Oxygen vacancy-mediated photothermal CO2 methanation over Ni/Ce-Zr solid solution catalysts

C e-e Zr solid solution formation strengthens the metal-support interaction. • The catalyst reached 79.02% CO 2 conversion and methanation rate 26.35 mmol·g cat −1 ·h −1 . • Dual-role oxygen vacancies enhance charge separation and CO 2 activation. Photothermal Carbon dioxide (CO 2 ) hydrogenation is a promising strategy for solar-fuel production, but its performance is often limited by inefficient charge separation and poor low-temperature activity. Herein, Ni/Ce-Zr solid solution catalysts were developed by introducing lattice distortion to regulate the electronic structure and generate abundant oxygen vacancies. The resulting oxygen vacancies promote charge separation, enhance CO 2 activation, and strengthen the photothermal synergistic effect. Among the catalysts, 20Ni/Ce 0.75 Zr 0.25 O 2 exhibited the best performance, achieving 79.02% CO 2 conversion, over 99.00% CH 4 selectivity, a methanation rate of 26.35 ± 0.05 mmol·g cat −1 ·h −1 , and an apparent activation energy of 16.23 ± 0.70 kJ/mol at 250 °C, while maintaining stable operation for over 180 h. In situ DRIFTS results reveal that abundant oxygen vacancies facilitate the hydrogenation of key intermediates and suppress carbonate accumulation, thereby preventing catalyst deactivation. These findings demonstrate that oxygen-vacancy engineering is an effective approach for improving photothermal CO 2 methanation and provide guidance for the design of efficient solar-driven CO 2 conversion catalysts. Oxygen Vacancy-Mediated Photothermal CO 2 Methanation over Ni/Ce-Zr Solid Solution. Download: Download high-res image (208KB) Download: Download full-size image