用于气液转化过程应用的纳米级钴基费托合成催化剂。

Nano-sized cobalt based Fischer-Tropsch catalysts for gas-to-liquid process applications.

作者信息

Kang Jung Shik, Awate S V, Lee Yun Ju, Kim So Jung, Park Moon Ju, Lee Sang Deuk, Hong Suk-In, Moon Dong Ju

机构信息

Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, Korea.

出版信息

J Nanosci Nanotechnol. 2010 May;10(5):3700-4. doi: 10.1166/jnn.2010.2339.

DOI:10.1166/jnn.2010.2339

PMID:20359031

Abstract

Nano-sized cobalt supported catalysts were prepared for Fischer-Tropsch synthesis in gas-to-liquid (GTL) process. The dependence of crystallite size and reducibility of Co3O4 on the supports were investigated with FTS activity. XRD peaks revealed nano crystallites (< 5.47 nm) of Co3O4 crystallites. TEM showed round shaped particles with size less than 5 nm. Support with higher acidity decreased crystallite size of Co3O4. XRD data of used catalysts showed Co3O4 crystallites smaller than 3.5 nm which do not reduce easily to Co(0) state. The crystallite size of Co3O4 plays a role in its reduction to Co(0). TPR results showed that the reduction temperature shifts to higher temperature due to metal-support interaction. The variation in the activity of the catalysts depends on the support which in turn affects the crystallite size, dispersion, reducibility and activity of Co species in Fischer-Tropsch Synthesis (FTS). In this study, Co/Al2O3 showed higher CO conversion than the other catalysts. However, the C5+ production was in order Co/SiO2 (78.1%) > Co/Al2O3 (70.0%) > Co/R_TiO2 (61%) > Co/A_TiO2 (57.5%).

摘要

制备了用于气制液（GTL）工艺中费托合成的纳米级钴负载催化剂。研究了Co3O4的微晶尺寸和还原性对载体的依赖性及其与费托合成活性的关系。X射线衍射（XRD）峰显示Co3O4微晶的纳米微晶（<5.47 nm）。透射电子显微镜（TEM）显示尺寸小于5 nm的圆形颗粒。酸性较高的载体降低了Co3O4的微晶尺寸。使用过的催化剂的XRD数据显示，Co3O4微晶小于3.5 nm，不易还原为Co(0)态。Co3O4的微晶尺寸在其还原为Co(0)的过程中起作用。程序升温还原（TPR）结果表明，由于金属-载体相互作用，还原温度向更高温度移动。催化剂活性的变化取决于载体，而载体又反过来影响费托合成（FTS）中Co物种的微晶尺寸、分散性、还原性和活性。在本研究中，Co/Al2O3表现出比其他催化剂更高的CO转化率。然而，C5+产物的生成顺序为Co/SiO2（78.1%）>Co/Al2O3（70.0%）>Co/R_TiO2（61%）>Co/A_TiO2（57.5%）。