Reaction-Induced Phase Engineering of CuCo Nanoparticles for Enhanced Photothermal CO2 Hydrogenation.

Photothermal CO2 hydrogenation is a promising approach for the conversion and valorization of CO2 into value-added products. However, challenges remain in balancing catalytic activity, selectivity, and stability, particularly for non-noble metal catalysts. In this work, a phase engineering strategy is introduced to synthesize CuCo heterophase nanoparticles via in situ photoreduction of oxide precursors under CO2 hydrogenation conditions. Experimental characterization reveals that the abundant Cu-Co3Cu interfaces act as atomic-level channels for photoelectron transfer and localized hot charge accumulation. These features synergistically improve full-spectrum light utilization and photothermal conversion efficiency. The optimal catalyst achieves a CO yield of 0.82 mol g-1 h-1 under 3 W cm-2 full-spectrum light illumination and maintains ≈95% selectivity across 100 cycles. In situ spectroscopy combined with theoretical calculations suggests that the phase engineering enhances CO2 adsorption and activation while weakening CO binding, thereby suppressing methanation and enabling an optimal Sabatier balance. This interfacial engineering approach in heterophase nanostructures improves both stability and activity of non-noble metal catalysts in CO2 conversion and offers an effective pathway for developing efficient photothermal systems through rational interfacial engineering.