Promoting the performance of catalytic systems by incorporating small amount of alkali has been proved effective for several reactions whilst controversial outcomes are reported for the synthetic natural gas production. This work studies a series of Ni catalysts for CO₂ and CO methanation reactions. In-situ DRIFTS spectroscopy evidenced similar reaction intermediates for all evaluated systems and it is proposed a reaction mechanism based on: i) formate decomposition and ii) hydrogenation of lineal carbonyl species to methane. Compared to bare Ni, the enhanced CO₂ methanation rates attained by NiFe/Al and NiFeK/Al systems are associated to promoted formates decomposition into lineal carbonyl species. Also for CO methanation, the differences in the catalysts’ performances were associated to the relative concentration of lineal carbonyl species. Under CO methanation conditions and opposing the CO₂ methanation results where the incorporation of K delivered promoted catalytic behaviours, worsened CO methanation rates were discerned for the NiFeK/Al system.

通过掺入少量 碱来提高催化系统的性能已被证明对几种反应有效，而据报道合成天然气生产的结果有争议。这项工作研究了一系列 用于 CO ₂ 和 CO 甲烷化反应的 Ni 催化剂。原位DRIFTS 光谱证明了所有评估系统的反应中间体相似，并提出了一种基于以下反应的机制：i) 甲酸盐分解和 ii) 线性羰基物种氢化为甲烷。与裸镍相比，NiFe/Al 和 NiFeK/Al 系统获得的提高的 CO ₂甲烷化率与促进      甲酸盐分解成线性羰基物种。同样对于 CO 甲烷化，催化剂性能的差异与线性羰基物种的相对浓度有关。在 CO 甲烷化条件下，与 CO ₂ 甲烷化结果相反，其中 K 的掺入促进了催化行为，发现 NiFeK/Al 系统的 CO 甲烷化率变差。