Controllable Conversion of CO2 on Non-Metallic Gold Clusters.

Gold nanoparticles in metallic or plasmonic state have been widely used to catalyze homogeneous and heterogeneous reactions. However, the catalytic behavior of gold catalysts in non-metallic or excitonic state remain elusive. Atomically precise Aun clusters (n=number of gold atoms) bridge the gap between non-metallic and metallic catalysts and offer new opportunities for unveiling the hidden properties of gold catalysts in the metallic, transition regime, and non-metallic states. Here, we report the controllable conversion of CO2 over three non-metallic Aun clusters, including Au9 , Au11 , and Au36 , towards different target products: methane produced on Au9 , ethanol on Au11 , and formic acid on Au36 . Structural information encoded in the non-metallic clusters permits a precise correlation of atomic structure with catalytic properties and hence, provides molecular-level insight into distinct reaction channels of CO2 hydrogenation over the three non-metallic Au catalysts.