Effect of hydrogen sulfide inclusion in syngas feed on the electrocatalytic activity of LST-YDC composite anodes for high temperature SOFC applications

The performance of La0.4Sr0.6TiO3±δ-Y0.2Ce0.8O2−δ (LST-YDC) composite anodes in solid oxide fuel cells significantly improved when 0.5% H2S was present in syngas (40% H2, 60% CO) or hydrogen. However, electrochemical impedance spectroscopy measurements at OCV showed that polarization resistance of the cell increased when the concentration of H2S exceeded 0.5%. Gas chromatographic and mass spectrometric analyses revealed that the rate of electrochemical oxidation of all fuel components improved when H2S was present in the fuel. Electrochemical stability tests performed under potentiostatic conditions showed that there was no power degradation caused by the presence of H2S in different feeds, and that there was power enhancement when 0.5% H2S was present.

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► We synthesized La0.4Sr0.6TiO3-Y0.2Ce0.8O2 composite as the stable and active anode catalyst for H2S (0.5%)-containing syngas feed.
► Cell performance enhances by adding H2S into syngas.
► The presence of H2S enhances the electrochemical oxidation of feed.
►  H2S is not consumed and no SO2 is produced during potentiostatic and potentiodynamic runs.
► No power density loss observed during several days operation.