Analysis of H2O-induced surface degradation in SrCoO3-derivatives and its impact on redox kinetics
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Substituted SrCoO3 perovskites have been proposed as promising mixed ionic electronic conductors for a range of applications including intermediate temperature solid oxide fuel cells (IT-SOFCs), electrolysers and thermochemical water splitting reactors for H2 production. In this work we investigate the effect of sample exposure to water in substituted SrCoO3 powders and thin films and correlate it with the degradation of oxygen mobility and kinetics. SrCo0.95Sb0.05O3−δ (SCS) thin films have been deposited on different single crystal substrates by pulsed laser deposition (PLD). After water cleaning and post annealing at 300 °C, the sample surface presented an increase of the SrO-surface species as observed by ex situ X-ray Photoemission Spectroscopy (XPS) analysis. This increase in SrO at the sample surface has also been confirmed by the Low Energy Ion Scattering (LEIS) technique on both SCS thin film and powder. Thermochemical water splitting experiments on SCS and SrCo0.95Mo0.05O3−δ (SCM) powder revealed a phase degradation under water oxidising conditions at high temperature with the formation of the trigonal phase Sr6Co5O15. Transmission Electron Microscopy (TEM) analysis of SCS powder treated with water suggests that this phase degradation could already superficially start at Room Temperature (RT). By isotope exchange depth profile experiments on SCS thin films, we were able to quantify the oxygen diffusivity in this SCS surface decomposed layer (D* = 5.1 × 10−17 cm2 s−1 at 400 °C). In the specific case of bulk powder, the effect of water superficial decomposition translates into a lower oxidation and reduction kinetics as demonstrated by comparative thermogravimetric analysis (TGA) studies.
Date Issued
2021-10-07
Date Acceptance
2021-09-30
Citation
Journal of Materials Chemistry A, 2021, 9 (43), pp.24528-24538
ISSN
2050-7488
Publisher
Royal Society of Chemistry
Start Page
24528
End Page
24538
Journal / Book Title
Journal of Materials Chemistry A
Volume
9
Issue
43
Copyright Statement
© The Royal Society of Chemistry 2021. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Identifier
https://pubs.rsc.org/en/content/articlelanding/2021/TA/D1TA04174F
Grant Number
EP/P026478/1
EP/R002010/1
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Energy & Fuels
Materials Science, Multidisciplinary
Chemistry
Materials Science
X-RAY PHOTOELECTRON
PEROVSKITE OXIDES
ELECTRICAL-PROPERTIES
TRANSPORT-PROPERTIES
OXYGEN PERMEABILITY
CATION SEGREGATION
PHASE-TRANSITIONS
CATHODE MATERIAL
THIN-FILMS
STABILITY
0303 Macromolecular and Materials Chemistry
0912 Materials Engineering
0915 Interdisciplinary Engineering
Publication Status
Published
Date Publish Online
2021-10-07