An internal electric field and interfacial S–C bonds jointly accelerate S-scheme charge transfer achieving efficient sunlight-driven photocatalysis

Abstract

Inadequate accessible active sites and inhibited electron separation efficiency are always burning issues. This work successfully solves the above problems by constructing a novel S-scheme heterojunction with S–C bonds bridging composed of hierarchical g-C₃N₄ (3DA-CN) coupled with sulfur vacancies (Sv) ZnIn₂S₄ (Sv-ZIS/CN). The special structure provides more active sites for the photocatalytic reaction and maintains multiple light transmission channels, resulting in the improvement of the capture and conversion of solar energy. The interfacial electric field and S–C bonds as well as their effects benefiting the regulation of the efficiency of electrons transfer for efficient photocatalytic reactions are deeply investigated and comprehended. The tetracycline degradation efficiency of Sv-ZIS/CN reaches 96.36% and has the highest k value (0.03361 min⁻¹), which is 7.55, 5.47 and 3.04 times that of 3DA-CN, Sv-ZIS and ZIS-S/CN (prepared by a mechanical approach), respectively. Meanwhile, H₂O₂ production experiments also verified that the photocatalytic activity of Sv-ZIS/CN was significantly improved compared with ZIS-S/CN. The mechanisms of tetracycline degradation and H₂O₂ production are discussed in depth. This work provides an unparalleled and impressive strategy to construct significantly efficient photocatalysts.