Bismuth atom tailoring of indium oxide surface frustrated Lewis pairs boosts heterogeneous CO₂ photocatalytic hydrogenation.

Abstract

The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H₂ and CO₂ molecules and enable efficient gas-phase CO₂ photocatalysis. Lattice engineering of metal oxides provides a useful strategy to tailor the reactivity of SFLPs. Herein, a one-step solvothermal synthesis is developed that enables isomorphic replacement of Lewis acidic site In³⁺ ions in In₂O₃ by single-site Bi³⁺ ions, thereby enhancing the propensity to activate CO₂ molecules. The so-formed Bi_xIn_2-xO₃ materials prove to be three orders of magnitude more photoactive for the reverse water gas shift reaction than In₂O₃ itself, while also exhibiting notable photoactivity towards methanol production. The increased solar absorption efficiency and efficient charge-separation and transfer of Bi_xIn_2-xO₃ also contribute to the improved photocatalytic performance. These traits exemplify the opportunities that exist for atom-scale engineering in heterogeneous CO₂ photocatalysis, another step towards the vision of the solar CO₂ refinery.