摘要
考察了Co/SiO2,Co/Ru/SiO2和疏水改性Co/Ru/SiO2催化剂在费-托合成过程中的稳定性.结果发现,随着反应的进行,三种催化剂都呈现一定程度的失活,它们稳定性高低顺序为:疏水改性Co/Ru/SiO2>Co/SiO2>Co/Ru/SiO2.Co/SiO2催化剂的失活是由于催化剂上Co晶粒的长大和硅酸钴物种的生成,而Co/Ru/SiO2和疏水改性Co/Ru/SiO2的失活则是由于催化剂上Co晶粒的长大所致.由于Co/Ru/SiO2催化剂的Co晶粒比Co/SiO2催化剂的小得多,在反应过程中更容易长大,所以Co/Ru/SiO2催化剂稳定性更差;而疏水改性Co/Ru/SiO2催化剂表面的疏水性既抑制了硅酸钴物种的形成,又使Co晶粒长大较慢,因此其稳定性最高.
Stability tests of Co/SiO2,Co/Ru/SiO2,and hydrophobically-organically modified Co/Ru/SiO2 （Co/Ru/SiO2-S） for Fischer-Tropsch synthesis were carried out. As the time on stream went on,CO conversion decreased in all the cases. The growth of cobalt crystallite and the formation of cobalt silicates species were the reasons for Co/SiO2 deactivation,while the deactivation of Co/Ru/SiO2 and Co/Ru/SiO2-S was only attributed to the growth of cobalt crystallite. The stability of the catalysts was in order of Co/Ru/SiO2-S Co/SiO2 Co/Ru/SiO2. Compared with Co/SiO2,the faster deactivation rate for Co/Ru/SiO2 was ascribed to the agglomeration of smaller metal clusters,which were more unstable than the larger metal clusters and therefore more susceptible to sintering processes. Co/Ru/SiO2-S showed the best stability because of no formation of cobalt silicates species and the slow growth of cobalt crystallite.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2010年第12期1483-1488,共6页
基金
国家重点基础研究发展计划(973计划,2005CB221402)
关键词
钴
钌
费-托合成
疏水改性
失活
cobalt
ruthenium
Fischer-Tropsch synthesis
hydrophobically-organic modification
deactivation
