Dual Active Sites of Ni‐O‐Ti on NiTiO 3 Coated Ni for Efficient and Robust Photothermal CO 2 Methanation

ABSTRACT Converting CO 2 into value‐added fuels using a Ni‐based core–shell catalyst is beneficial for addressing the carbon deposition‐induced deactivation of Ni. However, designing highly active shells is critical. In this study, nickel titanate‐coated metallic Ni nanoparticles (Ni@NiTiO 3 ) are synthesized via laser‐induced nonequilibrium reaction. The obtained Ni@NiTiO 3 as a photothermal catalyst for converting CO 2 to CH 4 achieves a high CH 4 yield of 1.48 mol g cat −1 h −1 and CH 4 selectivity of 94.3% under the light intensity of 2.52 W cm −2 . The outstanding catalytic performance is ascribed to the presence of the Ni‐O‐Ti structure with dual active sites in the shell of Ni@NiTiO 3 . Specifically, Ni 2+ species in the Ni‐O‐Ti structure enhance CO 2 adsorption and activation, while Ti species stabilize high‐valent Ni species to maintain activity. Meanwhile, the metallic Ni core reduces the energy barrier for H 2 dissociation on the shell surface, thus facilitating the subsequent CO 2 hydrogenation. In a flow reactor (weight hourly space velocity of 200 000 mL g cat −1 h −1 ), Ni@NiTiO 3 achieves 77.1% CO 2 conversion and maintains long‐term stability for 100 h, which can also be efficiently driven under sunny conditions. This work demonstrates the design concept of core–shell catalyst with a highly active shell prepared via laser‐induced nonequilibrium reactions for efficient photothermal catalytic CO 2 hydrogenation reactions.