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Ni/M/SiO2 catalyst (M=La, Ce or Mg) for CO2 methanation: Importance of the Ni active sites
Journal of CO2 Utilization ( IF 7.2 ) Pub Date : 2022-07-22 , DOI: 10.1016/j.jcou.2022.102150
Ming Song , Liluo Shi , Xuena Xu , Xihua Du , Yan Chen , Wenchang Zhuang , Xumei Tao , Limei Sun , Yan Xu

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.



中文翻译:

用于 CO2 甲烷化的 Ni/M/SiO2 催化剂(M=La、Ce 或 Mg):Ni 活性位点的重要性

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。

更新日期:2022-07-22
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