Fe3O4纳米催化剂的制备及其F-T合成性能研究

基于溶剂热合成体系,制备了不同形貌的Fe₃O₄微球和纳米片催化剂,考察了水热合成条件对Fe₃O₄晶粒形貌的影响,并研究了Fe₃O₄纳米催化剂的费托合成(F-T)性能。结果表明,成核和晶体生长速率是控制Fe₃O₄晶体形貌的关键。与传统的沉淀铁催化剂相比,Fe₃O₄纳米催化剂更容易还原和向活性相转变,因此,具有更高的F-T反应活性、低碳烯烃选择性及C₅₊选择性;Fe₃O₄微球催化剂比纳米片催化剂更易维晶粒的稳定,具有更高的反应活性和稳定性。

Preparation of nano-structured Fe3O4 catalysts and their performance in Fischer-Tropsch synthesis

Two shape-defined nano-structured Fe₃O₄ catalysts such as Nano-Microsphere (FNM) and Nano-Flake (FNF) were prepared by a simple solvothermal method. The effects of precursor type on Fe₃O₄ crystal morphology was studied. It is found that the rate of nucleation and crystal growth have a crucial influence on the particle morphology. Compared to the traditional Fe catalyst, the shape-defined nano Fe₃O₄ catalysts could be easily reduced and transferred into active phases, resulting in higher Fischer-Tropsch synthesis (F-T) activity and C₅₊ selectivity. Especially, the FNM catalyst displayed higher catalytic activity and stability than the FNF catalyst. It was found that the FNF catalyst was more favorable to agglomeration because of shape change of the flakes. In addition, the results indicate that the hydrocarbon selectivity is strongly affected by the particle morphology.