Morphology Engineering of γ‑Alumina Microgranules as Support of Cobalt Catalysts Used for Fischer–Tropsch Synthesis: An Effective Strategy for Improving Catalytic Performance

As a catalyst skeleton, the morphological design of support materials is definitely important since the performance of the catalyst is strongly influenced by the structural and textural properties of the support. Herein, an innovative scalable synthesis of γ-alumina microgranules was performed by designing a setup to combine sol–gel, oil-drop, and electrospray methods in order to study the effects of alumina microgranule morphology on cobalt catalyst performance for Fischer–Tropsch synthesis (FTS). Different drying conditions were applied to prepare γ-alumina support with different crystalline phases and morphological structures. Depending on the drying method of the hydrogel precursor, the structural and textural properties of the microgranules were improved. Cobalt catalysts were prepared by incipient wetness impregnation on alumina microgranules for FTS in the slurry phase and in a fixed bed reactor. The results showed that the change in the morphological properties of alumina affects its oxidation state in addition to affecting the distribution of cobalt nanoparticles. The two-dimensional structure aerogel nanosheets provide uniform distribution of the cobalt particles, while alumina xerogels exhibit significant shrinkage during the drying process, resulting in predominance of aggregation behavior on cobalt particles. This research focused on the development of ambigel as an effective intermediate of aerogel and xerogel for catalytic applications.