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Effects of Potassium Loading over Iron–Silica Interaction, Phase Evolution and Catalytic Behavior of Precipitated Iron-Based Catalysts for Fischer-Tropsch Synthesis.

Authors :
Chang, Hai
Lin, Quan
Cheng, Meng
Zhang, Kui
Feng, Bo
Chai, Jiachun
Lv, Yijun
Men, Zhuowu
Source :
Catalysts (2073-4344). Aug2022, Vol. 12 Issue 8, p916. 22p.
Publication Year :
2022

Abstract

Potassium (K) promoter and its loading contents were shown to have remarkable effects on the Fe–O–Si interaction of precipitated Fe/Cu/K/SiO2 catalysts for low-temperature Fischer-Tropsch synthesis (FTS). With the increase in K content from 2.3% (100 g Fe based) up to 7% in the calcined precursors, Fe–O–Si interaction was weakened, as reflected by ATR/FTIR, H2-TPR and XPS investigations. XRD results confirmed that the diffraction peak intensity from (510) facet of χ-Fe5C2 phase strengthened with increasing K loading, which indicates the crystallite size of χ-Fe5C2 increased with the increase in K contents either during the syngas reduction/carburization procedure or after FTS reaction. H2-TPH results indicated that more reactive surface carbon (alpha-carbon) was obtained over the higher K samples pre-carburized by syngas. Raman spectra illustrated that a greater proportion of graphitic carbon was accumulated over the surface of spent samples with higher K loading. At the same time, ATR-FTIR, XRD and Mössbauer spectra (MES) characterization results showed that a relatively higher level of bulk phase Fayalite (Fe2SiO4) species was observed discernibly in the lowest K loading sample (2.3 K%) in this work. The catalytic evaluation results showed that the CO conversion, CO2 selectivity and O/P (C2–C4) ratio increased progressively with the increasing K loading, whereas a monotonic decline in both CO conversion and O/P (C2–C4) ratio was observed on the highest K loading sample during c.a. 280 h of TOS. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20734344
Volume :
12
Issue :
8
Database :
Academic Search Index
Journal :
Catalysts (2073-4344)
Publication Type :
Academic Journal
Accession number :
158748778
Full Text :
https://doi.org/10.3390/catal12080916