Light-driven CO 2 methanation over Au-grafted Ce 0.95 Ru 0.05 O 2 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