Synergistic role of Cu⁰-Cu⁺ sites and oxygen vacancies on MOF-derived Cu supported CeO₂ for enhancing hydrogenation of cyclohexyl acetate to cyclohexanol

Unraveling the synergistic interplay between Cu⁰/Cu⁺ and support sites in Cu-based catalysts, coupled with oxygen vacancy-mediated active site modulation and their impact on hydrogenation performance metrics, remains a critical challenge in heterogeneous catalysis. Herein, we engineered a family of MOF-derived Cu/CeO₂ catalysts with tunable Cu loadings and oxygen vacancy(O_V) concentrations, featuring Cu⁰-Cu⁺-O_V interfacial sites, through a MOF-mediated pyrolysis strategy. Operando DRIFTS, XPS, and Raman analyses revealed dynamic restructuring of active sites during hydrogenation of cyclohexyl acetate. The optimized catalyst achieved 98.0 % substrate conversion and 97.3 % cyclohexanol selectivity at 250 ℃ under 3 MPa H₂, exhibiting a TOF 2.8-fold higher than conventional Cu/CeO₂. The results indicate that the superior catalytic performance of Cu/CeO₂-MOF should be attributed to the synergistic effects of Cu⁺, Cu⁰, and O_V. This synergy enhances the ability of catalysts to adsorb and activate cyclohexanone, as well as its hydrogen dissociation capability. Further analysis indicates that O_V exerts a direct influence on product selectivity. Moreover, the concentration of O_V modulates the ratio of Cu⁺/(Cu⁺+Cu⁰), which significantly affects conversion efficiency of the reaction. This work introduces an innovative approach to designing the electronic structure of copper-based catalysts, thereby optimizing the hydrogenation reactions of carbonyl compounds.