Heterostructure Engineering of a Reverse Water Gas Shift Photocatalyst

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.