A systematic study was carried out to investigate the promotion effect of manganese on the performance of a coprecipitated iron-manganese bimetallic catalyst for the light olefins synthesis from syngas. The catalyst s...A systematic study was carried out to investigate the promotion effect of manganese on the performance of a coprecipitated iron-manganese bimetallic catalyst for the light olefins synthesis from syngas. The catalyst samples were characterized by N2 physisorption, transmis- sion electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, powder X-ray diffraction （XRD）, Mossbauer spectroscopy, H2- differential thermogravimetric analysis （H2-DTG）, CO temperature-programmed reduction （CO-TPR） and CO2 temperature-programmed des- orption （CO2-TPD）. The Fischer-Tropsch synthesis （FTS） performance of the catalyst was measured at 1.5 MPa, 250 ℃ and syngas with H2/CO ratio of 2.0. The characterization results indicated that the addition of manganese decreases the catalyst crystallite size, and improves the catalyst BET surface area and pore volume. The presence of manganese suppresses the catalyst reduction and carburization in H2, CO and syngas, respectively. The addition of manganese improves the catalytic activity of water-gas shift reaction and suppresses the oxidation of iron carbides in the FTS reaction. The incorporation of manganese improves the catalyst surface basicity and results in a significant improvement in the selectivities to light olefins and heavy hydrocarbons （C5＋）, and furthermore an inhibition of methane formation in FTS. The pure iron catalyst （Mn-00） has the highest initial FTS catalytic activity （65%） and the lowest selectivity （17.35 wt%） to light olefins （C2=-C4=）. The addition of an appropriate amount of manganese can improve the catalyst FTS activity.展开更多
基金supported by Natural Science Foundation of Chongqing Three Gorges University (12ZD14)Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University
文摘A systematic study was carried out to investigate the promotion effect of manganese on the performance of a coprecipitated iron-manganese bimetallic catalyst for the light olefins synthesis from syngas. The catalyst samples were characterized by N2 physisorption, transmis- sion electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, powder X-ray diffraction （XRD）, Mossbauer spectroscopy, H2- differential thermogravimetric analysis （H2-DTG）, CO temperature-programmed reduction （CO-TPR） and CO2 temperature-programmed des- orption （CO2-TPD）. The Fischer-Tropsch synthesis （FTS） performance of the catalyst was measured at 1.5 MPa, 250 ℃ and syngas with H2/CO ratio of 2.0. The characterization results indicated that the addition of manganese decreases the catalyst crystallite size, and improves the catalyst BET surface area and pore volume. The presence of manganese suppresses the catalyst reduction and carburization in H2, CO and syngas, respectively. The addition of manganese improves the catalytic activity of water-gas shift reaction and suppresses the oxidation of iron carbides in the FTS reaction. The incorporation of manganese improves the catalyst surface basicity and results in a significant improvement in the selectivities to light olefins and heavy hydrocarbons （C5＋）, and furthermore an inhibition of methane formation in FTS. The pure iron catalyst （Mn-00） has the highest initial FTS catalytic activity （65%） and the lowest selectivity （17.35 wt%） to light olefins （C2=-C4=）. The addition of an appropriate amount of manganese can improve the catalyst FTS activity.
