Accelerating Heterojunctions Interfacial Charge‐Transfer via Single‐Atom Bridges for Enhancing Photocatalytic CO ₂ ‐to‐CH ₄ Conversion

Abstract Heterojunction photocatalysts still face numerous challenges in achieving efficient interfacial charge transfer. Herein, a novel strategy of a single‐atom bridge is developed at heterojunction interfaces to provide the shortest and most direct channel for electrons to shuttle across the interface at the atomic scale. Specifically, palladium single‐atom (Pd _SA ) bridges with an [O‐Pd‐N] coordination structure are constructed at the interface of polydopamine (PDA) composited tianium dioxide (TiO ₂ ) photocatalyst (PDA/Pd _SA /TiO ₂ ) for photocatalytic carbon dioxide (CO ₂ ) reduction to methane (CH ₄ ). The PDA/Pd _SA /TiO ₂ exhibits a high selectivity of 98.13% for CH ₄ production with a rate of 37.28 µmol g ⁻¹ h ⁻¹ without any additives. A comparison between experimental and theoretical calculations reveals that the O‐Pd‐N single‐atom bridge functions as an efficient charge‐transfer highway, dramatically accelerating the interfacial charge transfer kinetics and optimizing charge transfer efficiency. Moreover, the abundant hydrophilic groups in PDA promote the adsorption and dissociation of H ₂ O and increase the coverage of ^* H, thus significantly enhancing CH ₄ selectivity. This study underscores the critical role of precisely designed single‐atom charge‐transfer bridges at heterojunction interfaces, demonstrating a promising platform for the development of highly efficient heterojunction photocatalysts for selective CO ₂ methanation.