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采用共沉淀法制备了La2O3掺杂的γ-Al2O3,并将其负载金属钴,制得了钴基费-托合成催化剂。用H2-程序升温还原、H2-程序升温脱附、氧滴定等技术对催化剂进行了表征。采用CO以及合成气为探针分子,用漫反射红外光谱法在原位条件下研究催化剂的吸附性能。在固定床反应器中测定了各催化剂的费-托合成反应性能。氧化镧的掺杂显著影响了催化剂的催化性能。共沉淀法掺杂氧化镧的载体负载钴后表现出更高的还原度、催化活性以及重质产物选择性。这是由于共沉淀法掺杂过程中,氧化镧进入到γ-Al2O3晶体四面体位中,占据三氧化二铝的四面体位,暴露出更多八面体位供主金属钴占据,从而具有更高的还原度及更好的催化性能。
La2O3-doped γ-Al2O3 was prepared by coprecipitation method and supported on metallic cobalt to prepare a cobalt-based Fischer-Tropsch synthesis catalyst. The catalyst was characterized by H2-temperature reduction, H2-temperature programmed desorption and oxygen titration. Using CO and syngas as probe molecules, the adsorption properties of the catalysts were investigated in situ using diffuse reflectance infrared spectroscopy. The Fischer-Tropsch synthesis reactivity of each catalyst was measured in a fixed bed reactor. Doping of lanthanum oxide significantly affects the catalytic performance of the catalyst. The coprecipitated lanthanum oxide doped support showed higher reducibility, catalytic activity and heavy product selectivity after supported cobalt. This is due to the coprecipitation method in which lanthanum oxide enters the tetrahedral sites of the γ-Al 2 O 3 crystal and occupies the tetrahedral sites of the aluminum oxide, exposing more octahedral sites for the dominant metallic cobalt to have higher Reduction degree and better catalytic performance.