The methanation reaction of CO₂ is in discussion to be a sustainable pathway to address future questions arising from limited primary energy feedstock and the accumulation of CO₂ in the atmosphere. Therefore, the development of highly active and thermostable catalysts for this reaction is an indispensable matter of research. For this reason, an equimolar NiAlO_x benchmark catalyst (44 wt.% Ni loading) was synthesized and modified by doping with Fe or Mn up to 10 wt.% of promoter by co-precipitation at constant pH 9. Their activity and stability performances in the CO₂ methanation reaction were evaluated by comparing the conversion versus temperature characteristics before and after an aging period of 32 h at 500 °C. Material characterization studies comprising BET, XRD, in situ IR spectroscopy, XPS, H₂ and CO₂ chemisorption, and EPR/FMR contributed to derive structure-activity relationships and to obtain a deeper understanding of the catalytic behavior. Promotion with Mn led to a significant enhancement of the catalytic activity. This is assumed to be caused by a higher density of medium basic sites and an enhanced CO₂ adsorption capacity on the activated catalyst related to interactions between Mn oxide species and the mixed oxide phase, in combination with a stabilization of the Ni surface area at moderate Mn loadings. Promotion with Fe increased the thermal stability of the catalyst, which is attributed to the formation of a Ni-Fe alloy during catalyst activation. For both phenomena, the optimum molar Ni to promoter ratio for co-precipitated catalysts was found to be around 5.

在讨论中，CO ₂的甲烷化反应将是一条可持续的途径，以解决由于有限的一次能源原料和CO ₂在大气中的积累而引起的未来问题。因此，开发用于该反应的高活性和热稳定的催化剂是不可或缺的研究内容。因此，通过在恒定pH 9下共沉淀，通过掺入Fe或Mn最多达10 wt％的助催化剂，合成并改性了等摩尔的NiAlO _x基准催化剂（Ni含量为44 wt％）。在CO _2中通过在500°C下老化32小时之前和之后的转化率与温度特性进行比较，来评估甲烷化反应。包括BET，XRD，原位红外光谱，XPS，H ₂和CO ₂化学吸附以及EPR / FMR在内的材料表征研究有助于推导结构-活性关系并获得对催化行为的更深入了解。用Mn促进导致催化活性的显着提高。假定这是由于较高的中等碱性位点密度和增强的CO _2引起的与Mn氧化物种类和混合氧化物相之间的相互作用相关的活化催化剂上的吸附容量，以及在中等Mn负载下Ni表面积的稳定化。用铁促进提高了催化剂的热稳定性，这归因于在催化剂活化过程中形成了镍铁合金。对于这两种现象，共沉淀催化剂的最佳摩尔镍与助催化剂比率均约为5。