Inverse CeO2/Ni catalysts for efficient diphenyl ether hydrogenolysis: Role of metal–oxide interface in C–O bond cleavage

• The inverse CeO 2 /Ni catalyst exhibits superior activity for diphenyl ether hydrogenolysis. • Strong metal–support interactions enhance the Ce 3+ concentration and oxygen vacancies. • Achieved >90% DPE conversion and high selectivity under mild conditions (1 MPa, 150 °C). • DFT revealed that oxygen vacancies at the CeO 2 /Ni interface lower the C–O bond activation barriers. The selective cleavage of C–O bonds in lignin-derived model compounds is a crucial step toward the valorization of renewable biomass into value-added chemicals and fuels. Inverse catalysts featuring oxide nanoparticles or overlayers supported on metallic surfaces offer a unique configuration for investigating metal–oxide interfacial effects. In this study, we demonstrated that an inverse CeO 2 /Ni catalyst synthesized via a hydrothermal method exhibited superior activity towards the hydrogenolysis of diphenyl ether (DPE), a representative lignin model compound, compared to the conventional Ni/CeO 2 catalyst. Powder X-ray diffraction confirmed the formation of the inverse CeO 2 /Ni catalyst, as evidenced by the preserved cubic fluorite structure of CeO 2 and characteristic metallic Ni reflections. The H 2 -TPR and H 2 -TPD results indicate that the inverse catalyst exhibits stronger metal–support interactions and enhanced hydrogen activation compared to conventional Ni/CeO 2 . X-ray photoelectron spectroscopy (XPS) confirmed a higher Ce 3+ fraction, while Raman spectroscopy revealed an increased concentration of oxygen vacancies in the inverse CeO 2 /Ni catalyst. Catalytic performance tests demonstrated that the inverse CeO 2 /Ni catalyst achieved high DPE conversion (>90%) under mild reaction conditions (1 MPa H 2 , 150 °C) with high selectivity toward cyclohexanol and cyclohexane. Density functional theory (DFT) calculations further showed that oxygen vacancies at the CeO 2 /Ni interface facilitate DPE adsorption and lower the activation barriers for C–O bond cleavage relative to Ni/CeO 2 . These findings establish key structure–activity relationships for inverse CeO 2 /Ni catalysts and provide mechanistic insights that are directly relevant to the design of efficient catalysts for lignin-related hydrogenolysis reactions under mild conditions.