Yuelun Wang

Effect of preparation methods on the catalytic properties of Co/SBA-15 catalysts for Fischer-Tropsch synthesis

Abstract The influence of different preparation methods (conventional incipient wetness impregnation, vacuum impregnation, vacuum impregnation then ammonia deposition) on the physico-chemical and catalytic properties of mesoporous Co/SBA-15 catalysts for the Fischer-Tropsch synthesis has been investigated. These catalysts were characterized by N 2 adsorption-desorption, X-ray diffraction (XRD), Temperature-programme reduction (TPR), High resolution transmission electron microscope (HRTEM). Co/SBA-15 catalyst prepared by conventional incipient wetness impregnation showed the higher CO conversion, lower CH 4 selectivity and higher C 5 + selectivity, which was attributed to the higher reduction degrees of the larger Co 3 O 4 particles. Co/SBA-15 catalysts prepared by vacuum impregnation and vacuum impregnation then ammonia deposition showed smaller cobalt particles, which led to lower reducibility and lower activity, higher CH 4 selectivity and lower C 5 + selectivity.

Effect of cobalt introduction order over Co/SiO2 sol–gel catalysts for Fischer–Tropsch synthesis

Sol–gel Co/SiO2 catalysts were prepared using Co–en (ethylenediamine) complex precursors with different cobalt introduction order. More highly reduced catalysts were obtained by gelling the silica support followed by depositing cobalt nanoparticles on silica surface, and then catalysts exhibited higher FT activity and concomitant higher C18+ selectivity. Meanwhile, both series of catalysts prepared with en/Co molar ratio of 2/1 exhibited higher activity due to their high cobalt reduction.