Tailoring Redox Active Sites with Dual‐Interfacial Electric Fields for Concurrent Photocatalytic Biomass Valorization and H ₂ Production

Abstract Light‐driven photocatalytic conversion of biomass‐derived substrates into value‐added chemicals, coupled with hydrogen (H ₂ ) 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/Zn ₃ In ₂ S ₆ /Co ₃ O ₄ (Au/ZIS/Co ₃ O ₄ ) photocatalyst is reported for selective dehydrogenation of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfuran (DFF), coupled with H ₂ generation. The unique dual‐interfacial electric fields at the Au/ZIS and ZIS/Co ₃ O ₄ interfaces enable directional and spatially separated migration of photogenerated electrons and holes to Au and Co ₃ O ₄ , respectively. As a result, Au/ZIS/Co ₃ O ₄ achieves a remarkable H ₂ 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 Zn ₃ In ₂ S ₆ (260.4 µmol g ⁻¹ h ⁻¹ ). This H ₂ yield rate is the highest among reported photocatalysts for concurrent HMF valorization and H ₂ 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.