Reactions of low concentration dry methane at Ni-YSZ anode in the SOFCs

Dry methane with various concentrations was directly entered the anode of the solid oxide fuel cells (SOFCs) of Ni-YSZ/YSZ/LSM(Ni-Y2O3 stabilized ZrO/YSZ/La0.85Sr0.15MnO3-δ). The exhaust gases from anode were measured in-situ by gas chromatograph (GC) to study the reactions of dry methane under different current densities at the Ni-YSZ anodes. The reactions were determined by comprising the theoretical open-circuit voltage (OCV) to the measured one, analyzing quantitatively the exhaust gas and the activation energy of elementary reactions occurred to CH4 at the Ni-YSZ anodes. At 1000°C oxidation of methane was found to take place in sequence from partial oxidation, CH4 + 2O2-→CO + H2O + H2 + 4e−, CH4 + 3O2-→ CO +2H2O + 6e− to complete oxidation with increasing current density at the Ni-YSZ anodes under 3.85% and 5.66% CH4 conditions.