A CO -Tolerant Perovskite Oxide with High Oxide Ion and Electronic Conductivity.

Mixed ionic-electronic conductors (MIECs) that display high oxide ion conductivity (σ ) and electronic conductivity (σ ) constitute an important family of electrocatalysts for a variety of applications including fuel cells and oxygen separation membranes. Often MIECs exhibit sufficient σ but inadequate σ . It has been a long-standing challenge to develop MIECs with both high σ and stability under device operation conditions.

Electronic properties and surface reactivity of SrO-terminated SrTiO and SrO-terminated iron-doped SrTiO.

Surface reactivity and near-surface electronic properties of SrO-terminated SrTiO and iron doped SrTiO were studied with first principle methods. We have investigated the density of states (DOS) of bulk SrTiO and compared it to DOS of iron-doped SrTiO with different oxidation states of iron corresponding to varying oxygen vacancy content within the bulk material. The obtained bulk DOS was compared to near-surface DOS, i.

Double perovskite cathodes for proton-conducting ceramic fuel cells: are they triple mixed ionic electronic conductors?

O and H diffusion has been investigated at a temperature of 300 °C in the double perovskite material PrBaCoO (PBCO) in flowing air containing 200 mbar of HO. Secondary ion mass spectrometry (SIMS) depth profiling of exchanged ceramics has shown PBCO still retains significant oxygen diffusivity (~1.3 × 10 cms) at this temperature and that the presence of water (HO), gives rise to an enhancement of the surface exchange rate over that in pure oxygen by a factor of ~3.

Oxygen exchange and transport in dual phase ceramic composite electrodes.

Composites consisting of a perovskite-based electronic or mixed conductor with a fluorite-structured ionic conductor are often used as electrodes in solid oxide electrochemical energy conversion devices. After sintering the materials, there is often evidence for inter-reaction between the two phases, or inter-diffusion of cations or impurities between the two phases. We studied the (18)O exchange properties of a composite consisting of CGO and LSCF in a 50 : 50 ratio.

Relating surface chemistry and oxygen surface exchange in LnBaCo2O(5+δ) air electrodes.

The surface and near-surface chemical composition of electroceramic materials often shows significant deviations from that of the bulk. In particular, layered materials, such as cation-ordered LnBaCo2O(5+δ) perovskites (Ln = lanthanide), undergo surface and sub-surface restructuring due to the segregation of the divalent alkaline-earth cation. These processes can take place during synthesis and processing steps (e.

Accurate and precise measurement of oxygen isotopic fractions and diffusion profiles by selective attenuation of secondary ions (SASI).

The accuracy and precision of isotopic analysis in Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) relies on the appropriate reduction of the dead-time and detector saturation effects, especially when analyzing species with high ion yields or present in high concentrations. Conventional approaches to avoid these problems are based on Poisson dead-time correction and/or an overall decrease of the total secondary ion intensity by reducing the target current. This ultimately leads to poor detection limits for the minor isotopes and high uncertainties of the measured isotopic ratios.