The electronic structure of oxygen vacancy defects at the low index surfaces of ceria

Nolan, Michael; Parker, Stephen C.; Watson, Graeme W.

doi:10.1016/j.susc.2005.08.015

Cited by 741 publications

(797 citation statements)

References 24 publications

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“…Ce 3? transformation of two Ce atoms on CeO 2 (110) [15]. However, no metastable CO 2 configuration was found for CO on CeO 2 (110) and CO takes strong adsorption at the Obridge site as reported before.…”

Section: Resultssupporting

confidence: 60%

“…, the CO 2,ad group is somewhat ''pushed'' outward for the accommodation of It was believed that CeO 2 (110) surface is possibly more active than the CeO 2 (111) surface. In recent calculations [15,31], it was found that O-vacancy may form more easily on the (110) surface than (111) surface of ceria and the departure of a neutral O atom leads to Ce 4? ?…”

Section: Resultsmentioning

confidence: 99%

“…To appropriately describe the on-site Coulomb repulsion among Ce 4f electrons, we introduced a Hubbard parameter, U, according to the GGA ? U scheme [14][15][16][17]. The value of U was chosen to be 5 eV, for the best fitting against experimental results of the bulk CeO 2 and CeO 2 -x [15,16].…”

Section: Methodology and Computational Detailsmentioning

confidence: 99%

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Direct CO Oxidation by Lattice Oxygen on Zr-Doped Ceria Surfaces

Yang

Zhang

et al. 2010

Catal Lett

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Systematic density-functional calculations have been performed to address an important issue for CO oxidation on redox ceria: the role of lattice oxygen. One major findings is that CO easily grasps one lattice oxygen atom to form CO 2 -and CO 2 on CeO 2 (111) and Ce 0.75 Zr 0.25 O 2 (111) with small activation energies. Zr dopants facilitate the reduction of Ce ?4 to Ce ?3 and hence weaken the Ce-O bonds, which benefit the direct formation and release of CO 2 .

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Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

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Direct CO Oxidation by Lattice Oxygen on Zr-Doped Ceria Surfaces

Yang

Zhang

et al. 2010

Catal Lett

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“…8 It has subsequently been used to accurately describe pure, defective and doped CeO 2 systems. 31,[38][39][40][41][42][43][44][45][46][47][48][49][50] Furthermore, recent work by Keating et al has shown the additional need to apply a U of 5.5 eV to the 2p states of oxygen when modelling p-type defects in CeO 2 , due to the formation of O hole states. 31 The U value for the oxygen atoms was derived using an ab initio fitting procedure with a Koopman'slike approach.…”

Section: Methodsmentioning

confidence: 99%

Occupation matrix control of d- and f-electron localisations using DFT + U

Allen

Watson

2014

Phys. Chem. Chem. Phys.

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201

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The use of a density functional theory methodology with on-site corrections (DFT + U) has been repeatedly shown to give an improved description of localised d and f states over those predicted with a standard DFT approach. However, the localisation of electrons also carries with it the problem of metastability, due to the possible occupation of different orbitals and different locations. This study details the use of an occupation matrix control methodology for simulating localised d and f states with a plane-wave DFT + U approach which allows the user to control both the site and orbital localisation.This approach is tested for orbital occupation using octahedral and tetrahedral Ti(III) and Ce(III) carbonyl clusters and for orbital and site location using the periodic systems anatase-TiO 2 and CeO 2 . The periodic cells are tested by the addition of an electron and through the formation of a neutral oxygen vacancy (leaving two electrons to localise). These test systems allow the successful study of orbital degeneracies, the presence of metastable states and the importance of controlling the site of localisation within the cell, and it highlights the use an occupation matrix control methodology can have in electronic structure calculations.

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“…The spin density is defined as the difference in the electron density of up and down electron spin densities. 29,30 Additionally the cohesive energy (E coh ) of each model system was calculated. It is defined as the energy required for breaking the system into the isolated atomic species.…”

Section: Methods and Calculationsmentioning

confidence: 99%

Effects of N doping on the electronic properties of a small carbon atomic chain with distinctsp2terminations: A first-principles study

et al. 2011

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Carbon nanostructures consisting of corannulene/coronene-like pieces connected by atomic chains and doped with nitrogen atoms have been addressed by carrying out first-principles calculations within the framework of the spin-polarized density functional theory. Our results show that the conformation, charge distributions, and spin states are significantly influenced by the nitrogen incorporation in comparison to these characteristics of similar pure carbon structures. Higher concentration of incorporated nitrogen leads to a smaller highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap and different conductive states near the Fermi level. In turn the different location of the N-incorporation sites allows switching on and off of the π -electron magnetism in these systems. We found that the rotational deformation of the terminations with respect to the carbon chain depends on the number and the location of the incorporated N atoms. The most stable N-doped structures exhibit a relative rotation of the terminations of approximately 90 degrees. These findings indicate that by controllable N doping one can tune the conducting channel of carbon chains connected to sp 2 terminations; thus obtaining low band-gap nano-units.

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The electronic structure of oxygen vacancy defects at the low index surfaces of ceria

Cited by 741 publications

References 24 publications

Direct CO Oxidation by Lattice Oxygen on Zr-Doped Ceria Surfaces

Direct CO Oxidation by Lattice Oxygen on Zr-Doped Ceria Surfaces

Occupation matrix control of d- and f-electron localisations using DFT + U

Effects of N doping on the electronic properties of a small carbon atomic chain with distinctsp2terminations: A first-principles study

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