Expediting *OH accumulation kinetics on metal-organic frameworks-derived CoOOH with CeO2 “accelerator” for electrocatalytic 5-hydroxymethylfurfural oxidation valorization

In this work, nickel foam supported CeO₂-modified CoBDC (BDC stands for terephthalic acid linker) metal-organic frameworks (NF/CoBDC@CeO₂) are prepared by hydrothermal and subsequent impregnation methods, which can be further transformed to NF/CoOOH@CeO₂ by reconstruction during the electrocatalytic test. The obtained NF/CoOOH@CeO₂ exhibits excellent performance in electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) because the introduction of CeO₂ can optimize the electronic structure of the heterointerface and accelerate the accumulation of *OH. It requires only a potential of 1.290 V_RHE to provide a current density of 50 mA cm⁻² in 1.0 M KOH + 50 mM HMF, which is 222 mV lower than that required in 1.0 M KOH (1.512 V_RHE). In addition, density-functional theory calculation results demonstrate that CeO₂ biases the electrons to the CoOOH side at the heterointerface and promotes the adsorption of *OH and *HMF on the catalyst surface, which lower the reaction energy barrier and facilitate the electrocatalytic oxidation process.