Strong Interaction over Ru/Defects‐Rich Aluminium Oxide Boosts Photothermal CO₂ Methanation via Microchannel Flow‐Type System

The CO 2 methanation is an important component of the “power to gas” strategy, and the Ru‐Al 2 O 3 catalyst is considered to be a state‐of‐the‐art catalyst for this reaction. Conventional Ru‐Al 2 O 3 is prepared by wet impregnation. Due to weak interactions between Ru and the Al 2 O 3 , construction of a controllable interface between the metal and the substrate is still challenging. In this work, a UV pulse laser is used to controllably construct ultra‐small Ru nanoparticles on defects‐rich Al 2 O 3‐x ‐L in situ grown on Al foil (Ru‐Al 2 O 3‐x ‐L) for effective photothermal CO 2 methanation. The catkin‐like fluff Al 2 O 3‐x ‐L efficiently traps light to ensure the light adsorption of Ru‐Al 2 O 3‐x ‐L. The defects in Al 2 O 3‐x ‐L efficiently anchors Ru. A Strong‐Metal‐Support‐Interaction (SMSI) effect is constructed between the ultra‐small Ru nanoparticles and the Al 2 O 3‐x ‐L. The Ru‐Al 2 O 3‐x ‐L exhibits remarkable photothermal catalytic performance (CH 4 yield of 12.35 mol g Ru −1 h −1 ) in the closed batch system. Then an innovative flow reactor is established based on the one‐piece Ru‐Al 2 O 3‐x ‐L microchannel catalyst. Thanks to local pressure on the edge of the microchannels, the CH 4 yield is further enhanced to 14.04 mol g Ru −1 h −1 . Finally, an outdoor setup demonstrates the feasibility of photothermal CO 2 methanation (CH 4 yield of 18.00 mmol min −1 ). This work provides novel perspectives for the construction of multi‐level micro/nanostructures integrated catalysts for photothermal CO 2 methanation.