浸渍溶液pH值对Co/SBA-15催化剂F-T合成反应催化性能的影响  

EFFECT OF pH VALUE OF IMPREGNATION SOLUTION ON THE CATALYTIC PERFORMANCE OF Co/SBA-15 FOR FISCHER-TROPSCH SYNTHESIS

作　　者：穆仕芳[1,2] 李德宝[1] 侯博[1] 陈建刚[1] 孙予罕[1] 

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001 [2]中国科学院研究生院,北京100039

出　　处：《石油学报（石油加工）》2009年第A02期5-8,共4页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家重点基础研究发展规划"973"项目(2005CB221402)资助

摘　　要：以SBA-15分子筛为载体,利用硝酸和氨水调节浸渍液的pH值,采用等体积浸渍法制得Co/SBA-15催化剂,结合XRD、TPR和XPS等表征手段,考察了浸渍溶液pH值对催化剂物化性质和催化性能的影响。结果表明,浸渍溶液pH值大于SBA-15的等电点时有利于活性组分Co在载体表面的分散,促进了Co与载体之间的相互作用,降低了Co物种的还原度,使催化活性降低,甲烷选择性增大;浸渍溶液pH值小于载体的等电点时削弱了Co与载体之间的相互作用,提高了Co物种的还原度,进而提高催化剂对F-T合成反应的催化活性和C5+选择性。Co/SBA-15 catalysts were prepared by solution of cobalt nitrate precursor. Nitric acid or nitrate solution, during impregnation, to regulate incipient wetness impregnation of an aqueous ammonium hydroxide was added to the cobalt pH value. The physico-chemical properties of the synthesized samples were characterized by XRD, TPR and XPS. The results showed that the dispersion of Co3O4 species in Co/SBA-15 increased and their reduction degree decreased with the increase of pH, hence, its catalytic activity for F-T synthesis decreased. It is suggested that the SBA-15 surface was negatively charged when the pH of impregnation solution was above the isoelectric point of SBA-15. In this case, the interaction between Co and SBA-15 was promoted, thus the catalytic activity of Co/SBA-15 decreased. On the contrary, when samples were prepared at pH below the isoeleetric point of SBA-15, the interaction between Co and SBA-15 was weakened, the catalytic activity of Co/SBA-15 increased and CH4 selectivity decreased.

关 键 词：PH值 浸渍溶液 Co/SBA-15催化剂 费托合成 

分 类 号：TQ426.85[化学工程]