Visible-Light-Driven Photocatalytic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over Plasmonic Au/ZnO Catalyst

Photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is an environmental friendly way to convert platform molecules into high-value chemicals. Here, Au/ZnO catalysts with different oxygen vacancies were fabricated by the deposition precipitation method and were used for the photocatalytic oxidation of HMF to FDCA under visible light irradiation. All of the Au/ZnO catalysts showed excellent photocatalytic oxidation selectivity to FDCA greater than 90% under mild conditions. The Au/ZnODP-H catalyst treated by H2 afforded the highest HMF conversion and the selectivities of FDCA up to 96.9%. The localized surface plasmon resonance effect of Au nanoparticles, oxygen vacancy, and the existence of the Schottky barrier enhance the separation and transfer efficiency of photogenerated electron–hole pairs of the catalyst, so as to enhance its photocatalytic activity. The active species trapping experiment and electron spin resonance analysis showed that •O2– and h+ were the active species responsible for the oxidation reaction. The recycle experiment also proved that the catalyst has good stability. This work provides a new strategy for the design of photocatalysts for converting biomass into high-value chemicals.