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

Copper oxide-based materials show promising activity in biomass electrooxidation. However, systematic study of active sites evolution under electrochemical condition was rarely studied. In this work, we report copper oxide undergoes potential-dependent structure evolution with successive formation of Cu(OH)2 and CuOOH, which exhibit distinct activities in electrocatalytic glucose oxidation. [Display omitted] 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 Cu2+/Cu+ and Cu3+/Cu2+ 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.