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Ni–Fe catalysts derived from hydrotalcite-like precursors for hydrogen production by ethanol steam reforming

Paper ID Volume ID Publish Year Pages File Format Full-Text
40609 45859 2013 14 PDF Available
Title
Ni–Fe catalysts derived from hydrotalcite-like precursors for hydrogen production by ethanol steam reforming
Abstract

Nickel–iron mixed oxides derived from reevesite, a hydrotalcite-type compound, were tested in steam reforming of ethanol for hydrogen production. The influence of iron content (Ni/Fe ranging from 3 to 1) and the calcination temperature of the catalyst precursor (773 and 1073 K) on the catalytic performance were investigated. Both parameters were essential to optimize the reforming performance. Increasing the amount of iron in the reevesite precursors affected both the chemical and activity properties of the derived mixed oxide catalysts. Iron displays a positive role in nickel-based catalysts due to the enhancement of catalytic activity and hydrogen selectivity induced by the improved dispersion of nickel and the alleviation in carbon deposition. The calcination temperature led to variations in phase composition consisting of Ni(Fe)Ox solid solution and NiFe2O4, which affected the final size and dispersion of nickel species formed during the reaction. The best catalyst, with a Ni/Fe ratio of 1 and calcined at 773 K, rendered high and stable hydrogen and carbon dioxide selectivity of up to ca. 60% and 40%, respectively, low methane content, and consisted of a Ni(Fe)Ox + NiFe2O4 mixture with high surface area and small Ni0 crystallites. A higher percentage of crystalline NiFe2O4 attained at high calcination temperature (1073 K) associated with a lower carbon deposition resistance and probably Ni0 sintering brings about lower activity and fast deactivation. The improved performance over catalysts calcined at lower temperature and with lower Ni/Fe ratio is motivated by the effect of iron on the structural and electronic properties of the mixed oxides, thus inducing a slow formation of metallic nickel particles and coke deposits. Features like high surface area, higher iron content, lower reducibility of nickel species and small nickel crystallite size well dispersed on the surface of the catalyst with high iron content lead to a higher activity in ethanol dehydrogenation, acetaldehyde decarbonylation and reforming, and WGS.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (247 K)Download as PowerPoint slideHighlights► Nickel–iron mixed oxides from hydrotalcite were tested in ESR for H2 production. ► Study of the influence of Fe content and calcination temperature. ► Iron improves nickel dispersion and alleviates carbon deposition. ► Higher surface area and small Ni crystallite size at low calcination temperature. ► Higher Fe content and lower calcination temperature induce superior performance.

Keywords
Ethanol steam reforming; Layered double hydroxide; Nickel; Iron; Hydrogen
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Ni–Fe catalysts derived from hydrotalcite-like precursors for hydrogen production by ethanol steam reforming
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 450, 15 January 2013, Pages 261–274
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