Effects of Pore Size of Ru-SiO₂ Catalysts Prepared by Alkoxide Method on Fischer-Tropsch Reaction

Abstract

Uniform pore sizes of 10 wt Ru _ SiO2 catalysts prepared by the alkoxide method were varied in the range of 4-8 nm, by adding formamide (FA) at the sol-gel preparation stage. The prepared catalysts were used to catalyze the Fischer-Tropsch (F-T) reaction in the slurry phase under the reaction conditions of T 503 K, P 1 MPa, H2/CO 2/1, and W/ W/ W F 5 g-catal.h/mol. The Ru particle sizes estimated by H2 adsorption increased with increasing pore size, although the Ru crystallite sizes evaluated by XRD line broadening were only slightly changed. The selectivity for CH4 decreased and the selectivity for higher hydrocarbons increased with increasing pore size of the catalysts, caused by diffusivity of the slurry solvent and/or the products in the uniform meso-pores, or uniform Ru particle size effects.

Effects of Pore Size of Ru-Al₂O₃ Catalysts Prepared by Alkoxide Method on Fischer-Tropsch Reaction

“…The crystallite size increased with the pore diameter (Dp), and L was always larger than Dp. This relationship was already discussed previously 12) . The time courses of the F-T reaction are illustrated in Fig.…”

Development of Novel Catalysts for Fischer–Tropsch Synthesis: Tuning the Product Selectivity

“…Only very few studies have contributed to elucidating the effect of pore size of support on the catalytic behavior of Feand Ru-based catalysts. Okabe et al [150] investigated 10 wt % Ru/SiO 2 catalysts with average pore sizes changing from 4 to 8.4 nm for FT synthesis in slurry-phase reactions. Whereas CO conversion remained almost unchanged, the selectivity to CH 4 decreased and that to C 5 + increased with increasing the pore size.…”

Mesoporous Silica-Supported Metal Oxide-Promoted Rh Nanocatalyst for Selective Production of Ethanol from Syngas

“…(Figure. 1b) The change of selectivity could be attributed to the diffusivity of gas and/or products in the meso-pores of carbonaceous materials. 20 If the diffusion rate is high enough, the heat produced from the extremely exothermic CO hydrogenation on the active sites might be removed effectively through the well-ordered pores, resulting in prevention of local overheating inside the catalyst. In addition, owing to the hydrophobic nature of carbonaceous materials, the hydrophilic products such as methanol, ethanol and propanol could be easily transported through the catalyst system.…”