Mapping electrochemically driven gas exchange of mixed conducting SrTi0.7Fe0.3O3 - δ and Ce0.8Gd0.2O1.9 thin films by 18O tracer incorporation under reducing atmosphere

Andreas Nenning; Edvinas Navickas; Peter Velicsanyi; Alexander K Opitz; Herbert Hutter; Jürgen Fleig

doi:10.1016/j.ssi.2014.10.024

Mapping electrochemically driven gas exchange of mixed conducting SrTi_0.7Fe_0.3O_{3 - δ} and Ce_0.8Gd_0.2O_1.9 thin films by ¹⁸O tracer incorporation under reducing atmosphere

Solid State Ion. 2015 May:273:25-29. doi: 10.1016/j.ssi.2014.10.024.

Authors

Andreas Nenning¹, Edvinas Navickas¹, Peter Velicsanyi¹, Alexander K Opitz¹, Herbert Hutter¹, Jürgen Fleig¹

Affiliation

¹ Vienna University of Technology, Institute of Chemical Technologies and Analytics, Getreidemarkt 9/164, 1060 Vienna, Austria.

Abstract

Thermally and electrochemically driven ¹⁸O tracer exchange experiments in H₂/H₂¹⁸O atmosphere were performed on SrTi_0.7Fe_0.3O_{3 - δ} and Ce_0.8Gd_0.2O_{2 - δ} thin films on single crystalline YSZ substrates. Noble metal current collectors were deposited on both films and electrochemically polarized during the exchange experiment. The resulting tracer distribution was analyzed by spatially resolved secondary ion mass spectrometry. Increased tracer fraction near the current collectors was found under cathodic polarization and decreased tracer fraction under anodic polarization. High cathodic bias leads to enhanced n-type electronic conductivity, which increases the extent of the electrochemically active zone.

Keywords: 18O enriched water; Electrochemical water splitting; Electrochemically active zone; Isotopic surface exchange; Thin film electrode.