Promoters, such as Na and Mn, play an important role in governing the active phase and catalytic performance of cobalt-based FTS catalyst. In this work, the dependence of the promotional effect of promoters on supports has been investigated by using the carbon and silica supported cobalt-based catalysts in the presence of Na, Mn, and both Na and Mn promoters, respectively. The characterization results of H₂-TPR, CO-TPD and XRD profiles together with the FTS performances demonstrate the strong dependence of the promotional effect of promoter on the type of support used. The carbon support, which shows weak cobalt-support interaction, facilitates the manifestation of the effect of promoter. In detail, Mn can promote the formation of Co₂C sites at the conditions of 260 °C, 0.5 MPa and lower H₂/CO ratio, resulting from the promoted CO adsorption and subsequent dissociation. Thus, the suppressed adsorption of H₂ and the promoted surface dissociative C* concentration enhances the selectivities to lower olefins (C₂⁼-C₄⁼) and C₅₊ with a decrease in methane selectivity. Interestingly, the further addition of Na promoter shows synergistic effect of Na and Mn promoter on remarkably increasing selectivity to lower olefins due to the obviously suppressed chain growth. This synergistic effect could be observed only at the weak cobalt-carbon interaction with a more obvious effect at lower H₂/CO ratio in feed gas that favors the increase of Co₂C sites with mainly exposed facets of (111) and (020). The presence of (020) facet might be more crucial to enhance the formation of lower olefins. However, over silica support with strong cobalt-silica interaction, the promotional effect of Mn is obviously suppressed, which leads to only CoO and metallic Co sites in the FTS reaction and much weaker impact on product selectivity. The further addition of Na into Mn-promoted cobalt catalysts shows similar effect as Na promoter alone in the product selectivity where the chain growth is highly promoted to remarkably suppress methane selectivity and enhance selectivity to C₅₊ rather than desired lower olefins. In contrast to carbon support, the strong cobalt-silica interaction leads to less promotional formation of CO₂ via the Boudouard reaction (2CO*→C* + CO₂) due to the increased non-dissociative adsorption of CO.

Na和Mn等促进剂在控制钴基FTS催化剂的活性相和催化性能方面起着重要作用。在这项工作中，已经通过在Na，Mn以及Na和Mn两种促进剂的存在下分别使用碳和二氧化硅负载的钴基催化剂研究了促进剂对载体的促进作用的依赖性。H ₂ -TPR，CO-TPD和XRD谱的表征结果以及FTS性能表明，启动子的促进作用强烈依赖于所用支持物的类型。碳载体显示出弱的钴-载体相互作用，促进了促进剂作用的表现。详细地讲，Mn可以促进Co ₂的形成。C的位置在260°C，0.5 MPa和更低的H ₂ / CO比的条件下，这归因于促进的CO吸附和随后的离解。因此，抑制的H ₂吸附和提高的表面离解C *浓度提高了对低级烯烃（C ₂ ⁼ -C ₄ ⁼）和C _5+的选择性，同时降低了甲烷的选择性。有趣的是，由于明显抑制了链增长，进一步加入Na助催化剂显示出Na和Mn助催化剂的协同作用，显着提高了对低级烯烃的选择性。仅在弱的钴-碳相互作用下才能观察到这种协同作用，而在较低的H ₂下则观察到更明显的作用。进料气中的/ CO比有利于增加主要暴露于（111）和（020）面的Co ₂ C位点。（020）面的存在对于增强低级烯烃的形成可能更为关键。但是，在具有强钴-硅相互作用的二氧化硅载体上，Mn的促进作用明显受到抑制，这导致FTS反应中仅产生CoO和金属Co位置，对产物选择性的影响要弱得多。将Na进一步添加到Mn促进的钴催化剂中，在产物选择性方面表现出与单独使用Na促进剂相似的效果，其中高度促进链增长以显着抑制甲烷选择性并增强对C _5+的选择性而不是所需的低级烯烃。与碳载体相反，由于钴的非解离吸附增加，强的钴-二氧化硅相互作用导致通过Boudouard反应（2CO *→C * + CO ₂）的CO ₂促进形成较少。