Single‐Atom Pt Anchored Polyoxometalate as Electron‐Proton Shuttle for Efficient Photoreduction of CO2 to CH4 Catalyzed by NiCo Layered Doubled Hydroxide

Abstract The crucial role of active hydrogen (H*) in photocatalytic CO2 methanation has long been overlooked, although recently, accelerating proton‐coupled electron transfer (PCET) processes to enhance CH4 productivity and selectivity has garnered significant attention. Herein, a single‐atom Pt‐anchored H3PMo12O40 (Pt1‐PMo12) is applied as an efficient proton–electron shuttle to facilitate the photocatalytic performance of NiCo layered double hydroxide (NiCo‐LDH). The resultant Pt1‐PMo12@NiCo‐LDH exhibited superior CH4 productivity (723 µmol g−1 h−1) with CH4 selectivity of 82.3%, showcasing a 24.9 times productivity enhancement over NiCo‐LDH (29 µmol g−1 h−1). Systematic investigations revealed that abundant H* is generated by the dissociation of H2O on Pt1 sites and stored within Pt1‐PMo12. Subsequently, the multiple H* rapidly migrated from Pt1‐PMo12 to the catalytic sites on NiCo‐LDH by the engineered strong Mo─O─Ni/Co bonds, thereby significantly expediting the PCET process. The in situ DRIFTS and theoretical calculations elucidated that the Pt1‐PMo12 decreased the energy barrier for *CO protonation to *CHO (0.38–0.18 eV) and optimized the rate‐determining step of *CH3 to *CH4 (0.64 eV), thus promoting highly active and selective CH4 generation. This work provided novel insights into achieving efficient photocatalytic CO2 methanation by modulating the fast generation and transport of active H*.