Unraveling the potential-dependent structure evolution in CuO for electrocatalytic biomass valorization

Electrocatalytic oxidation of renewable biomass (such as glucose) into high-value-added chemicals provides an effective approach to achieving carbon neutrality. CuO-derived materials are among the most promising electrocatalysts for biomass electrooxidation , but the identification of their active sites under electrochemical conditions remains elusive. Herein, we report a potential-dependent structure evolution over CuO in the glucose oxidation reaction (GOR). Through systematic electrochemical and spectroscopic characterizations, we unveil that CuO undergoes Cu 2+ /Cu + and Cu 3+ /Cu 2+ redox processes at increased potentials with successive generation of Cu(OH) 2 and CuOOH as the active phases. In addition, these two structures have distinct activities in the GOR, with Cu(OH) 2 being favorable for aldehyde oxidation, and CuOOH showed faster kinetics in carbon–carbon cleavage and alcohol/aldehyde oxidation. This work deepens our understanding of the dynamic reconstruction of Cu-based catalysts under electrochemical conditions and may guide rational material design for biomass valorization.