Issue 3, 2016

In situ spectroscopic investigations of MoOx/Fe2O3 catalysts for the selective oxidation of methanol

Abstract

Multicomponent oxide shell@core catalysts have been prepared, affording overlayers of MoOx on Fe2O3. This design approach allows bulk characterization techniques, such as X-ray Absorption Fine Structure (XAFS), to provide surface sensitive information. Coupling this approach with in situ methodologies provides insights during crucial catalytic processes. Calcination studies were followed by a combination of XAFS and Raman, and demonstrate that amorphous multi-layers of MoOx are first converted to MoO3 before formation of Fe2(MoO4)3. However, a single overlayer of Oh Mo units remains at the surface at all times. In situ catalysis studies during formaldehyde production identified that Mo6+ was present throughout, confirming that gas phase oxygen transfer to molybdenum is rapid under reaction conditions. Reduction studies in the presence of MeOH resulted in the formation of reduced Mo–Mo clusters with a bonding distance of 2.6 Å. It is proposed that the presence of the clusters indicates that the selective conversion of MeOH to formaldehyde requires multiple Mo sites.

Graphical abstract: In situ spectroscopic investigations of MoOx/Fe2O3 catalysts for the selective oxidation of methanol

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Article information

Article type
Paper
Submitted
24 Jul 2015
Accepted
21 Aug 2015
First published
24 Aug 2015
This article is Open Access
Creative Commons BY license

Catal. Sci. Technol., 2016,6, 722-730

In situ spectroscopic investigations of MoOx/Fe2O3 catalysts for the selective oxidation of methanol

C. Brookes, M. Bowker, E. K. Gibson, D. Gianolio, K. M. H. Mohammed, S. Parry, S. M. Rogers, I. P. Silverwood and P. P. Wells, Catal. Sci. Technol., 2016, 6, 722 DOI: 10.1039/C5CY01175B

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