Boosting low-temperature CO₂ hydrogenation by photo-assistance over an inverse configuration of Cu-Y₂O₃ system

CO₂ hydrogenation over the metal-oxide catalytic system is an important strategy for carbon neutralization. It is crucial to enhance the low-temperature activity and lower the cost of the catalysts. In this work, we synthesized an inverse Y₂O₃/Cu catalyst for boosting the low-temperature reverse water-gas shift (LT-RWGS) reaction under thermal conditions with photo-assistance. The formed Y₂O₃/Cu interface, with distinct structural features compared to the conventional Cu/Y₂O₃ interface, lowers charge transfer resistance and narrows the bandgap, which is favorable for the separation of photo-generated carriers as well as the formation of photocurrent. Based on the results of in situ technology and theoretical calculations, an alternative reaction mechanism induced by inverse configuration under light conditions is identified. All these properties lead to superior activity of the LT-RWGS reaction with photo-assistance, in which CO₂ conversion reaches 12.9% with a CO selectivity of 100% at 250 °C and 0.5 W·cm⁻² of light irradiation, 2.7 times higher than that under pure thermal conditions and 8.4 times higher than that over Cu/Y₂O₃ under the same photo-assistance conditions. This work highlights the significance of an inverse catalyst in photothermal CO₂ conversion and provides an efficient way for enhancing the activity of CO₂ hydrogenation.