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On the performance of porous silica supported VOx catalysts in the partial oxidation of methane

Paper ID Volume ID Publish Year Pages File Format Full-Text
55150 47042 2012 8 PDF Available
Title
On the performance of porous silica supported VOx catalysts in the partial oxidation of methane
Abstract

In the present study, various VOx containing catalysts were prepared using nanoporous glass and mesoporous silicas (e.g. MCM-41 and SBA-15) as supports. The solids were characterised and tested towards partial oxidation of methane to oxygenates at 923 K. The catalysts were synthesised using two different methods such as (i) wet impregnation (WI) and (ii) incipient wetness impregnation (IWI). BET-surface areas depend on the nature of the support and the type of method of preparation. UV–vis spectra clearly disclose the formation of mainly monomeric VOx species in the samples prepared through IWI. Pyr-FTIR reveals that all the catalysts irrespective of the method of preparation contain both Brønsted and Lewis sites. However, the distribution of these sites again depends on the method of preparation. TEM analysis indicates that the catalysts prepared through IWI provide high dispersion of molecular VOx species on the surface of the support compared to WI. Thus, the catalytic activity and selectivity were also found to depend strongly on the method of preparation. Among the two preparation methods, the catalysts synthesised through IWI revealed higher selectivity and higher space-time-yields to formaldehyde. VOx supported on SBA-15 exhibits superior performance compared to MCM-41. Nanoporous glass supported VOx only show poor performance.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (64 K)Download as PowerPoint slideHighlights► VOx catalysts were prepared using nanoporous glass and mesoporous silicas as supports. ► Two different synthesis routes such as (i) wet impregnation (WI) and (ii) incipient wetness impregnation (IWI) were used. ► Higher selectivities and higher space time yields of formaldehyde were observed by samples prepared by IWI synthesis. ► Catalysts prepared through IWI provide a significantly higher dispersion of molecular VOx species on the surface of the support.

Keywords
Methanol; Formaldehyde; VOx catalysts; Mesoporous silica; SBA-15; MCM-41; Nanoporous glass
First Page Preview
On the performance of porous silica supported VOx catalysts in the partial oxidation of methane
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 192, Issue 1, 30 September 2012, Pages 20–27
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis