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

Abstract

The effects of manganese salts on Ru/Mn/Al2O3 catalysts prepared by the impregnation method for FischerTropsch synthesis were investigated. The catalysts were named Ru/Mn(N)/Al2O3, Ru/Mn(A)/Al2O3, Ru/Mn(S)/ Al2O3 and Ru/Mn(Cl)/Al2O3 according to the manganese nitrate, manganese acetate, manganese sulfate and manganese chloride salts. In the slurry phase Fischer-Tropsch reaction, Ru/Mn(N)/Al2O3 showed high and stable catalytic performance for CO conversion and space time yield under the reaction conditions, whereas other catalysts were deactivated. The order of catalytic performance was Ru/Mn(N)/Al2O3Ru/Mn(A)/Al2O3 Ru/ Mn(Cl)/Al2O3 Ru/Mn(S)/Al2O3. The catalyst porosity, CO chemisorption, XRD, TEM, TPR and XPS were observed, which indicated that the similar size of Ru particle and pore diameter at 8 nm on Ru/Mn(N)/Al2O3 may increase the number of active Ru atoms on the catalyst surface due to the formation of manganese chloride, resulting in the high catalytic activity and stability for Fischer-Tropsch synthesis.