Reaction mechanism of methanol to formaldehyde over Fe- and FeO-modified graphene.

Abstract

We employed periodic DFT calculations (PBE-D2) to investigate the catalytic conversion of methanol over graphene embedded with Fe and FeO. Two possible pathways of dehydrogenation to formaldehyde and dehydration to dimethyl ether (DME) over these catalysts were examined. Both processes are initiated with the activation of methanol over the catalytic center through O-H cleavage. As a result, a methoxo-containing intermediate is formed. Subsequently, H-transfer from the methoxy to the adjacent ligand leads to the formation of formaldehyde. Conversely, the activation of the second methanol over the intermediate gives DME and H2O. Over Fe/graphene, the dehydration process is kinetically and thermodynamically preferable. Unlike Fe/graphene, FeO/graphene is predicted to be an efficient catalyst for the dehydrogenation process. Oxidative dehydrogenation over FeO/graphene takes place through two steps with free energy barriers of 5.7 and 10.2 kcal mol(-1).

• Authors: Anawat Thivasasith, Jakkapan Sirijaraensre, Pipat Khongpracha, Chompunuch Warakulwit, Bavornpon Jansang, Jumras Limtrakul
• Journal: Chemphyschem : a European journal of chemical physics and physical chemistry (Chemphyschem) Vol. 16 Issue 5 Pg. 986-92 (Apr 07 2015) ISSN: 1439-7641 [Electronic] Germany
• PMID: 25640257 (Publication Type: Journal Article)
• Copyright: © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.