The fundamental insights of the reaction mechanism, especially the synergistic effect between oxygen vacancies and basic sites, are highly promising yet challenging for Ru-based catalysts during carbon dioxide (CO₂) methanation. Herein, a series of Ru-based catalysts were employed to study the mechanism of CO₂ methanation. It is found that Ru/CeO₂ catalyst exhibits a much higher CO₂ conversion (86%) and CH₄ selectivity (100%), as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites. Additionally, the in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO₂ catalyst, and the b-HCOO* could be the key intermediate due to b-HCOO* is more easily hydrogenated to methane than m-HCOO*. The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO₂ methanation.

反应机制的基本见解，尤其是氧空位和碱性位点之间的协同效应，对于二氧化碳 (CO 2 ) 甲烷化过程中的 Ru 基催化剂来说非常有前途但也具_有挑战性。在此，采用一系列Ru基催化剂来研究CO ₂甲烷化的机理。结果发现，由于存在丰富的氧空位和弱碱性位点， Ru/CeO ₂催化剂表现出更高的CO ₂转化率(86%)和CH _{4选择性(100%)，以及30 h的优异稳定性。}此外，现场_{漫反射红外傅立叶变换光谱 (DRIFTS) 和密度泛函理论 (DFT) 计算表明，甲酸盐形成步骤主导了 Ru/CeO 2}催化剂的氢化路线，而 b-HCOO* 可能是关键中间体，因为 b-HCOO * 比 m-HCOO* 更容易氢化为甲烷。_{该系统研究标志着精确调整氧空位和碱性位点之间的协同关系对于实现 CO 2}甲烷化所需性能的重要性。