title: A DFT+U investigation of hydrogen adsorption on the LaFeO3(010) surface.
abstract: The ABO3perovskite lanthanum ferrite (LaFeO3) is a technologically important electrode material for nickel-metal hydride batteries, energy storage and catalysis. However, the electrochemical hydrogen adsorption mechanism on LaFeO3surfaces remains under debate. In the present study, we have employed spin-polarized density functional theory calculations, with the Hubbard U correction (DFT+U), to unravel the adsorption mechanism of H2on the LaFeO3(010) surface. We show from our calculated adsorption energies that the preferred site for H2adsorption is the Fe-O bridge site, with an adsorption energy of -1.18 eV (including the zero point energy), which resulted in the formation of FeOH and FeH surface species. H2adsorption at the surface oxygen resulted in the formation of a water molecule, which leaves the surface to create an oxygen vacancy. The H2molecule is found to interact weakly with the Fe and La sites, where it is only physisorbed. The electronic structures of the surface-adsorption systems are discussed via projected density of state and Löwdin population analyses. The implications of the calculated adsorption strengths and structures are discussed in terms of the improved design of nickel-metal hydride (Ni-MH) battery prototypes based on LaFeO3.
authors.affiliation: Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. richtiagh@yahoo.com richardtia.cos@knust.edu.gh.
authors.forename: Isaac W
authors.initials: IW
authors.lastname: Boateng
authors.affiliation: Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. richtiagh@yahoo.com richardtia.cos@knust.edu.gh.
authors.forename: Richard
authors.identifier: http://orcid.org/0000-0003-1043-8869
authors.initials: R
authors.lastname: Tia
authors.affiliation: Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. richtiagh@yahoo.com richardtia.cos@knust.edu.gh.
authors.forename: Evans
authors.initials: E
authors.lastname: Adei
authors.affiliation: Department of Earth Sciences, Utrecht University, Princetonplein 9, 3584 CC, Utrecht, The Netherlands.
authors.forename: Nelson Y
authors.initials: NY
authors.lastname: Dzade
authors.affiliation: Department of Chemistry, University College London, 20 Gordon Street, WC1H 0AJ, UK and School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK.
authors.forename: C Richard A
authors.initials: CR
authors.lastname: Catlow
authors.affiliation: Department of Earth Sciences, Utrecht University, Princetonplein 9, 3584 CC, Utrecht, The Netherlands and Department of Chemistry, University College London, 20 Gordon Street, WC1H 0AJ, UK and School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK.
authors.forename: Nora H
authors.initials: NH
authors.lastname: de Leeuw