Heterostructure Engineering of a Reverse Water Gas Shift Photocatalyst.

To achieve substantial reductions in CO emissions, catalysts for the photoreduction of CO into value-added chemicals and fuels will most likely be at the heart of key renewable-energy technologies. Despite tremendous efforts, developing highly active and selective CO reduction photocatalysts remains a great challenge. Herein, a metal oxide heterostructure engineering strategy that enables the gas-phase, photocatalytic, heterogeneous hydrogenation of CO to CO with high performance metrics (i.e., the conversion rate of CO to CO reached as high as 1400 µmol g cat h) is reported. The catalyst is comprised of indium oxide nanocrystals, InO (OH) , nucleated and grown on the surface of niobium pentoxide (NbO) nanorods. The heterostructure between InO (OH) nanocrystals and the NbO nanorod support increases the concentration of oxygen vacancies and prolongs excited state (electron and hole) lifetimes. Together, these effects result in a dramatically improved photocatalytic performance compared to the isolated InO (OH) material. The defect optimized heterostructure exhibits a 44-fold higher conversion rate than pristine InO (OH) . It also exhibits selective conversion of CO to CO as well as long-term operational stability.