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Title: Adsorption and dissociation of molecular hydrogen on orthorhombic β-Mo 2C and cubic δ-MoC (001) surfaces

Molybdenum carbides are increasingly used in heterogeneously catalyzed hydrogenation reactions, which imply the adsorption and dissociation of molecular hydrogen. In this paper, a systematic density functional theory based study, including or excluding dispersion terms, concerning the interaction and stability of H 2 with cubic δ-MoC(001) and orthorhombic β-Mo 2C(001) surfaces, is presented. In the latter case the two possible C or Mo terminations are considered. In addition, different situations for the H covered surfaces are examined. Computational results including dispersive forces predict an essentially spontaneous dissociation of H 2 on β-Mo 2C(001) independently of the surface termination, whereas on δ-MoC(001) molecular hydrogen dissociation implies a small but noticeable energy barrier. Furthermore, the ab initio thermodynamics formalism has been used to compare the stability of different H coverages. In conclusion, core level binding energies and vibrational frequencies are presented with the aim to assist the interpretation of yet unavailable data from X-ray photoelectron and infrared spectroscopies.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of Barcelona (Spain). Inst. of Theoretical and Computational Chemistry (IQTCUB). Dept. of Physical Chemistry and Materials Science
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Dept.
Publication Date:
Report Number(s):
BNL-113840-2017-JA
Journal ID: ISSN 0039-6028; R&D Project: CO040; KC0302010
Grant/Contract Number:
SC0012704; CTQ2015-64618-R; CTQ2012-30751; RYC-2012-10129; 2014SGR97; XRQTC; 676580
Type:
Accepted Manuscript
Journal Name:
Surface Science
Additional Journal Information:
Journal Volume: 656; Journal ID: ISSN 0039-6028
Publisher:
Elsevier
Research Org:
Univ. of Barcelona (Spain); Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE; Ministry of Economy, Industry and Competitiveness (MINECO) (Spain); Generalitat de Catalunya; European Union (EU); Catalan Institution for Research and Advanced Studies (ICREA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Density functional calculations; Molybdenum carbides; H2 dissociation; Ab initio thermodynamics; IR spectroscopy; Core level shifts
OSTI Identifier:
1358020
Alternate Identifier(s):
OSTI ID: 1397463

Posada-Pérez, Sergio, Viñes, Francesc, Valero, Rosendo, Rodriguez, José A., and Illas, Francesc. Adsorption and dissociation of molecular hydrogen on orthorhombic β-Mo2C and cubic δ-MoC (001) surfaces. United States: N. p., Web. doi:10.1016/j.susc.2016.10.001.
Posada-Pérez, Sergio, Viñes, Francesc, Valero, Rosendo, Rodriguez, José A., & Illas, Francesc. Adsorption and dissociation of molecular hydrogen on orthorhombic β-Mo2C and cubic δ-MoC (001) surfaces. United States. doi:10.1016/j.susc.2016.10.001.
Posada-Pérez, Sergio, Viñes, Francesc, Valero, Rosendo, Rodriguez, José A., and Illas, Francesc. 2016. "Adsorption and dissociation of molecular hydrogen on orthorhombic β-Mo2C and cubic δ-MoC (001) surfaces". United States. doi:10.1016/j.susc.2016.10.001. https://www.osti.gov/servlets/purl/1358020.
@article{osti_1358020,
title = {Adsorption and dissociation of molecular hydrogen on orthorhombic β-Mo2C and cubic δ-MoC (001) surfaces},
author = {Posada-Pérez, Sergio and Viñes, Francesc and Valero, Rosendo and Rodriguez, José A. and Illas, Francesc},
abstractNote = {Molybdenum carbides are increasingly used in heterogeneously catalyzed hydrogenation reactions, which imply the adsorption and dissociation of molecular hydrogen. In this paper, a systematic density functional theory based study, including or excluding dispersion terms, concerning the interaction and stability of H2 with cubic δ-MoC(001) and orthorhombic β-Mo2C(001) surfaces, is presented. In the latter case the two possible C or Mo terminations are considered. In addition, different situations for the H covered surfaces are examined. Computational results including dispersive forces predict an essentially spontaneous dissociation of H2 on β-Mo2C(001) independently of the surface termination, whereas on δ-MoC(001) molecular hydrogen dissociation implies a small but noticeable energy barrier. Furthermore, the ab initio thermodynamics formalism has been used to compare the stability of different H coverages. In conclusion, core level binding energies and vibrational frequencies are presented with the aim to assist the interpretation of yet unavailable data from X-ray photoelectron and infrared spectroscopies.},
doi = {10.1016/j.susc.2016.10.001},
journal = {Surface Science},
number = ,
volume = 656,
place = {United States},
year = {2016},
month = {10}
}