Effects of Zr and K Promoters on Precipitated Iron-Based Catalysts for Fischer–Tropsch Synthesis

• Published in: Catalysis letters Vol. 142; no. 1; pp. 131 - 137
• Main Authors: Zhang, Haojian, Ma, Hongfang, Zhang, Haitao, Ying, Weiyong, Fang, Dingye
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.01.2012; Springer
• Subjects: Adsorption; Catalysis; Catalysts; Chemistry; Chemistry and Materials Science; Exact sciences and technology; General and physical chemistry; Industrial Chemistry/Chemical Engineering; Iron; Organometallic Chemistry; Physical Chemistry; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zirconium; Precipitated iron-based catalyst; Zr promoter; K promoter; Fischer–Tropsch synthesis; Methane; Binary compound; Iron; Moessbauer spectrometry; Physisorption; Silica; Promoter; Chemical reduction; Structure; Catalytic reaction; Hydrocarbon; Fischer Tropsch synthesis; Thermodesorption; Transition metal; Heterogeneous catalysis; Fischer-Tropsch synthesis; Adsorption; Silicon oxides; Distribution; Surface area; Catalyst; Carburization
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-011-0739-3

The effects of Zr and K promoters on the structure, adsorption, reduction, carburization and catalytic behavior of precipitated iron-based Fischer–Tropsch synthesis (FTS) catalysts were investigated. The catalysts were characterized by N 2 physisorption, temperature-programmed reduction/desorption (TPR/TPD) and Mössbauer effect spectroscopy (MES) techniques. As revealed by N 2 physisorption, Zr and/or K promoted catalysts showed lower surface area than Fe/SiO 2 catalyst. Zr promoter inhibited the reduction and carburization because of the interaction between Fe and Zr in Fe–Zr/SiO 2 catalysts. K promoter enhanced the reduction in CO and apparently facilitated the CO adsorption, thus promoted the carburization, but it retarded the reduction in H 2 and severely suppressed the H 2 adsorption. Compared with the singly promoted catalysts, the doubly promoted catalyst had the highest FTS activity. In addition, both Zr and K promoters suppressed the formation of methane and shifted the production distribution to heavy hydrocarbons. Graphical Abstract Both Zr and K restrained the formation of methane, and increased the heavy hydrocarbons selectivity. In the FTS reaction, the doubly promoted catalyst Fe–Zr–K/SiO 2 had the highest FTS activity.