Tailoring Redox Active Sites with Dual-Interfacial Electric Fields for Concurrent Photocatalytic Biomass Valorization and H2 Production

Abstract

Light-driven photocatalytic conversion of biomass-derived substrates into value-added chemicals, coupled with hydrogen (H2) evolution, offers a promising route for solar energy utilization and sustainable chemical production. However, achieving high efficiency and selectivity in such dual-functional systems remains a challenge. Herein, the rational construction of a hierarchical Au/Zn3In2S6/Co3O4 (Au/ZIS/Co3O4) photocatalyst is reported for selective dehydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), coupled with H2 generation. The unique dual-interfacial electric fields at the Au/ZIS and ZIS/Co3O4 interfaces enable directional and spatially separated migration of photogenerated electrons and holes to Au and Co3O4, respectively. As a result, Au/ZIS/Co3O4 achieves a remarkable H2 evolution rate of 2012.4 µmol g−1 h−1, with 67.2% of DFF yield and excellent recyclability, which is 7.7 times higher than blank Zn3In2S6 (260.4 µmol g−1 h−1). This H2 yield rate is the highest among reported photocatalysts for concurrent HMF valorization and H2 production. Furthermore, the intrinsic quantum efficiency of the system is quantitatively evaluated for the first time by solving the radiative transfer equation in a tubular photoreactor. This work demonstrates a generalizable strategy for engineering redox-site-separated photocatalysts for biomass valorization and solar hydrogen production, offering valuable insights into the design principles of next-generation photocatalytic systems for sustainable energy.