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Catalytic oxidation of VOCs over mixed Co–Mn oxides

Paper ID Volume ID Publish Year Pages File Format Full-Text
46362 46438 2012 10 PDF Available
Title
Catalytic oxidation of VOCs over mixed Co–Mn oxides
Abstract

This work reports the synthesis and characterization of single-phase cobalt manganese oxide (CMO) spinels Co3−xMnxO4 (0 ≤ x ≤ 0.34) prepared by the pulsed-spray evaporation chemical vapor deposition (PSE–CVD) method. Structure and cationic distribution of the obtained films were characterized by XRD, FTIR, XPS and Raman spectroscopy. Temperature-programmed reduction/re-oxidation (TPR/TPO) was used to elucidate the redox properties of the deposited films. The electrical resistivity was measured in the temperature range of 27–450 °C. XRD, FTIR and Raman spectra reveal the formation of single-phase cubic spinel structures up to x = 0.34. With the substitution of cobalt cations with Mn3+ and Mn4+ ions, the unit cell of the cubic spinel shows a linear increase; the TPR results indicate a lower reducibility while the TPO results display no evident change; also, the ratio Co3+/Co2+ decreased and both electrical resistivity and thermal stability showed increasing trends. The observed behavior is attributed to the progressive incorporation of manganese, which induces structural defects favoring the formation of anionic vacancies and the restriction of the oxygen mobility. The catalytic activities of the doped spinels were investigated for the deep oxidation of unsaturated hydrocarbons (C2H2 and C3H6). The introduction of a slight amount of manganese shifted the light-off curves toward lower temperatures. Based on the XPS results, the enhanced catalytic activity is thought to benefit from the abundant presence of oxygen vacancies in the doped oxide.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Binary spinel-type oxides were synthesized by pulsed spray evaporation (PSE) CVD process. ► The doping effect was evaluated in terms of chemical components and redox properties. ► The solids promote the thermal stability and catalytic activity. ► The Co–Mn oxides suppress the formation of intermediates and favor the selectivity toward CO2 at low temperatures. ► The enhanced catalytic activity benefited from the abundant presence of oxygen vacancies.

Keywords
Catalytic oxidation; Cobalt manganese oxide; Spinel; Pulsed-spray evaporation; Chemical vapor deposition
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 117–118, 18 May 2012, Pages 125–134
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