Experimental and theoretical insights into an enhanced CO2 methanation mechanism over a Ru-based catalyst

Converting excessive CO 2 emissions from industrial operation into methane (CH 4 ) is critical for the remediation of global warming. However, this reaction requires a high temperature to overcome the high thermodynamic stability of CO 2 . The development of efficient catalysts for the CO 2 methanation reaction at low temperature remains challenging. Here we report that when a TiO 2 photothermal catalyst is loaded with Ru nanoparticles, the CO 2 to CH 4 conversion efficiency is markedly enhanced under light illumination. In fact, the CO 2 performance was enhanced fourfold and twofold from those of the traditional thermal catalytic reaction at 200°C and 250°C, respectively. In-situ DRIFTS analysis revealed that light irradiation accelerates the transition of bicarbonate to formates via light-induced charge carriers. Moreover, theoretical calculations revealed that photo-induced electron transfer effectively promotes H 2 dissociation and CO 2 activation on the Ru atoms. This work provides new theoretical insights into CO 2 activation and methanation under light illumination. • Ru/TiO 2 is 4× (200°C) and 2× (250°C) more catalytic after photo-induced heating. • Enhancing factors are prolonged charge lifetime and narrowed bandgap of Ru/TiO 2 . • Ru active sites accept electrons from the photoexcited TiO 2 supports under light. • Electron-rich Ru promotes H 2 dissociation, CO 2 activation, conversion of intermediates.