Dataset Information

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO₃ Perovskites.

ABSTRACT: Polarization of ionic and electronic defects in response to high electric fields plays an essential role in determining properties of materials in applications such as memristive devices. However, isolating the polarization response of individual defects has been challenging for both models and measurements. Here the authors quantify the nonlinear dielectric response of neutral oxygen vacancies, comprised of strongly localized electrons at an oxygen vacancy site, in perovskite oxides of the form ABO₃ . Their approach implements a computationally efficient local Hubbard U correction in density functional theory simulations. These calculations indicate that the electric dipole moment of this defect is correlated positively with the lattice volume, which they varied by elastic strain and by A-site cation species. In addition, the dipole of the neutral oxygen vacancy under electric field increases with increasing reducibility of the B-site cation. The predicted relationship among point defect polarization, mechanical strain, and transition metal chemistry provides insights for the properties of memristive materials and devices under high electric fields.

SUBMITTER: Chi YT

PROVIDER: S-EPMC8811848 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO<sub>3</sub> Perovskites.

Chi Yen-Ting YT Van Vliet Krystyn J KJ Youssef Mostafa M Yildiz Bilge B

Advanced science (Weinheim, Baden-Wurttemberg, Germany) 20211210 4

Polarization of ionic and electronic defects in response to high electric fields plays an essential role in determining properties of materials in applications such as memristive devices. However, isolating the polarization response of individual defects has been challenging for both models and measurements. Here the authors quantify the nonlinear dielectric response of neutral oxygen vacancies, comprised of strongly localized electrons at an oxygen vacancy site, in perovskite oxides of the form ...[more]

PMID: 34894095

Similar Datasets

Project description:Photo- and electrocatalytic technologies hold great promise for activating inert chemical bonds under mild conditions, but rationally selecting a more suitable method in between to maximize the performance remains an open issue, which requires a fundamental understanding of their different catalytic mechanisms. Herein, by first-principles calculations, we systematically compare the activation mechanisms for the C-H bond of the CH4 molecule on TiO2(110) under the photo- and electrocatalytic modes without or with water involved. It quantitatively reveals that the activation barrier of the C-H bond decreases dramatically with a surprising 74% scale by photoexcitation relative to that in thermocatalysis (1.12 eV), while the barrier varies with a maximum promotion of only 5% even under -1 V/Å external electric field (EEF). By detailed geometric/electronic analysis, the superior photocatalytic activity is traced to the highly oxidative lattice Obr •- radical excited by a photohole (h +), which motivates the homolytic C-H bond scission. However, under EEF from -1 V/Å to 1 V/Å, it gives a relatively mild charge polarization on the TiO2(110) surface region and thus a limited promotion for breaking the weakly polar C-H bond. By contrast, in the presence of water, we find that EEF can facilitate CH4 activation indirectly assisted by the surface radical-like OH* species from the oxidative water cleavage at high oxidative potential (>1.85 V vs SHE), which explains the high energy cost to drive electrocatalytic CH4 conversion in experiment. Alternatively, we demonstrate that more efficient CH4 activation could be also achieved at much lower oxidative potential when integrating the light irradiation. In such a circumstance, EEF can not only promote the h + accumulation at the catalyst surface but also help H2O deprotonation to form hydroxide, which can serve as an efficient hole-trapper to generate OH• radical (OH- + h + → OH•), unveiling an interesting synergistic photoelectrocatalytic effect. This work could provide a fundamental insight into the different characteristics of photo- and electrocatalysis in modulating chemical bond cleavage.

Dataset Information

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO₃ Perovskites.

Publications

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO<sub>3</sub> Perovskites.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO3 Perovskites.

Publications

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO<sub>3</sub> Perovskites.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Complex Oxides under Simulated Electric Field: Determinants of Defect Polarization in ABO₃ Perovskites.