerated carrier separation rate. Meanwhile, modulating the interfacial electric field is also an effective way to increase the light-generated carrier separation efficiency. In this study, the built-in electric field of g-C₃N₄ is enhanced by using N vacancies (from 0.742 V to 0.868 V). Subsequently, the modified Nv-C₃N₄ (N₀CN) is utilized to create a heterojunction with AgBr to generate a synergistic effect of built-in and interfacial electric fields (from 0.868 V to 1.032 V). The photogenerated carrier separation was significantly enhanced by the synergistic interaction of the dual electric fields, leading to a notable improvement in the photocatalytic efficiency of A-N₀CN. The H₂ production performance reached 1884.6 µmolg^-1h⁻¹, which was measured 1047 times higher than that of N₀CN (1.8 µmolg^-1h⁻¹), A-CN (969.9 µmolg^-1h⁻¹) and CN (1.1 µmolg^-1h⁻¹), representing increases of 1.94 and 1713 times, respectively. This research offers a new perspective for catalyst design involving dual electric field synergy.