This study aimed to investigate impacts of Al₂O₃ and SiO₂, the supports of Ni catalysts with distinct properties, and the additive of La on catalytic behaviors and reaction intermediates formed during methanation of CO₂. The results showed that the addition of La to either Ni/Al₂O₃ or Ni/SiO₂ led to the reduced size of metallic nickel, the reduced reduction degree of nickel oxide, the increased alkalinity number and the increased activity for methanation of CO₂. Furthermore, the addition of La to the Ni/SiO₂ catalyst could suppress the formation of CO via the reverse water gas shift (RWGS) reaction. Ni/SiO₂ was much more active than the Ni/Al₂O₃, even though nickel size was much bigger. The in situ Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS) studies showed that the addition of La to Ni/Al₂O₃ interfered with integration of hydroxyl group with *CO₂ species and formation of the bicarbonate and carbonate, while favored formation of the formate specie, enhancing the catalytic activity. For Ni/SiO₂, instead of formate, CO* became the main reaction intermediate. The strong absorption of CO* favored its further conversion and explained the low selectivity of the silica-based catalysts toward CO. The addition of La to Ni/SiO₂ catalyst facilitated further hydrogenation of CO* species to CH₄ and promoted the catalytic activity.

这项研究旨在研究Al ₂ O ₃和SiO ₂，具有不同性能的Ni催化剂的载体以及La的添加对CO ₂甲烷化过程中形成的催化行为和反应中间体的影响。结果表明，将La添加到Ni / Al ₂ O ₃或Ni / SiO _2中导致金属镍的尺寸减小，氧化镍的还原度减小，碱度数增加和CO的甲烷化活性增加。₂。此外，将La添加到Ni / SiO ₂催化剂中可以通过逆水煤气变换（RWGS）反应抑制CO的形成。镍/二氧化硅₂比的Ni / Al的活性高得多₂ ö ₃，即使镍大小是大得多。原位漫反射红外傅里叶变换光谱（DRIFTS）研究表明，向Ni / Al ₂ O _3中添加La会干扰羟基与* CO _2的结合以及碳酸氢盐和碳酸盐的形成，同时有利于碳酸氢盐和碳酸氢盐的形成。甲酸盐，增强催化活性。对于Ni / SiO ₂，代替甲酸酯，CO *成为主要的反应中间体。CO *的强吸收有助于其进一步转化，并解释了二氧化硅基催化剂对CO的选择性低。向Ni / SiO _2中添加La催化剂促进了CO *物种进一步加氢成CH ₄并提高了催化活性。