Design of Single Gold Atoms on Nitrogen-Doped Carbon for Molecular Recognition in Alkyne Semi-Hydrogenation.

Single-atom heterogeneous catalysts with well-defined architectures are promising for deriving structure-performance relationships, but the challenge lies in finely tuning the structural and electronic properties of the metal. To tackle this point, a new approach based on the surface diffusion of gold atoms on different cavities of N-doped carbon is presented. By controlling the activation temperature, the coordination neighbors (Cl, O, N) and the oxidation state of the metal can be tailored. Semi-hydrogenation of various alkynes on the single-atom gold catalysts displays substrate-dependent catalytic responses; structure insensitive for alkynols with γ-OH and unfunctionalized alkynes, and sensitive for alkynols with α-OH. Density functional theory links the sensitivity for alkynols to the strong interaction between the substrate and specific gold-cavity ensembles, mimicking a molecular recognition pattern that allows to identify the cavity site and to enhance the catalytic activity.