Isomorphic Cu‐Doped Ag Nanoclusters for Water‐Modulated Conversion of Propargylic Alcohols and CO 2 to Cyclic Carbonates or α‐Hydroxy Ketones

Developing a single catalytic system capable of producing distinct high‐value products from the same feedstock under mild conditions remains a formidable challenge. Here, we report a heterogeneous catalyst based on a copper‐doped silver nanocluster (Ag 3 Cu 2 /CNT) engineered via isomorphic doping. Its unique structure features fully exposed Ag─Cu dual sites, with its core innovation lying in the highly efficient catalysis of the water‐modulated conversion of propargylic alcohols and CO 2 , selectively yielding cyclic carbonates (98%) under anhydrous conditions or α‐hydroxy ketones (96.8%) with added water, both with record turnover numbers (>19 000) at gram scale. Crucially, through atomic‐precision paired comparison with an isostructural Ag 5 /CNT, we directly attribute the superior performance to synergistic Ag─Cu sites, where Cu preferentially anchors the alkyne group. Combined spectroscopic, intermediate‐trapping, and computational studies reveal that water modulates the reaction pathway, while the instability of the undoped Ag 5 cluster stems from dynamic Ag─S bond cleavage. This work establishes a scalable catalytic platform and provides a general design strategy—isomorphic heteroatom doping coupled with site exposure—for constructing predictable, tunable, and stable heterogeneous cluster catalysts.