Light-mediated synergy boosts CO₂ conversion and suppresses CH₄ formation over Ni/Al₂O₃ in the photothermal RWGS...

The reverse water-gas shift (RWGS) reaction is considered an effective way to mitigate global warming by converting CO₂ into syngas on a large scale. However, when using Ni-based catalysts, the RWGS reaction is always accompanied by severe methanation, and achieving high CO selectivity while maintaining high activity remains a significant challenge. This study successfully achieved the regulation of CO₂ hydrogenation selectivity on Ni/Al₂O₃ by introducing light into the thermal catalytic system. The results showed that the CO selectivity of Ni(8)/Al₂O₃ (Ni loading of 8 wt%) increased from 60.5% to 99.9% under 1.5 W cm^-2 light irradiation (450 °C). Simultaneously, under light conditions, the CO₂ conversion of Ni(8)/Al₂O₃ was 71.1%, which was 2.0 times higher than that under dark conditions. Comparing the CO₂ consumption rate at different wavelengths, it was confirmed that the enhanced catalytic activity of Ni(8)/Al₂O₃ under illumination was mainly due to ultraviolet light. Combined transient experiments and in situ/operando spectroscopic characterization demonstrate that, compared to dark conditions, the introduction of light weakened the adsorption strength of the *CO intermediate on the catalyst surface, making it easier to desorb and form CO, thus significantly improving product selectivity. This study provides an innovative approach for regulating the selectivity of CO₂ hydrogenation products through light-induced modulation.