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The catalytic de-hydrogenation of phenol molecular by metallic Cu(100), Fe(100) and their oxides surfaces

Ahmed, O.H., Altarawneh, M., Dlugogorski, B.Z. and Jiang, Z-T (2018) The catalytic de-hydrogenation of phenol molecular by metallic Cu(100), Fe(100) and their oxides surfaces. In: Australian Institute of Physics (AIP) WA 2018 Postgraduate Student Conference, 15 November 2018, University of Western Australia, Perth

Abstract

The interplay of aromatic molecules with 3d transition metals, such as Fe and Cu, and their oxide surfaces provide important fingerprints for environmental burdens associated with thermal recycling of e-waste. Previous DRIFTS and EPR measurements established a strong interaction of the phenol molecule with the metal oxides via the formation of phenolic and catecholic intermediates. In this contribution, we comparatively examined the adsorption of phenol molecule, as a representative model for oxygen-containing components on pure metallic surfaces and their partially oxidized surfaces through accurate density functional theory (DFT) studies. In particular, it is the aim of elucidating the specific underlying mechanism of these reactions as well as to unravel the catalytic effect of these different substrates. Simulated results show that, the phenol molecule undergoes partial hydrogenation to generate phenoxy-type adduct mediated by the metallic surfaces. Investigation found that the phenol physisorbed adapts on the pure Cu and Fe surfaces are very weak; with the binding energies of -2.4 and -2.1 kcal/mol compared to -3.1 and -5.5 kcal/mol for their partially oxidized surfaces, respectively. Molecular attributes based on charge transfer and geometrical features provide an insightful explanation into these energetic trends. Furthermore, the thermo-kinetic parameters established over the temperature region of 300 and 1000 K, exhibit a lower activation energy for phenol decomposition into phenoxy group over the oxide surfaces in reference to their pure surfaces (24 and 43 kcal/mol vs 38 and 47 kcal/mol). Clearly, vacancies on pure metallic surfaces substantially reduce the activation energies required in the fission of the phenolic’s O-H bonds.

Publication Type: Conference Paper
Murdoch Affiliation: School of Engineering and Information Technology
Conference Website: http://aip.org.au/activities/wa-postgrad-conferenc...
URI: http://researchrepository.murdoch.edu.au/id/eprint/42619
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