CAJ | 학술논문

以三种不同孔径的SiO2为载体，等体积浸渍法制得三种Co/SiO2催化剂用于费托合成反应，采用氮气物理吸附、H2-TPR、H2-TPD、XRD、SEM和TEM等手段对催化剂的微观结构进行了表征。结果表明，载体的孔径对催化剂中钴的分散度和还原度有显著影响。小孔径SiO2为载体时，钴颗粒多堆积在孔外部，不利于钴颗粒的分散，还原度低；大孔径SiO2为载体时，钴颗粒粒径较大，致使钴分散度降低；两者均不利于CO的转化。而孔径适中的B型SiO2为载体制备的催化剂有较高的钴还原度和分散度，具有较高的费托反应活性和链增长能力。以孔径适中的SiO2为载体，进一步考察了助剂La、Ce和Zr对催化剂微观结构及催化性能的影响。结果表明，三种助剂的加入均改变了SiO2表面的性质，C5+选择性均有所提高，其中以锆为助剂效果最佳。研究表明钴锆界面的生成促进了钴颗粒的分散，提高了催化剂的活性，且有利于重质烃的生成。
이삼충불동공경적SiO2위재체，등체적침지법제득삼충Co/SiO2최화제용우비탁합성반응，채용담기물리흡부、H2-TPR、H2-TPD、XRD、SEM화TEM등수단대최화제적미관결구진행료표정。결과표명，재체적공경대최화제중고적분산도화환원도유현저영향。소공경SiO2위재체시，고과립다퇴적재공외부，불리우고과립적분산，환원도저；대공경SiO2위재체시，고과립립경교대，치사고분산도강저；량자균불리우CO적전화。이공경괄중적B형SiO2위재체제비적최화제유교고적고환원도화분산도，구유교고적비탁반응활성화련증장능력。이공경괄중적SiO2위재체，진일보고찰료조제La、Ce화Zr대최화제미관결구급최화성능적영향。결과표명，삼충조제적가입균개변료SiO2표면적성질，C5+선택성균유소제고，기중이고위조제효과최가。연구표명고고계면적생성촉진료고과립적분산，제고료최화제적활성，차유리우중질경적생성。
Co/SiO2 catalysts supported by three kinds of silica with different pore sizes were prepared using an incipient wetness impregnation method and their performances in the Fischer-Tropsch synthesis were tested. These catalysts were characterized by N2-physisorption, H2-TPR, H2-TPD, XRD, SEM and TEM. The results show that the SiO2 pore size have a significant influence on cobalt dispersion and reducibility. When SiO2 have smaller pore size, most cobalt species are accumulated on the outer surface of the support to form large clusters that leads to a poor cobalt dispersion and lower cobalt reducibility. While for SiO2 with the largest pore size, larger Co3O4 crystallites are formed, which also results in poor cobalt dispersion. Both these two Co/SiO2 catalysts displayed lower Fischer-Tropsch activity. However, the Co/SiO2B catalyst with medium support pore size exhibits better cobalt dispersion and reducibility, which results in an enhanced Fischer-Tropsch activity and hydrocarbon chain growth ability. Furthermore, the effect of additives like lanthanum, zirconium and ceria on the structure and properties of Co/SiO2B catalyst was studied. The results show that these additives can modify the silica surface property and increase the selectivity of C5+. The results show that zirconium is the best additive tested, and the cobalt-zirconium interface can increase the cobalt dispersion, Fischer-Tropsch activity and hydrocarbon chain growth ability.