Effect of Ce Doping on the Performance and Stabili

Authors: Hyunkyu Choi Anshuman Fuller Doruk Dogu Katja E Binkley Jonathan Davis Anne Co Umit S Ozkan

Publish Date: 2015/03/06

Volume: 58, Issue: 4-6, Pages: 359-374

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Abstract

The bulk structure surface characteristics catalytic properties button cell performance and stability of perovskitetype oxides with the formula Sr1−xCexCo02Fe08O3−δ x = 010 015 and 020 were investigated as potential anode electrocatalysts for solid oxide fuel cells In situ Xray diffraction results indicated that the structural stability of the ceriumdoped perovskites was enhanced with increasing cerium concentration The catalysts with lower cerium concentration transformed from the initial cubic structure to a lower symmetry structure at high temperatures in a reducing environment All the catalysts however were restored to the original cubic structure after reoxidation Electronic conductivity tests showed that the ceriumdoped samples break down at higher temperatures but display potential in terms of structural integrity and high conductivity at temperatures lower than 600 °C The new materials showed better performance than Ni–YSZ in catalytic methane oxidation tests The sulfur tolerance is significantly enhanced with the ceriumdoped perovskites showing no deactivation for up to 10 h of operation under 50 ppm H2S Xray photoelectron spectroscopy analysis on the poisoned samples suggests that the sulfur may exist on the surface primarily as strontium sulfate The sample with a cerium loading of 15  x = 015 showed a particularly high sulfur tolerance during chronoamperometry tests and its button cell performance matched well with that of Ni–YSZ anode Sr1−xCexCo02Fe08O3−δ x = 010 015 and 020 samples may have potential for low or intermediate temperature SOFC operation in which sulfurcontaining hydrocarbon fuels are used although they would not be stable at higher temperatures

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