摘要
Co/Al2O3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), temperature programmed reduction (TPR), hydrogen temperature programmed desorption (H2-TPD) and O2 titration. Co-support compound formation can be detected in catalyst system by XRD. For the Co/Al2O3 catalysts with low cobalt loading, CoAl2O4 phase appears visibly. Two different reduction regions can be presented for Co/Al2O3 catalysts, which belong to Co3O4 crystallites (reduction at 320 ℃) and cobalt oxide-alumina interaction species (reduction at above 400 ℃). Increasing Co loading results in the increase of Co3O4 crystallite size. The reduced Co/Al2O3 catalysts have two adsorption sites, and cobalt loading greatly influences the adsorption behavior. With the increase of cobalt loading, the amount of low temperature adsorption is increased, the amount of high temperature adsorption is decreased, and the percentage reduction and cobalt crystallite size are increased.
Co/Al_2O_3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), temperature programmed reduction (TPR), hydrogen temperature programmed desorption (H_2-TPD) and O_2 titration. Co-support compound formation can be detected in catalyst system by XRD. For the Co/Al_2O_3 catalysts with low cobalt loading, CoAl_2O_4 phase appears visibly. Two different reduction regions can be presented for Co/Al_2O_3 catalysts, which belong to Co_3O_4 crystallites (reduction at 320 ℃) and cobalt oxide-alumina interaction species (reduction at above 400 ℃). Increasing Co loading results in the increase of Co_3O_4 crystallite size. The reduced Co/Al_2O_3 catalysts have two adsorption sites, and cobalt loading greatly influences the adsorption behavior. With the increase of cobalt loading, the amount of low temperature adsorption is increased, the amount of high temperature adsorption is decreased, and the percentage reduction and cobalt crystallite size are increased.
基金
Project(2 0 3730 90 )supportedbytheNationalNaturalScienceFoundationofChina
project(2 0 0 3ABB0 1 3)supportedbytheTalentedYoungScientistFoundationofHubeiProvince
projectsupportedbytheExcellentYoungTeachersProgramofMinistryofEducationofChina
projects
关键词
费托合成
Co/Al2O3催化剂
温度还原
高温脱氢
分散性
Fischer-Tropsch synthesis
cobalt/alumina catalyst
temperature programmed reduction
hydrogen temperature programmed desorption