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

Brookes, C., Bowker, M., Gibson, E. K. , Gianolio, D., Mohammed, K. M. H., Parry, S., Rogers, S. M., Silverwood, I. P. and Wells, P. P. (2016) In situ spectroscopic investigations of MoOx/Fe2O3 catalysts for the selective oxidation of methanol. Catalysis Science and Technology, 6(3), pp. 722-730. (doi: 10.1039/C5CY01175B)

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.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gibson, Dr Emma
• Authors: Brookes, C., Bowker, M., Gibson, E. K., Gianolio, D., Mohammed, K. M. H., Parry, S., Rogers, S. M., Silverwood, I. P., and Wells, P. P.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Catalysis Science and Technology
• Publisher: Royal Society of Chemistry
• ISSN: 2044-4753
• ISSN (Online): 2044-4761
• Published Online: 24 August 2015
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in Catalysis Science and Technology 6(3):722-730
• Publisher Policy: Reproduced under a Creative Commons License