Electrocatalytic Hydrogenation Boosted by Surface Hydroxyls-Modulated Hydrogen Migration over Nonreducible Oxides

The migration of atomic hydrogen species over heterogeneous catalysts is deemed essential for hydrogenation reactions, a process closely related to the catalyst's functionalities. While surface hydroxyls-assisted hydrogen spillover is well documented on reducible oxide supports, its effect on widely-used nonreducible supports, especially in electrocatalytic reactions with water as the hydrogen source, remains a subject of debate. Herein, a nonreducible oxide-anchored copper single-atom catalyst (Cu₁/SiO₂) is designed and uncover that the surface hydroxyls on SiO₂ can serve as efficient transport channels for hydrogen spillover, thereby enhancing the activated hydrogen coverage on the catalyst and favoring the hydrogenation reaction. Using electrocatalytic dechlorination as a model reaction, the Cu₁/SiO₂ catalyst delivers hydrodechlorination activity 42 times greater than that of commercial Pd/C. An integrated experimental and theoretical investigation elucidates that surface hydroxyls facilitate the spillover of hydrogen intermediates formed at the Cu sites, boosting the coverage of active hydrogen on the surface of the Cu₁/SiO₂. This work demonstrates the feasibility of surface hydroxyls acting as transport channels for hydrogen-species to boost hydrogen spillover on nonreducible oxide supports and paves the way for designing advanced selective hydrogenation electrocatalysts.