Atomically dispersed Pt on CeO₂ promotes selective photocatalytic imine synthesis coupled with H₂O₂ evolution

Single-atom catalysts (SACs) have emerged as a promising class of photocatalysts, offering maximized atomic efficiency and tunable electronic structures. Herein, we report a CeO₂ nanorod-supported catalyst with atomically dispersed Pt sites (Pt₁/CeO₂-R), which exhibits exceptional performance in the photocatalytic oxidative coupling of benzyl alcohol and aniline under blue light (420 nm) irradiation. Compared with Pt nanoparticles and pristine CeO₂, this system exhibits significantly enhanced activity, efficiently promoting imine formation under mild conditions. Mechanistic studies reveal that atomically dispersed Pt enhances charge separation and facilitates the generation of reactive species (e.g., •O₂⁻ and carbon radicals), which are essential for driving the oxidative coupling reaction. Notably, the in situ generation of H₂O₂ suggests the possibility of an oxygen atom transfer pathway, complementing the radical-mediated reaction mechanism. Furthermore, density functional theoretical calculations indicate that the atomically dispersed Pt sites improve catalytic performance and selectivity by enhancing charge delocalization, optimizing adsorption thermodynamics, and reducing the activation energies of C–H and O–H bond cleavage to 0.05 eV and 0.18 eV, respectively. This study highlights the potential of CeO₂-supported SACs for achieving highly efficient and selective photocatalytic transformations, offering a sustainable strategy for advancing the synthesis of fine chemicals.