The active phase in cobalt-based Fischer-Tropsch synthesis

Advances in Selectivity Control for Fischer–Tropsch Synthesis to Fuels and Chemicals with High Carbon Efficiency

“…The particle size of the active phase is another major factor that should be carefully controlled to obtain a promising FTS catalytic performance. ,, The optimum particle size of Co 0 or Ru 0 is suggested to be in the range 6–10 nm, depending on the catalyst type and reaction conditions. ,, Typically, TOF and C 5+ selectivity increase with increasing particle size to a critical value and then remain almost unchanged with a further increase in particle size. As for the Fe-based case, the particle size effect of iron carbide remains ambiguous due to the facile phase transformation during the FT reaction. ,, To use Co more efficiently, an in situ embedded method was developed to prepare E-Co 3 O 4 @4SiO 2 catalyst with a Co particle size around 6.5 nm while enhancing Co loading to 34 wt % .…”

“…FTS catalysts have been well studied, and the key factors that affect the catalytic activity and heavy hydrocarbon selectivity have been systematically summarized in many review articles. ,,− , As for FT metal, only Fe, Co, and Ru show excellent catalytic performance for FTS, and Fe- and Co-based FT catalysts have been successfully applied in industry . Herein, we mainly highlight the latest advances in improving catalytic efficiency and C 5+ selectivity by finely tuning the active phase structure, particle size, promoters, and metal–support interface.…”

“…The active metal and phase are key factors to influence the catalytic behavior for the FT reaction. ,, Metallic Co and Ru with the hexagonal close-packed (HCP) phase are the optimum active phase for Co-based or Ru-based catalysts, respectively. Both Co-based and Ru-based catalysts are commonly employed at low temperature (200–250 °C) and mainly produce heavy hydrocarbons with C 5+ selectivity surpassing 90% and very limited selectivity to CH 4 and CO 2 , endowing them with the feature of high carbon efficiency.…”

“…Therefore, FTS technology has attracted substantial attention from academia and industry since having been first reported by Hans Fischer and Franz Tropsch in the 1920s . Normally, the primary target products of FTS are linear heavy hydrocarbons (also known as paraffins) . Olefins and trace of oxygenates can also be coproduced during the reaction process, especially for Fe-based FTS catalysts.…”

“…Another important characteristic of FTS is the removal of O atoms derived from CO dissociation in the form of H 2 O or CO 2 . For metallic Co and Ru with low intrinsic activity for the water–gas shift reaction (WGSR), H 2 O is the dominant O-containing product . For Fe-based or carbide-based catalysts, the high WGSR activity typically causes the coproduction of a large amount of CO 2 with selectivity in the range 30–50%, which would increase the energy consumption and equipment investment cost for the separation process. , The carbon utilization efficiency would be largely lowered to less than 50% when considering the total selectivity of undesirable C1 byproducts including CH 4 and CO 2 .…”