Heterostructure Engineering of a Reverse Water Gas Shift Photocatalyst

Abstract To achieve substantial reductions in CO 2 emissions, catalysts for the photoreduction of CO 2 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 2 reduction photocatalysts remains a great challenge. Herein, a metal oxide heterostructure engineering strategy that enables the gas‐phase, photocatalytic, heterogeneous hydrogenation of CO 2 to CO with high performance metrics (i.e., the conversion rate of CO 2 to CO reached as high as 1400 µmol g cat −1 h −1 ) is reported. The catalyst is comprised of indium oxide nanocrystals, In 2 O 3− x (OH) y , nucleated and grown on the surface of niobium pentoxide (Nb 2 O 5 ) nanorods. The heterostructure between In 2 O 3− x (OH) y nanocrystals and the Nb 2 O 5 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 In 2 O 3− x (OH) y material. The defect optimized heterostructure exhibits a 44‐fold higher conversion rate than pristine In 2 O 3− x (OH) y . It also exhibits selective conversion of CO 2 to CO as well as long‐term operational stability.