Effects of Ruthenium Precursors on Ru/Mn/Al₂O₃ and Ru/Al₂O₃ Catalysts for Fischer-Tropsch Synthesis

Abstract

Ru/Mn/Al2O3 and Ru/Al2O3 catalysts, which prepared with various ruthenium precursors into impregnation method, were investigated for Fischer-Tropsch (FT) synthesis in a continuous stirred tank reactor; and the catalysts were characterized by H2-chemisorption, TPR, XRD, TEM and XPS. On the basis of Ru/Mn/Al2O3 catalysts, Ru(Cl)/Mn/Al2O3 prepared with ruthenium chloride exhibited much higher catalytic activity and stability than those on Ru(A)/Mn/Al2O3 and Ru(N)/Mn/Al2O3, which were prepared with ruthenium acetylacetonate and ruthenium nitrosyl nitrate precursors. The order of the CO conversion was Ru(Cl)/Mn/Al2O3 Ru(A)/Mn/Al2O3 Ru(N)/Mn/Al2O3. This order was also agreed with the order of CO conversion on Ru/Al2O3 in various ruthenium precursors. One explanation is in characterization results that the particle size of Ru and the pore diameter of the support such as 8 nm can be performed to influence high FT activity. On the other hand, over Ru(Cl)/Mn/Al2O3 and Ru(Cl)/Al2O3 catalysts, lower activity and higher deactivation rate with reaction time on Ru(Cl)/Al2O3 were clearly observed, where Ru(Cl)/Mn/Al2O3 showed high resistance to catalyst deactivation. In this observation, manganese chloride can be formed by removing chlorine atoms from ruthenium chloride, thus increasing the concentration of metallic Ru active species on the catalyst surface and with inhibiting catalyst deactivation.

Carbon dioxide conversion to fuel over alumina-supported ruthenium catalysts

“…The second but very small peak was also observed with its maximum at 268 °C before the last extended peak is observed with a maximum at about 667 °C. The first broad hydrogen reduction peak was attributed to RuO 2 reduction to Ru metallic state, while the small peak with its maximum at 268 °C could be associated with the reduction of ruthenium species which were in strong interaction with the Al 2 O 3 support [ 6 , 7 ]. The peak observed at 667 °C could represent reduction of some ruthenium species which are in strong interaction with the alumina support.…”

Effects of Manganese Salts on Ru/Mn/Al₂O₃ Catalytic Activity and Stability for Fischer-Tropsch Synthesis

“…Ru catalyst improves middle distillate yields and increases wax formation, which can be cracked into middle distillates in the presence of effective additives and supports on the catalyst. Catalyst preparation from ruthenium precursors by the impregnation method using ruthenium chloride can provide more suitable catalysts than other Ru precursors for high catalytic performance 26) . However, chlorine can form on the catalyst surface, resulting in catalyst deactivation in a slurry phase FT reactor 27)～29) .…”

Identifying the time-dependent predominance regimes of step and terrace sites for the Fischer–Tropsch synthesis on ruthenium based catalysts

“…However, there is a growing interest in Ru-based catalysts for the hydrogenation of CO and/or CO 2 . [3][4][5][6][7][8][9][10][11][12][13] When tested under similar reaction conditions, Rubased catalysts exhibit higher CO conversion rates and higher α values, i.e., a higher fraction of high molecular weight hydrocarbons, than Fe-or Co-based catalysts. 2,14,15 Furthermore, Ru-based catalysts can also operate in the presence of high partial pressures of water (the main co-product of the FTS re-action) and other oxygenate-containing atmospheres without deactivation, 16,17 making it possible to operate under mild reaction conditions in aqueous-phase slurry reactors.…”