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Abstract: Hydrogen sulfide, usually considered to be an anode catalyst poison, strongly promotes methane oxidation over sulfur resistant catalysts. The role of H2S in oxidation of sour CH4 feed over a sulfur resistant SOFC anode catalyst at 850°C has been determined through thermodynamic and experimental studies. The anode material was an intimately mixed 50/50 mass ratio composite of La0.4Sr0.6TiO3−δ and YSZ. The power density improved dramatically from 2mWcm−2 with pure CH4 as fuel to more than 450mWcm−2 for CH4 containing 20% H2S. However, H2S was not the only fuel converted, and its interaction with CH4 was the key factor in enhancement of performance. The anode effluent gas mixture included H2S, SO2, H2 and CS2 consistent with thermodynamic predictions. The role of H2S in the CH4 oxidation mechanism was determined, and showed that CH4 and H2S must be considered together as a fuel and not as two separate fuels. The types of electrochemical reactions that occurred in the fuel cell were strongly dependent on potential. [Copyright &y& Elsevier]

In situ exsolution of Co nanoparticles on perovskite framework has been successfully synthesized by firing the porous precursor SrMo 0.8 Co 0.1 Fe 0.1 O 3-δ (SMCFO) in reducing flow at 850 °C. A structure transformation (from mixed to pure cubic phase) and the growth of Co nanoparticles are observed in H 2 atmosphere. This leads to an increase in the oxygen vacancy content, which is beneficial to the electrical conduction and catalytic activity towards the oxidations of H 2 and C 2 H 6 . Moreover, this material exhibits good redox reversibility under the condition of multiple reduction and re-oxidation cycles, as confirmed by the thermogravimetric analysis (TGA) measurements. A protonic fuel cell (PFC) built with this newly developed material shows a comparable electrocatalytic activity in both C 2 H 6 and H 2 atmospheres while a considerably high power density of 377 mW cm −2 is achieved in H 2 and 268 mW cm −2 in C 2 H 6 at 750 °C. In addition, C 2 H 4 yield in the cell with Co-SMCFO as anode is considerably improved (11.9%–37.8% at 650–750 °C) with respect to the widely used chromium oxide. The good electrochemical performance, the improved C 2 H 6 partial dehydrogenation ability and the negligible carbon formation in the Co-SMCFO anode are the strong indications that the SMCFO is a promising catalyst for the cogeneration of C 2 H 4 and electricity, and can also be potentially utilized in the PFC directly fueled with hydrocarbon. [ABSTRACT FROM AUTHOR]