Accelerating alcohol oxidation kinetics for electrochemical biomass upgrading via photoinduced active CuIII-O generation

Copper-based compounds exhibit broad prospects in the electrocatalytic oxidation of biomass for sustainable production of high-value-added chemicals due to their passivated oxygen evolution reaction (OER) competitiveness. However, the sluggish reaction kinetics remain the main challenge in constraining their scalable application. Herein, a highly selective electrooxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-furandicarboxylic acid (FDCA) on CuO is achieved via photoinduced surface reconstruction. The experimental results confirmed that the photogenerated hole accumulation on the surface of CuO with matched valence band position can promote the CuOOH active phase generation. Density functional theory (DFT) calculations and the overall relationship between structure and selectivity indicate the CuOOH species can accelerate the spontaneous dehydrogenation process of hydroxyl group . Therefore, the activated CuO electrode under illumination can effectively regulate the conversion of 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) key intermediates and exhibits accelerated reaction kinetics, FDCA yield increased by 17.79 % compared to dark condition. Additionally, a general enhancement effect on the oxidation of benzyl alcohol and furfuryl alcohol was also revealed. This work introduces photoassistance effect for the first time in HMF oxidation, opening up prospects for the application of photoelectric synergy in biomass value-added conversion and providing insights into the activity mechanism of Cu-based catalysts in organic oxidation.