Visible and Near-Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO over Nanostructured Pd@NbO.

The reverse water gas shift (RWGS) reaction driven by NbO nanorod-supported Pd nanocrystals without external heating using visible and near infrared (NIR) light is demonstrated. By measuring the dependence of the RWGS reaction rates on the intensity and spectral power distribution of filtered light incident onto the nanostructured Pd@NbO catalyst, it is determined that the RWGS reaction is activated photothermally. That is the RWGS reaction is initiated by heat generated from thermalization of charge carriers in the Pd nanocrystals that are excited by interband and intraband absorption of visible and NIR light. Taking advantage of this photothermal effect, a visible and NIR responsive Pd@NbO hybrid catalyst that efficiently hydrogenates CO to CO at an impressive rate as high as 1.8 mmol gcat h is developed. The mechanism of this photothermal reaction involves H dissociation on Pd nanocrystals and subsequent spillover of H to the NbO nanorods whereupon adsorbed CO is hydrogenated to CO. This work represents a significant enhancement in our understanding of the underlying mechanism of photothermally driven CO reduction and will help guide the way toward the development of highly efficient catalysts that exploit the full solar spectrum to convert gas-phase CO to valuable chemicals and fuels.