Ce dissolution induced in situ generating oxygen defects of Co3O4 boosting electrocatalytic oxidation of 5-hydroxymethylfurfural

The dissolution of unstable metal atoms can form structures with more defects on the catalyst surface, which provides great feasibility for improving the intrinsic activity of catalyst. In this paper, it is proposed that the dissolution of doped Ce promotes the in-situ formation of oxygen vacancy in the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMFOR) process, which is conducive to the rate-determining step of dehydrogenation of the reaction intermediates, and thus accelerates the HMFOR. The Ce-Co3O4 exhibits excellent HMFOR performance with impressive HMF conversion (98.0%), 2,5-furandicarboxylic acid (FDCA) yield (95.48%), and Faradaic efficiency (97%) at 1.45 V vs. RHE. In situ Raman proved that the dissolution of doped Ce was accompanied by the formation of oxygen vacancy on the surface of Co3O4, and the in situ generated oxygen vacancy not only regulated the adsorption balance of *OH and HMF in the HMFOR process, but also promoted the formation of high valence cobalt. This in situ vacancy generation strategy provides a new reference for future directions in designing highly efficient electrocatalyst for biomass conversion.