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A series of Ni-xSi/ZrO₂ (x = 0, 0.1, 0.5, 1 wt%, the controlled contents of Si) catalysts with a controlled nickel content of 10 wt% were prepared by the co-impregnation method with ZrO₂ as support and Si as a promoter. The effect of different amounts of Si on the catalytic performance was investigated for CO₂ methanation with the stoichiometric H₂/CO₂ molar ratio (4/1). The catalysts were characterized by BET, XRF, H₂-TPR, H₂-TPD, H₂-chemisorption, CO₂-TPD, XRD, TEM, XPS, and TG-DSC. It was found that adding the appropriate amount of Si could improve the catalytic performance of Ni/ZrO₂ catalyst at a low reaction temperature (250 °C). Among all the catalysts studied, the Ni-0.1Si/ZrO₂ catalyst showed the highest catalytic activity, with H₂ and CO₂ conversion of 73.4% and 72.5%, respectively and the yield of CH₄ was 72.2%. Meanwhile, the catalyst showed high stability and no deactivation within a 10 h test. Adding the appropriate amount of Si could enhance the interaction between Ni and ZrO₂, and increase the Ni dispersion, the amounts of active sites including surface Ni⁰, oxygen vacancies, and strong basic sites on the catalyst surface. These might be the reasons for the high activity and selectivity of the Ni-0.1Si/ZrO₂ catalyst.