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Modification of Co–Mn–Al mixed oxide with potassium and its effect on deep oxidation of VOC

Paper ID Volume ID Publish Year Pages File Format Full-Text
42461 45926 2009 11 PDF Available
Title
Modification of Co–Mn–Al mixed oxide with potassium and its effect on deep oxidation of VOC
Abstract

Catalytic activity of the Co–Mn–Al mixed oxide catalyst (Co:Mn:Al molar ratio of 4:1:1) modified with various amounts of potassium (0–3 wt%) was examined in total oxidation of toluene and ethanol. The prepared catalysts were characterized by chemical analysis (AAS), powder X-ray diffraction (XRD), surface area measurements, temperature programmed techniques (TPR, TPD), voltammetry of microparticles, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The non-modified catalyst was composed of spinel-like Co–Mn–Al mixed oxide as the only XRD crystalline phase. The surface concentrations of metal components obtained by XPS were different from the bulk ones determined by chemical analysis and the segregation of the metal components depended on the actual potassium content. The low K additions changed mainly the surface acid–base properties of the catalyst. According to XRD and voltammetry measurements, Mn oxides segregated from the original spinel-like phase at high concentration of potassium (2.7 and 3.0 wt%); XPS showed an enrichment of the catalysts surface with Mn. The K addition caused significant changes in the catalyst efficiency. The highest conversion in toluene oxidation was achieved with the catalyst containing about 1 wt% K; no reaction by-products were observed beside H2O and CO2. In ethanol oxidation, the catalysts activity gradually increased with increasing potassium content up to about 3 wt% K, but the presence of excess potassium in the Co–Mn–Al catalyst negatively affected formation of reaction by-products: acetaldehyde production steeply increased with potassium concentration higher than 1 wt%.

Graphical abstractCatalytic activity of the Co4MnAl mixed oxide catalyst modified with various amounts of potassium was examined in total oxidation of toluene and ethanol. The highest activity in toluene oxidation was achieved with the catalyst containing ca. 1 wt% K, while in ethanol oxidation the catalysts activity gradually increased with increasing potassium content up to 3 wt% K.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Layered double hydroxides; Mixed oxide catalysts; VOC; Potassium promoter
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Modification of Co–Mn–Al mixed oxide with potassium and its effect on deep oxidation of VOC
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 361, Issues 1–2, 20 June 2009, Pages 106–116
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