Photothermal Catalyst Engineering: Hydrogenation of Gaseous CO₂ with High Activity and Tailored Selectivity

Abstract

This study has designed and implemented a library of hetero-nanostructured catalysts, denoted as Pd@Nb₂O₅, comprised of size-controlled Pd nanocrystals interfaced with Nb₂O₅ nanorods. This study also demonstrates that the catalytic activity and selectivity of CO₂ reduction to CO and CH₄ products can be systematically tailored by varying the size of the Pd nanocrystals supported on the Nb₂O₅ nanorods. Using large Pd nanocrystals, this study achieves CO and CH₄ production rates as high as 0.75 and 0.11 mol h^-1 g_Pd^-1, respectively. By contrast, using small Pd nanocrystals, a CO production rate surpassing 18.8 mol h^-1 g_Pd^-1 is observed with 99.5% CO selectivity. These performance metrics establish a new milestone in the champion league of catalytic nanomaterials that can enable solar-powered gas-phase heterogeneous CO₂ reduction. The remarkable control over the catalytic performance of Pd@Nb₂O₅ is demonstrated to stem from a combination of photothermal, electronic and size effects, which is rationally tunable through nanochemistry.