Cobalt Species Confined in N-Doped Graphdiyne for Divergent Aerobic Oxidation of Benzyl Alcohol Derivatives

Selective aerobic oxidation of alcohols into value-added chemicals is an important yet challenging reaction in sustainable catalysis. Here, we synthesize nanoflower-structured Co/NGDY by high-temperature pyrolysis under an NH₃ atmosphere. Co/NGDY exhibits excellent catalytic performance for the oxidation of benzyl alcohol under mild conditions, with air as the sole oxidant. Benefitting from strong Co–C and Co–N interactions, Co nanoparticles are uniformly embedded in the NGDY framework, creating abundant interfacial active sites and defect-rich carbon environments. By simply varying the reaction medium, Co/NGDY enables the selective synthesis of benzoic acid, benzonitrile, or methyl benzoate with up to 99% conversion and selectivity. Mechanistic analyses reveal that nitrogen doping modulates the electronic structure of Co to facilitate oxygen activation at the metal–carbon interface, driving the consecutive oxidation of the key benzaldehyde intermediate. The hierarchical nanoflower morphology facilitates mass transport and increases the exposure of active sites, while the strong coupling between Co species and the NGDY framework endows Co/NGDY with outstanding recyclability.