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

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.