Insights into performance metrics of SOFC anodes for methane electro-oxidation

Large number of perovskite materials like La_1-xSr_xCr_1-yMn_yO₃ (LSCM), La_1-xSr_xCa_1-yTi_yO₃ (LSCT), La_1-xSr_xTiO₃ (LST) and Sr_1-xY_xTiO₃ (YST) are proposed as suitable anode material for solid oxide fuel cells (SOFC). These perovskite structures are mixed ionic and electronic conductors (MIEC) which extend the triple phase boundary (TPB) deep into the anodes for electro-chemical reactions with high stability in redox environment. Impregnating of catalyst particles like; nickel (Ni), copper (Cu), palladium (Pd) and ceria (CeO₂) into the porous structure of MIEC anodes enhances electro-oxidation of methane. Although traditional NiO-YSZ anodes are being replaced by perovskite structures, the electro catalytic activity of perovskite anodes for methane oxidation is still not quantified. Traditional NiO-YSZ anodes are well characterized using a 3-electrode configuration to provide exchange current density values for methane electro-oxidation. A similar approach is missing in case of perovskite anodes impregnated with active electro catalysts. In this work, the exchange current density values of traditional NiO-YSZ anodes impregnated with various metal oxides are compared with uni-doped (La_0.3Sr0_.5TiO_3δ) and bi-doped (La_0.3Y_0.1Sr_0.4TiO_3-δ) strontium titanate anodes impregnated with NiO and CeO₂. Various physical and structural characterization techniques are used to account for structural changes in the anodes which give rise to better performance in methane. The first part of the work emphasis on NiO-YSZ anode impregnated with different metal oxides like, CeO₂, CuO, etc. for methane oxidation