DFT-D3 study of H2 and N2 chemisorption over cobalt promoted Ta3N5 (100), (010) and (001) surfaces

Zeinalipour-Yazdi, C. D., Hargreaves, J. S.J. , Laassiri, S. and Catlow, C. R. A. (2017) DFT-D3 study of H2 and N2 chemisorption over cobalt promoted Ta3N5 (100), (010) and (001) surfaces. Physical Chemistry Chemical Physics, 19(19), pp. 11968-11974. (doi: 10.1039/C7CP00806F) (PMID:28440821)

139810.pdf - Published Version
Available under License Creative Commons Attribution.



The reactants for ammonia synthesis have been studied, employing density functional theory (DFT), with respect to their adsorption on tantalum nitride surfaces. The adsorption of nitrogen was found to be mostly molecular and non-activated with side-on, end-on and tilt configurations. At bridging nitrogen sites (Ta–N–Ta) it results in an azide functional group formation with a formation energy of 205 kJ mol−1. H2 was found also to chemisorb molecularly with an adsorption energy in the range −81 to −91 kJ mol−1. At bridging nitrogen sites it adsorbs dissociatively forming >NH groups with an exothermic formation energy of −175 kJ mol−1 per H2. The nitrogen vacancy formation energies were relatively high compared to other metal nitrides found to be 2.89 eV, 2.32 eV and 1.95 eV for plain, surface co-adsorbed cobalt and sub-surface co-adsorbed cobalt Ta3N5-(010). Co-adsorption of cobalt was found to occur mostly at nitrogen rich sites of the surface with an adsorption energy that ranged between −200 to −400 kJ mol−1. The co-adsorption of cobalt was found to enhance the dissociation of molecular hydrogen on the surface of Ta3N5. The studies offer significant new insight with respect to the chemistry of N2 and H2 with tantalum nitride surfaces in the presence of cobalt promoters.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Laassiri, Dr Said and Hargreaves, Professor Justin
Authors: Zeinalipour-Yazdi, C. D., Hargreaves, J. S.J., Laassiri, S., and Catlow, C. R. A.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Physical Chemistry Chemical Physics
Publisher:Royal Society of Chemistry
ISSN (Online):1463-9084
Published Online:24 April 2017
Copyright Holders:Copyright © 2017 The Owner Societies
First Published:First published in Physical Chemistry Chemical Physics 19(19): 11968-11974
Publisher Policy:Reproduced under a Creative Commons License

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
652781First principles design of novel ammonia synthesis catalystsJustin HargreavesEngineering and Physical Sciences Research Council (EPSRC)EP/L02537X/1CHEM - CHEMISTRY