Surfactant‐Free Sol–Gel Synthesis Method for the Preparation of Mesoporous High Surface Area NiO–Al2O3 Nanopowder and Its Application in Catalytic CO2 Methanation

A group of nickel‐based catalysts with different weight percentages of Ni are synthesized using a novel surfactant‐free sol–gel method, and the prepared catalysts are used in the methanation of carbon dioxide. The results indicate that the surfactant‐free sol–gel method is highly effective to prepare nickel‐based catalysts with high Brunauer–Emmett–Teller (BET) area in the range of 269.2–297.3 m 2 g −1 . The increment in nickel content from 15 to 30 wt% increases the size of the Ni crystals from 3.7 to 4.2 nm, weakens the interaction between nickel oxide and alumina, and improves the reducibility of the catalysts. The catalyst with 30 wt% Ni possesses the best catalytic performance in CO 2 methanation reaction with 73.98% CO 2 conversion and 99% CH 4 selectivity at 350 °C. High catalytic stability is also observed for these catalysts.