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Improvement in the coating homogeneity in electrosynthesized Rh structured catalysts for the partial oxidation of methane

Paper ID Volume ID Publish Year Pages File Format Full-Text
54226 47001 2015 11 PDF Available
Title
Improvement in the coating homogeneity in electrosynthesized Rh structured catalysts for the partial oxidation of methane
Abstract

•More homogeneous coating of FeCrAlloy foams with the 3 contact point configuration.•Similar synthesis conditions are achieved, sequential precipitation is not avoided.•Catalytic activity improves when a well-adhered film is synthesized.•Pt plates are homogeneously coated, a similar precipitation than in foams occurs.

The precipitation of Rh/Mg/Al and Rh/Al hydroxides on the surface of FeCrAlloy foams by a base electrogeneration method was investigated to improve the properties of the deposited film (homogeneity and composition) and therefore the performances of the structured catalysts, obtained by calcination, in the Catalytic Partial Oxidation of CH4 to syngas. The work focussed on decreasing current gradients within open-cell foam cylinders by increasing the number of electrical contacts from 1 to 3 points to promote a more homogeneous precipitation of the hydroxides. Electrochemical and catalytic tests as well as SEM/EDS and μ-XRF/XRD analyses allowed to correlate the effect of the number of electrical contact points with materials properties. Lastly, syntheses were performed on Pt plates to study the effect of the electrical behaviour and shape of the support on the composition of the film.A more homogeneous coating of the foam surface was achieved by adopting a configuration with 3 contact points since the reduction of nitrates and water molecules that generates the basic media in the vicinity of the support was enhanced. Layer thicknesses up to 5–15 μm were deposited; however, the sequential precipitation of a film with composition closer to the expected one and a layer enriched in Al and Rh (outer layer) was not avoided. The improvement in the coating gave rise to enhanced performances for a sample prepared at −1.1 V for 3000 s. Contrarily, the low adherence of the outer layer in a sample prepared at −1.2 V for 2000 s during both calcination and catalytic tests may be responsible of the unexpected decrease in catalytic performances. The same sequential precipitation was observed by performing the syntheses on Pt plates, showing that the electrical nature the support did not play a key role on this phenomenon.

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Keywords
Electrosynthesis; Hydrotalcite; Rh; FeCrAlloy foam; Platinum; Catalytic partial oxidation of methane
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Improvement in the coating homogeneity in electrosynthesized Rh structured catalysts for the partial oxidation of methane
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 246, 15 May 2015, Pages 154–164
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