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Y:BaZrO 3 Perovskite Compounds I: DFT Study on the Unprotonated and Protonated Local Structures
Author(s) -
Cammarata Antonio,
Ordejón Pablo,
Emanuele Antonio,
Duca Dario
Publication year - 2012
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201100974
Subject(s) - yttrium , protonation , proton , octahedron , crystallography , oxygen , zirconium , density functional theory , binding energy , chemistry , perovskite (structure) , vacancy defect , doping , oxide , materials science , inorganic chemistry , crystal structure , computational chemistry , atomic physics , physics , ion , optoelectronics , organic chemistry , quantum mechanics
Y‐doped BaZrO 3 derivatives were studied by density functional theory (DFT) to investigate the local arrangements of the octahedral sites in Pm ${\bar 3}$ m cubic frameworks. Single‐ and double substitution of zirconium by yttrium were considered, including in the presence of a nearby oxygen vacancy. Although the structural symmetry of undoped barium zirconate was not modified after yttrium doping, the presence of yttrium induced several differences in the oxygen sites around it, according to the local geometrical arrangement of yttrium in the host matrix. As an example, the differences between such oxygen sites were shown in the presence of a proton. In this case, different stabilization energies characterized the protonated fragments. Only in those structures, in which two yttrium atoms were neighbors (i.e., formed Y‐O‐Y moieties), were the relative energy differences between the corresponding proton stable sites in agreement with the order of magnitude of the experimental proton‐hopping activation energies. The distribution of such energy differences suggested a grouping of the oxygen atoms into three sets, which had peculiar structural features that weren′t easily deducible from their topologies. The existence of proton traps was also discussed on the basis of the energy‐difference distributions.