La<sub>2</sub>O<sub>3</sub>–Modified Ni-Based\nCatalysts Supported on Ordered Mesoporous Silicas for CO<sub>2</sub> Methanation

Conversion\nof CO<sub>2</sub> into value-added chemicals\nis regarded\nas an effective way to reduce carbon emissions and improve the carbon\nrecycling economy. In the process of hydrogenation of CO<sub>2</sub> to CH<sub>4</sub>, nickel (Ni) has been extensively investigated\ndue to its promising activity and easy availability. However, the\ninferior performance at low temperatures of Ni-based catalysts and\nthe tendency of sintering at high temperatures lead to a rapid decline\nin activity, which hinders their large-scale applications. In this\nstudy, mesoporous silicas with highly ordered mesoporous structures\nbut different pore symmetries and textural properties have been investigated\nas supports to synthesize Ni-based catalysts modified by La<sub>2</sub>O<sub>3</sub>. The effect of mesoporous symmetries and textural properties\nof the silica support on catalytic performance has been reasonably\nrevealed. The catalysts supported on optimized silica with bicontinuous\nthree-dimensional cubic pore symmetry exhibit considerably enhanced\nactivity and stability in long-term CO<sub>2</sub> methanation, which\nis attributed to the high dispersion of metal particles and the better\nmass transfer performance of interconnected mesopores in the silica\nsupport.