Site-Tailored bimetallic Co-Ce catalyst on N-Doped carbon for highly selective hydrodeoxygenation of vanillin

The efficient conversion of lignin-derived oxygenates into fuels and high-value chemicals is pivotal for the development of renewable energy systems. A central challenge lies in the selective cleavage of the inherently recalcitrant C-O bonds in bio-oil model compounds under mild conditions. In this study, a multi-interface Co-Ce catalyst supported on nitrogen-doped carbon was successfully constructed via a bimetallic synergy and metal-organic framework (MOF)-derived strategy. The introduction of Ce exerted a multifunctional synergistic effect beyond that of a conventional promoter, realizing multi-scale modulation of the catalyst structure and performance. It modulated the electronic structure of Co active sites, thereby optimizing reactant adsorption and H₂ activation. Also, it suppressed the agglomeration of Co nanoparticles, thereby enhancing metal dispersion. Concurrently, it significantly increased the concentration of oxygen vacancies on the support surface, which collaboratively provided abundant active sites. Furthermore, it guided the formation of a hierarchical pore architecture conducive to mass transfer. Through this precise design and regulation of the active site microenvironment, the optimal catalyst achieved 100 % conversion of the model compound vanillin with 100 % selectivity toward 2-methoxy-4-methylphenol (MMP) under mild conditions, while also exhibiting excellent cycling stability and broad substrate applicability. This work not only demonstrates catalytic performance rivaling that of noble metals through the efficient synergy between non-noble metals (Ce and Co) but, more importantly, elucidates the underlying mechanism for the selective cleavage of C-O bonds.