(621c) Structure and Catalytic Performance of CoAl2O4-Al2O3 Supported Cobalt Catalyst for Fischer-Tropsch Synthesis

Structure
and Catalytic Performance of CoAl₂O₄-Al₂O₃
Supported Cobalt Catalyst for Fischer-Tropsch Synthesis

Litao Jia^a, Jiankang Han^a,b,Bo Hou^a, Debao Li^a*

^a State Key Laboratory of Coal
Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan,
030001, China.

b University of Chinese Academy
of Sciences, Beijing 100039, China

*Corresponding author: Tel. /Fax: +86
351 4040410. E-mail addresses: dbli@sxicc.ac.cn

The Fischer¨CTropsch
synthesis (FTS) can convert syngas (CO +H2) into clean and renewable
transportation fuels, which has received an increasing interest from academia
and industry. Amongst the reported catalysts, cobalt-based catalysts showed low
activity for the water-gas shift reaction, deactivated less rapidly and yielded
a high fraction of linear parrifin. Alumina as a kind
of traditional support for F-T synthesis catalysts,
has high mechanical strength and good friction resistance. While,
the strong interactions between the alumina and cobalt reduced the reduction
degree of cobalt, which strongly influence the performance of the catalyst.

In the present study, the Al₂O₃
was modified by CoAl₂O₄ microcrystalline through
impregnation method. And then the modified Al₂O₃ acted as
support for cobalt. The as-prepared catalysts were characterized by BET, XRD, H₂-TPR,
XPS and H₂-chemisorption, and applied in Fischer¨CTropsch
synthesis (FTS). The results show that the existence of CoAl₂O₄
on surface of the Al₂O₃ effectively weakened the
interaction between Co and Al₂O₃, thus greatly improve
the reduction of catalysts and catalytic activity. With the increase of CoAl₂O₄
content, the reduction degree and catalytic activity of catalysts increase,
which reach the maximum with 20 wt% CoAl₂O₄
content. The catalytic performance showed that, with the modification CoAl₂O₄,
the CH₄ selectivity was decreased and the C₅₊ selectivity
was enhanced. In addition, CoAl₂O₄ modification also improves
the catalyst stability.

Keywords: Fischer-Tropsch synthesis, cobalt/Alumina catalysts, CoAl₂O₄
modified Al₂O_3,