Issue 3, 2015

Chromium deposition and poisoning at La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrodes of solid oxide electrolysis cells

Abstract

The degradation of solid oxide electrolysis cells (SOECs) is an issue of both scientific and technical importance. In this study, chromium deposition and poisoning at the La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) anode or the oxygen electrode of SOECs are studied for the first time under a current density of 200 mA cm−2 at 900 and 800 °C. After polarization in the presence of the Fe–Cr interconnect at 900 °C for 20 h, electrode polarization resistance and overpotential of the O2 evolution reaction (OER) on the LSCF electrode are 0.413 Ω cm−2 and 127 mV, respectively, which is nearly 7 and 18 times the initial values of the electrode before the polarization. Significant performance degradation was also observed for the reaction at 800 °C in the presence of the Fe–Cr alloy. XRD and XPS analyses clearly identified the deposition of SrCrO4, CrO2.5 and Cr2O3 phases on the surface of LSCF oxygen electrodes and their formation is closely related to the increased segregation of the SrO species under anodic polarization conditions. Sr segregation leads to Sr deficiency at the A-site, thus deteriorating the electrocatalytic activity of the LSCF oxygen electrodes for OER. The results indicate that Cr deposition is essentially a chemical reaction and is initiated by the nucleation reaction between the gaseous Cr species and segregated SrO on the surface region of the LSCF oxygen electrode.

Graphical abstract: Chromium deposition and poisoning at La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrodes of solid oxide electrolysis cells

Article information

Article type
Paper
Submitted
04 Nov 2014
Accepted
18 Nov 2014
First published
27 Nov 2014

Phys. Chem. Chem. Phys., 2015,17, 1601-1609

Chromium deposition and poisoning at La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrodes of solid oxide electrolysis cells

B. Wei, K. Chen, L. Zhao, Z. Lü and S. Ping Jiang, Phys. Chem. Chem. Phys., 2015, 17, 1601 DOI: 10.1039/C4CP05110F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements