The commercial application of cobalt-based Fischer-Tropsch synthesis (FTS) suffers from catalyst deactivation. One of the main deactivation mechanisms under industrial conditions is sintering. In this work, we explored the role of manganese oxide as a structural promoter against sintering in a carbon nanofiber supported cobalt model catalyst. We employed in situ Mössbauer emission spectroscopy to study cobalt sintering in synthesis gas as a function of the steam partial pressure, which mimics high CO conversion during FTS. Steam accelerates the sintering of non-promoted metallic cobalt particles. Model experiments point to a synergistic effect between carbon monoxide and steam on cobalt sintering. In the mangense-promoted case, sintering is significantly reduced, indicative of the structural stabilization of small cobalt particles by manganese oxide. Nevertheless, a fraction of cobalt particles in close interaction with manganese oxide carburized under these conditions, resulting in a lower catalytic activity.

钴基费托合成（FTS）的商业应用受到催化剂失活的影响。工业条件下的主要失活机制之一是烧结。在这项工作中，我们探索了氧化锰作为结构促进剂在碳纳米纤维负载钴模型催化剂中的作用，以防止烧结。我们就地雇用穆斯堡尔发射光谱研究合成气中钴的烧结与蒸汽分压的关系，模拟了 FTS 期间的高 CO 转化率。蒸汽加速非促进金属钴颗粒的烧结。模型实验表明一氧化碳和蒸汽对钴烧结的协同作用。在锰促进的情况下，烧结显着减少，表明氧化锰使小钴颗粒的结构稳定。然而，在这些条件下，与氧化锰密切相互作用的一小部分钴颗粒会渗碳，导致催化活性降低。