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Effect of pre-treatment on physico-chemical properties and stability of carbon nanotubes supported iron Fischer–Tropsch catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
42711 45938 2009 9 PDF Available
Title
Effect of pre-treatment on physico-chemical properties and stability of carbon nanotubes supported iron Fischer–Tropsch catalysts
Abstract

This paper presents the effects of acid treatment on the activity, product selectivity and life span of iron Fischer–Tropsch (FT) catalysts supported on carbon nanotubes (CNTs). Two different types of CNTs with low surface area (∼25 m2/g) and high surface area (∼170 m2/g) were prepared and treated with 35 wt% HNO3 at 25 °C and 110 °C for 16 h. Fe/CNTs were prepared using incipient wetness impregnation method with iron loading of 10 wt%. The CNT supports and catalysts were characterized by nitrogen adsorption, ICP, TPR, XRD, SEM, TEM and Raman spectroscopy. The acid treatments at 25 °C and 110 °C increased the BET surface area by 18% and 31%. The results of Raman analysis revealed that the acid treatment increased the number of defects which are considered as anchoring site for metal particles. TEM analysis showed that the major parts of the iron particles were homogenously distributed inside the acid treated nanotubes. According to the XRD analysis, the acid treatment on both families of CNTs resulted in decrease in metal particle sizes. The FT synthesis was carried out in a fixed-bed microreactor (275 °C, 2 MPa, CO/H2 = 2) for 120 h. Among the catalysts studied, Fe catalyst supported on pre-treated CNTs at 110 °C was stable and active while, the other catalysts experienced rapid deactivations. The Fe catalyst supported on CNTs low surface area and larger diameter showed much lower CH4 and higher C5+ selectivities.

Graphical abstractThis paper presents the effects of acid treatment on the activity, product selectivity and life span of iron Fischer–Tropsch (FT) catalysts supported on carbon nanotubes (CNTs). Two different types of CNTs with low surface area (∼30 m2/g) and high surface area (∼180 m2/g) were prepared and treated with 35 wt% HNO3 at 25 °C and 110 °C for 16 h. Fe/CNTs were prepared using incipient wetness impregnation method with iron loading of 10 wt%. The CNT supports and catalysts were characterized by nitrogen adsorption, ICP, TPR, XRD, SEM, TEM and Raman spectroscopy. The FT synthesis was carried out in a fixed-bed microreactor (275 °C, 2 MPa, CO/H2 = 2) for 120 h. Among the catalysts studied, Fe catalyst supported on pre-treated CNTs at 110 °C was stable and active while, the other catalysts experienced rapid deactivations. The Fe catalyst supported on CNTs low surface area and larger diameter showed much lower CH4 and higher C5+ selectivities.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Fischer–Tropsch synthesis; Iron catalyst; Carbon nanotubes; Acid treatment; Activity; Stability
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Effect of pre-treatment on physico-chemical properties and stability of carbon nanotubes supported iron Fischer–Tropsch catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 355, Issues 1–2, 28 February 2009, Pages 33–41
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us