Photocatalytic Selective Anaerobic Oxidation of 5-Hydroxymethylfurfural via Zn0.5Cd0.5S/NaBiS2 S-Scheme Heterojunction

Abstract

Photocatalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) to the high-value-added chemical 2,5-diformylfuran (DFF) coupled with concurrent hydrogen production offers an efficient and sustainable strategy for simultaneously obtaining green energy and fine chemicals. In this study, a series of Zn_0.5Cd_0.5S/NaBiS₂ (ZCS/NBS) composites featuring S-type heterojunctions were successfully prepared via a one-step alkaline hydrothermal method, achieving efficient photocatalytic anaerobic oxidation of HMF to selectively produce DFF while co-producing H₂. HRTEM observation confirms the formation of a tightly integrated heterojunction between the ZCS and NBS. An interfacial electric field formed at the heterojunction of ZCS/NBS significantly enhances the migration and separation efficiency of photogenerated carriers. Under visible-light irradiation, the ZCS/NBS-7 composite exhibits superior photocatalytic performance, achieving an HMF conversion of 67.81% with a DFF selectivity of 95.69%. This HMF conversion is 5.4 times higher than that of pristine ZCS (12.46%), while the H₂ production rate reaches 81.11 µmol/g/h, which is 14.4 times greater than that of pristine ZCS (5.63 µmol/g/h). This study highlights the significant application potential of twinned ZCS in the photocatalytic selective anaerobic oxidation of HMF and offers valuable insights into the design of suitable heterojunction materials for photocatalytic organic conversion.