Interlayer Cation Exchange Stabilizes Polar Perovskite Surfaces

Deacon-Smith, D; Scanlon, David O.; Catlow, C. Richard A.; Sokol, Alexey A.; Woodley, Scott M.

doi:10.1002/adma.201401858

Cited by 42 publications

(39 citation statements)

References 51 publications

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“…While these also require ion migration from the near-surface region, they additionally involve cation exchanges. [33] AD experiments in the FSU HAS laboratory on cleaved, single-crystal KTN targets, in both <10> and <11> high symmetry azimuths, yielded Bragg peaks consistent with the 4 Å surface lattice parameter expected for both KO and TaO 2 /NbO 2 layers. [4][5][6][7] (See Figure 1a.) Hence, the KO surface formed after stabilization appears essentially the same as the KO layer produced by the cleaving.…”

supporting

confidence: 53%

Polar catastrophe and the structure ofKTa1−xNbxO3surfaces: Resu

Flaherty

Trelenberg

et al. 2015

Phys. Rev. B

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supporting

confidence: 53%

Polar catastrophe and the structure ofKTa1−xNbxO3surfaces: Resu

Flaherty

Trelenberg

et al. 2015

Phys. Rev. B

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“…This stress is typically relieved by structural relaxations and, in more complicated cases, atomic rearrangement [3,[22][23][24][25]. Surface relaxation mechanisms have been proposed for ionic systems, with most models describing the relaxation in terms of the electrostatic interactions and short-range repulsion between ions [3,22].…”

Section: Introductionmentioning

confidence: 99%

Structural, energetic and electronic properties of (100) surfaces for alkaline earth metal oxides as calculated with hybrid density functional theory

et al. 2015

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a b s t r a c tWe perform a systematic investigation of (100) surfaces for rocksalt-structured group 2 metal oxides, namely MgO, CaO, SrO and BaO, using GGA and Hybrid-DFT exchange-correlation functionals. We examine the structural, energetic and electronic properties of the surfaces, with a specific focus on the surface ionisation potential and band bending; the latter of which we quantify by examining the density of states as a function of depth from the system surface. We report structural and energetic results in-line with previous experimental work when we use the Hybrid-DFT method, and for the electronic structure we find inequivalent band bending for the valence and conduction bands, which results in reduced ionisation potentials and the closure of the band gap at the surface when compared to bulk systems. We also report downward bending of the conduction band for MgO that brings it below the vacuum potential, unlike previous theoretical investigations, and thus indicates an origin of the positive electron affinity found in the experiment.

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“…Interstitial oxygen ions largely contribute to the conduction of charge carriers via the rapid diffusion mechanism along the apical positions of NiO6 corner sharing octahedra in the perovskite layers. [9][10][11][12][13] In solid oxide fuel and/or electrolyser cells (SOFCs & SOECs), the most important requirement for achieving high conversion efficiencies at low to intermediate operating temperatures is identified as the facile kinetics of electrode reactions. In particular, the oxygen reduction reaction (ORR) is considered a major rate limiting factor for intermediate temperature operation.…”

Section: Introductionmentioning

confidence: 99%

The interaction of molecular oxygen on LaO terminated surfaces of La₂NiO₄

et al. 2016

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Rare-earth metal oxides with perovskite-type crystal structures are under consideration for use as air electrode materials for intermediate to high temperature electrochemical device applications.The surface chemistry of these materials plays a critical role in determining the kinetics of oxygen reduction and exchange reactions. Among various perovskite-structured oxides, certain members of the Ruddlesden-Popper series, e.g. La2NiO4, have been identified as significantly active for surface oxygen interaction. However, the challenge remains to be the identification of the structure and composition of active surfaces, as well as the influence of these factors on the mechanisms of surface exchange reactions. In this contribution, the changes in electronic structure and the energetics of oxygen interaction on surfaces of La2NiO4 are analysed using first principle calculations in the Density Functional Theory (DFT) formalism. As for the surface chemistry, the LaO termination rather than the NiO2 is presumed due to recent experimental evidence for the surfaces of various perovskite structured oxides after heat treatment in oxidizing environments being transition metal free. Our findings substantiate that the LaO terminated surface can indeed participate in the formation of the surface superoxo species. Detailed charge transfer analyses revealed that it is possible for such a surface to be catalytically active owing to the enhanced electronic configurations on neighbouring La sites to surface species. In addition, positively charged oxygen vacancies, relative to the crystal lattice, can act as active sites and catalyse the O-O bond cleavage.

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Interlayer Cation Exchange Stabilizes Polar Perovskite Surfaces

Cited by 42 publications

References 51 publications

Polar catastrophe and the structure ofKTa1−xNbxO3surfaces: Resu

Polar catastrophe and the structure ofKTa1−xNbxO3surfaces: Resu

Structural, energetic and electronic properties of (100) surfaces for alkaline earth metal oxides as calculated with hybrid density functional theory

The interaction of molecular oxygen on LaO terminated surfaces of La₂NiO₄

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Interlayer Cation Exchange Stabilizes Polar Perovskite Surfaces

Cited by 42 publications

References 51 publications

Polar catastrophe and the structure ofKTa1−xNbxO3surfaces: Resu

Polar catastrophe and the structure ofKTa1−xNbxO3surfaces: Resu

Structural, energetic and electronic properties of (100) surfaces for alkaline earth metal oxides as calculated with hybrid density functional theory

The interaction of molecular oxygen on LaO terminated surfaces of La2NiO4

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The interaction of molecular oxygen on LaO terminated surfaces of La₂NiO₄