First-principles modeling of BaCeO_{3}: structure and stabilization of O vacancies by Pd-doping

TL;DR

This study employs first-principles DFT calculations to analyze the structure of BaCeO₃ and Pd-doped variants, revealing how Pd stabilizes oxygen vacancies through redox chemistry and lattice strain relief, aligning with experimental data.

Contribution

It provides detailed atomic-level insights into how Pd doping stabilizes oxygen vacancies in BaCeO₃, a novel understanding supported by computational and experimental correlation.

Findings

Pd doping favors oxygen vacancies adjacent to Pd

Structural analysis confirms oxidation states of Pd

Vacancy stabilization involves redox chemistry and strain relief

Abstract

We use first-principles density functional theory (DFT) calculations to investigate the ground state structures of both BaCeO_{3} (BC) and Pd-doped BC (BCP). The relaxed structures match closely with recent experimental scattering studies, and also provide a local picture of how the BC perovskite lattice accommodates Pd. Both stoichiometric and oxygen-deficient materials are considered, and structures with an O vacancy adjacent to each Pd are predicted to be favored. The oxidation state of Pd in each doped structure is investigated through a structural analysis, the results of which are supported by an orbital-resolved projected density of states. The vacancy stabilization by Pd in BCP is explained through redox chemistry and lattice strain relief.