Photodriven Catalytic Hydrogenation of CO to CH with Nearly 100% Selectivity over Ag Clusters.

The conversion of chemically inert carbon dioxide and its photoreduction to value-added products have attracted enormous attention as an intriguing prospect for utilizing the principal greenhouse gas CO. Herein, we explore the use of Ag clusters with well-defined atomic structures for high-selectivity photocatalytic hydrogenation of CO to methane. Ag clusters, with molecular-like properties and surface plasmon resonance, exhibit competitive catalytic activity for light-driven CO reduction that yield an almost 100% product selectivity of methane at a relatively mild temperature (100 °C). DFT calculations reveal that the absorption of CO on Ag clusters is energetically favorable. The methanation of the Ag cluster catalyst has been investigated by infrared spectroscopy, verifying that methane was produced through a -H-assisted multielectron reaction pathway via the transformation of formyl and formaldehyde species to form surface CH. This work presents a highly efficient strategy for high-performance CO methanation via well-defined metal cluster catalysts.