Atom‐Precise Heteroatom Core‐Tailoring of Nanoclusters for Enhanced Solar Hydrogen Generation

Abstract While core–shell nanomaterials are highly desirable for realizing enhanced optical and catalytic properties, their synthesis with atomic‐level control is challenging. Here, the synthesis and crystal structure of [Au₁₂Ag₃₂(SePh)₃₀]⁴⁻, the first example of selenolated Au–Ag core–shell nanoclusters, comprising a gold icosahedron core trapped in a silver dodecahedron, which is protected by an Ag₁₂(SePh)₃₀ shell, is presented. The gold core strongly modifies the overall electronic structure and induces synergistic effects, resulting in high enhancements in the stability and near‐infrared‐II photoluminescence. The Au₁₂Ag₃₂ and its homometal analog Ag₄₄, show strong interactions with oxygen vacancies of TiO₂, facilitating the interfacial charge transfer for photocatalysis. Indeed, the Au₁₂Ag₃₂/TiO₂ exhibits remarkable solar H₂ production (6810 µmol g⁻¹ h⁻¹), which is ≈6.2 and ≈37.8 times higher than that of Ag₄₄/TiO₂ and TiO₂, respectively. Good stability and recyclability with minimal catalytic activity loss are additional features of Au₁₂Ag₃₂/TiO₂. The experimental and computational results reveal that the Au₁₂Ag₃₂ acts as an efficient cocatalyst by possessing a favorable electronic structure that aligns well with the TiO₂ bands for the enhanced separation of photoinduced charge carriers due to the relatively negatively charged Au₁₂ core. These atomistic insights will motivate uncovering of the structure–catalytic activity relationships of other nanoclusters.