RuCo/ZrO₂ Tandem Catalysts with Photothermal Confinement Effect for Enhanced CO₂ Methanation

Photothermal CO₂ methanation reaction represents a promising strategy for addressing CO₂-related environmental issues. The presence of efficient tandem catalytic sites with a localized high-temperature is an effective pathway to enhance the performance of CO₂ methanation. Here the bimetallic RuCo nanoparticles anchored on ZrO₂ fiber cotton (RuCo/ZrO₂) as a photothermal catalyst for CO₂ methanation are prepared. A significant photothermal CO₂ methanation performance with optimal CH₄ selectivity (99%) and rate (169.93 mmol g_cat ^-1 h^-1) is achieved. The photothermal energy of the RuCo bimetallic nanoparticles, confined by the infrared insulation and low thermal conductivity of the ZrO₂ fiber cotton (ZrO₂ FC), provides a localized high-temperature. In situ spectroscopic experiments on RuCo/ZrO₂, Ru/ZrO₂, and Co/ZrO₂ indicate that the construction of tandem catalytic sites, where the Co site favors CO₂ conversion to CO while incorporating Ru enhances CO^* adsorption for subsequent hydrogenation, results in a higher selectivity toward CH₄. This work opens a new insight into designing tandem catalysts with a photothermal confinement effect in CO₂ methanation reaction.