Product Distributions of Fischer‐Tropsch Synthesis over Core‐Shell Catalysts: The Effects of Diverse Shell Thickness

Abstract

AbstractA series of core‐shell catalysts with different shell thickness were synthesized and the effect of microporous silica shell on product distribution of Fischer‐Tropsch synthesis was analyzed. Fe3O4 core was prepared by hydrothermal method and the amorphous SiO2 shell was coated on the Fe3O4 core by sol‐gel method. N2 adsorption‐desorption analysis indicated an irregular and microporous silica shell and the pore size distribution moved to smaller diameter with the shell thickness increased. In Fischer‐Tropsch synthesis, inactive silica shell increased catalytic activity (FTY) and stability by restricting catalyst cracking and sintering. Product distribution shifted to C1‐C4 gaseous hydrocarbons with the increasing shell thickness probably due to the diffusion limitations on reactants/products and structure confinement and separation effect of microporous silica shell on restricting the growth of catalytic active particles. Selectivities of C5+ were restricted within 10% for core‐shell catalysts. WGS reaction activity is reduced as well, which constrains side reaction and amplifies FTS catalytic productivity to hydrocarbons.