Enhanced fischer-tropsch synthesis performance on Co@SiO2 catalyst with core-shell structure

Abstract

Energy is of great importance for the development of modern society, which is mostly dependent on crude oil. Due to the severe pollution caused by using crude oil and the diminishing of crude oil reserves, it is urgent to look for clean oil from alternative resource other than crude oil. Currently, Coal-to-Liquid (CTL) or Biomass-to-Liquid (BTL) technology is an important way to produce clean liquid fuels through Fischer-Tropsch Synthesis (FTS) of syngas. For FTS process, catalyst is a main factor for affecting on syngas conversion and product distribution. For traditional oxides-supported catalysts, the mutual constraint between active metal loading and dispersion at high metal loading is hard to overcome, which will hinder the synthesis of high-performance FTS catalysts. In this paper, a new type of Co@SiO2-T (CS-T) and Co@SiO2-X (CS-X) catalysts with core-shell structure were prepared by using polyvinyl pyrrolidone (PVP) as the structural stabilizer, hexadecyl trimethyl ammonium Bromide (CTAB) as the templating agent and tetraethyl orthosilicate (TEOS) as the silica source. The effects of hydrothermal temperature and pyrolysis temperature on the catalyst physical-chemical properties and FTS performance were investigated. The results showed that increasing the hydrothermal temperature favored the formation of the core-shell structure of the catalysts. With the increase of pyrolysis temperature, the catalyst particle size decreased from 0.54 μm to 0.23 μm. The FTS activities of the catalysts showed a volcano trend with hydrothermal and pyrolysis temperatures.