Coupling Transition Metal Chalcogenides with Metal Nanoclusters for Steering Photoredox Catalysis

Metal nanocluster (NC)-mediated photocatalytic CO₂ conversion is an emerging avenue for achieving carbon neutrality, yet it remains underexplored due to the ultrashort charge lifespan of metal NCs. To surmount this obstacle, metal NC/transition metal chalcogenide (TMC) heterostructures are constructed via a ligand-initiated electrostatic self-assembly buildup. In this meticulously designed nanoarchitecture, glutathione (GSH)-protected metal NCs [Au_<i>x</i>@GSH, Au₂₂(GSH)₁₈, Ag₉(GSH)₆, Ag₁₆(GSH)₉, Ag₃₁(GSH)₁₉] are uniformly anchored on the two-dimensional (2D) TMC (CdS, ZnIn₂S₄, CdIn₂S₄, In₂S₃) framework, leading to well-defined metal NC/TMC composite photosystems. The favorable energy level alignment between these metal NCs and TMCs synergistically endows metal NC/TMC heterostructures with markedly increased photoredox activities, encompassing photocatalytic CO₂ reduction, H₂ production, and aromatic alcohol oxidation under visible light, far surpassing the corresponding pristine TMC counterparts. Alloy NCs (Au_<i>x</i>Ag_1-<i>x</i>, Au_<i>x</i>Cu_1-<i>x</i>)/TMCs are also constructed to demonstrate the universality of the heterostructures. The generation of a type II charge transport pathway between metal NCs and TMCs is unveiled to account for the photoredox mechanisms. Our work will provide an interesting idea for tuning charge transfer over metal NCs for photocatalysis.