摘要
采用等体积浸渍法分别以乙醇和水为溶剂制备了Co/SBA-15催化剂,通过N2物理吸附、X射线衍射和程序升温还原等方法对催化剂进行了表征,并在固定床反应器中评价了催化剂的费托合成反应性能.结果表明,乙醇浸渍制备的催化剂钴粒子尺寸较小,金属钴分散度较高,钴粒子与载体之间的相互作用较强,还原温度较高,其费托合成反应活性和高碳烃选择性高于水溶液浸渍制备的催化剂.
SBA-15-supported cobalt （5%） catalysts were prepared by incipient wemess impregnation with aqueous and ethanol solution of cobalt nitrate. The Co/SBA-15 catalysts were characterized by N2 physisorption, X-ray diffraction, and temperature-programmed reduction. The catalytic performance of the catalysts for Fischer-Tropsch （F-T） synthesis was evaluated in a fixed-bed reactor. Lower surface tension of ethanol is helpful to retain cobalt species in mesopores of the SBA-15 support during the drying process. As a result, the surface area and pore volume decrease, and the average pore diameter increases more remarkably for the catalyst prepared with ethanol solution of cobalt nitrate. Compared with the catalyst prepared with aqueous solution of cobalt nitrate, the catalyst prepared with ethanol solution of cobalt nitrate has smaller particle size of Co304 and higher dispersion of cobalt metal. The smaller Co304 particles in the catalyst prepared with ethanol solution of cobalt nitrate interact strongly with the SBA-15 support and are reduced at higher temperature. The catalyst prepared with ethanol solution of cobalt nitrate exhibits higher initial activity and higher selectivity for C5＋ hydrocarbon in F-T synthesis. However, the activity of the catalyst decreases more rapidly during the F-T synthesis reaction than the catalyst prepared with aqueous solution of cobalt nitrate.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2009年第9期901-906,共6页
关键词
乙醇浸渍
钴基催化剂
SBA-15分子筛
费托合成
孔结构
ethanol impregnation
cobalt-based catalyst
SBA-15 molecular sieve
Fischer-Tropsch synthesis
pore structure
