Light-driven CO2 methanation over Au-grafted Ce0.95Ru0.05O2 solid-solution catalysts with activities approaching the thermodynamic limit

Photothermal CO 2 methanation offers a clean and sustainable solution to store intermittent renewable energy as synthetic CH 4 . However, its high reaction temperature and low space-time yield hinder its industrial application. Here we report an Au/Ce 0.95 Ru 0.05 O 2 solid-solution catalyst exhibiting a remarkable photothermal CO 2 methanation activity approaching the thermal catalysis limit under visible–near-infrared light irradiation without external heating. Localized surface-plasmon-induced hot-electron injection created abundant oxygen vacancies near the dispersed ruthenium sites, accelerating CO 2 methanation. An approximately 6- to 8-fold increase in the pre-exponential factor was evidenced using Arrhenius plot analysis under visible–near-infrared light irradiation. Using a flow reactor, a photothermal CH 4 production rate of 473 mmol g cat − 1 h − 1 was obtained at a gas hourly space velocity of 80 , 000 ml g cat − 1 h − 1 with ~100% CH 4 selectivity, ~75% single-pass CO 2 conversion and excellent durability. Our study offers insights into plasmonic-steered photochemistry, which may open opportunities for the high-yielding synthesis of carbon-based chemicals using solar energy. CO 2 methanation offers a route to synthetic methane production but typically requires high temperatures to achieve sufficient rates. This study presents light-driven CO 2 methanation on an Au/Ce 0.95 Ru 0.05 O 2 solid-solution catalyst with high CH 4 production rate and selectivity benefiting from synergistic photochemical and photothermal effects.