Bimetallic AuCu/TiO ₂ Catalysts for Direct Oxidation of Sucrose to Gluconic Acid and Derivatives

Direct oxidation of sucrose to gluconic acid is important in the field of biomass conversion. However, the conversion of sucrose still poses challenges, primarily due to issues with catalyst activity and stability. In this work, we reported synergistic bimetallic AuCu/TiO2 catalysts for the facile oxidation of sucrose in an aqueous medium. The electronic coupling at the Au-CuO interface results in a record high productivity of gluconic acid (23,509 mol/molAu/h) at 100 °C in base-free medium. Surface characterization further reveals the insertion of Cu2+ species into the TiO2 matrix, resulting in a narrowing of the band gap and facilitating the activation of molecular O2 for aqueous oxidation of sucrose. The catalytic performances for bimetallic AuCu/TiO2 catalysts with varied particle sizes and compositions have been investigated, where it is found that the composition of CuO species in Au-CuO structures serves as the key factor determining the intrinsic activity of AuCu/TiO2 catalysts. This work provides valuable insights into the development of efficient catalysts regarding the conversion of sucrose into value-added chemicals for biorefineries.