SiO2 Supported Cobalt-Based Catalyst Prepared By Dielectric-Barrier Discharge Plasma for Fischer-Tropsch Synthesis From Syngas

SiO₂ Supported Cobalt-Based Catalyst Prepared by Dielectric-barrier

Discharge Plasma for Fischer-Tropsch Synthesis from Syngas

Tingjun Fu, Yunhui Jiang, Zhenhua Li

Key Lab for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China

Co/SiO₂ and zirconium promoted Co/Zr/SiO₂ catalysts were prepared by using dielectric-barrier discharge (DBD) plasma instead of conventional thermal calcination method. The Fischer-Tropsch Synthesis (FTS) performance was evaluated in a fixed bed reactor. The results indicated that DBD plasma promotes the FTS activity and heavy hydrocarbon formation compared with the conventional thermal calcination method. The increase of CO conversion was unnoticeable on Co/SiO₂ catalyst prepared by DBD plasma while the increase of CO conversion was significant on the Co/Zr/SiO₂ catalyst prepared by DBD plasma. The heavy hydrocarbon selectivity and the chain growth probability (¦Á value) enhanced on all the catalysts treated by DBD plasma. In order to study the effect of DBD plasma treatment on the FTS performance, the catalyst was characterized by N₂-physisorption, H₂-TPR, H₂-TPD, TEM and XRD. It was proved that DBD plasma not only decreases the precursor decomposition time but also achieves a better cobalt dispersion, smaller Co₃O₄ cluster size and more uniform cobalt distribution. Unfortunately, cobalt reducibility was hindered to some extent in Co/SiO₂ catalyst prepared by DBD plasma while the additive zirconium significantly prevented the decrease of cobalt reducibility and increased cobalt dispersion and the FTS performance.

Keywords: Fischer-Tropsch synthesis; Cobalt; Silica; Zirconium; Plasma