J. Jia*+, A. Jelle*⁺, G. A. Ozin⁺ and D. D. Perovic*

* Department of Materials Science and Engineering, University of Toronto
⁺ Department of Chemistry, University of Toronto

Arising from the global energy demand and climate change, the conversion of greenhouse gas carbon dioxide into value-added chemicals and fuels is attracting increasing commercial attention. The crux for the successful development of this promising technology is the exploration and discovery of highly active, selective and stable catalysts. Herein we demonstrate that the photo-catalytic conversion of CO₂ can be driven by Nb₂O₅ nanorod-supported Pd nanocrystals, without external heating. We also demonstrate 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 to achieve a CO production rate surpassing 18.8 mol h^-1 gPd^-1 with 99.5% CO selectivity. These performance metrics establish a new milestone at the forefront 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. The insight gleaned from this detailed experimental-theoretical study provides a blueprint for how to tailor the performance metrics of earth-abundant low-cost metal-metal oxide (M@M'O_x) analogues.