The hydrogenation of CO₂ to methane with renewable H₂ can mitigate the greenhouse effect and realize the sustainable energy production. The SiO₂ supported Ni catalysts were prepared via a simple combustion-impregnation method. Highly dispersed Ni particles were obtained, accompanied by increased H₂ and CO₂ adsorption capacity. And the Ni active sites and the catalyst adsorption capacity to H₂ and CO₂ were modified by different promoters (La, Ce, or Mg). La and Ce were conducive to Ni dispersion and catalyst reducibility, bringing in more active sites and further enhanced catalytic activity at low temperatures. Conversely, the slight agglomeration of Ni particles and reduced catalyst reducibility were found on the catalyst with Mg, resulting from the formation of solid solution. Moreover, Mg atoms were prone to enrich on the surface of catalyst, which may cover part of Ni active sites and make them inaccessible. Therefore, though the largest H₂ and CO₂ adsorption capacity were achieved on the catalyst with Mg, it displayed the poor catalytic performance. Hence, the importance of the Ni active sites on the low-temperature activity of catalyst in CO₂ methanation was confirmed in this work. Besides, the increased CO₂ activation ability benefiting from the promoter could facilitate the catalytic activity at low temperatures. The fundamental findings in this work may help develop an efficient Ni-based catalyst for CO₂ methanation at low temperatures.

_{用可再生的H 2}将CO ₂加氢为甲烷可以减轻温室效应，实现能源的可持续生产。SiO ₂负载Ni催化剂通过简单的燃烧-浸渍法制备。获得了高度分散的Ni颗粒，同时增加了H ₂和CO ₂的吸附能力。_{以及Ni活性位点和催化剂对H 2}和CO ₂的吸附能力被不同的促进剂（La、Ce 或 Mg）修饰。La和Ce有利于Ni的分散和催化剂的还原性，带来更多的活性位点，进一步提高了低温下的催化活性。相反，在含 Mg 的催化剂上发现 Ni 颗粒的轻微团聚和降低的催化剂还原性，这是由于形成了固溶体。此外，Mg原子容易富集在催化剂表面，可能覆盖部分Ni活性位点，使其难以接近。因此，尽管在含Mg的催化剂上实现了最大的H ₂和CO ₂吸附容量，但它表现出较差的催化性能。_{因此，Ni活性位点对催化剂在CO 2}中低温活性的重要性在这项工作中证实了甲烷化。此外，促进剂提高的CO ₂活化能力可以促进低温下的催化活性。这项工作的基本发现可能有助于开发一种高效的镍基催化剂，用于低温下的 CO _{2甲烷化。}