Physically mixed LiLaNi-Al₂O₃ and copper as conductive anode catalysts in a solid oxide fuel cell for methane internal reforming and partial oxidation

Different concentrations of copper are added to LiLaNi-Al₂O ₃ to improve the electronic conductivity property for application as the materials of the anode catalyst layer for solid oxide fuel cells operating on methane. Their catalytic activity for the methane partial oxidation, steam and CO₂ reforming reactions at 600-850 °C is systematically investigated. Among the three catalysts, the LiLaNi-Al₂O ₃/Cu (50:50, by weight) catalyst presents the best catalytic activity. Thus, the catalytic stability, carbon deposition and surface conductivity of the LiLaNi-Al₂O₃/Cu catalyst are further studied in detail. O₂-TPO results indicate that the coking resistance of LiLaNi-Al₂O₃/Cu is satisfactory and comparable to that of LiLaNi-Al₂O₃. The surface conductivity tests demonstrate it is extremely improved for LiLaNi-Al₂O₃ catalyst due to the addition of 50 wt.% copper. A cell with LiLaNi-Al ₂O₃/Cu (50:50) catalyst layer is operated on mixtures of methane-O₂, methane-H₂O and methane-CO₂, and peak power densities of 1081, 1036 and 988 mW cm^-2 are obtained at 850 °C, respectively, comparable to the cell with LiLaNi-Al ₂O₃ catalyst layer. In summary, the results of the present study indicate that LiLaNi-Al₂O₃/Cu (50:50) catalysts are highly coking resistant and conductive catalyst layers for solid oxide fuel cells.