Catalysts and performances for direct methanol low temperature (300 to 600°C) ceramic fuel cells

Low temperature (300 to 600°C) ceramic fuel cells promise high efficiencies in a range of fuels other than pure hydrogen. In this case, liquid hydrocarbon fuels, e.g., methanol can be easily thermally decomposed to H2 and CO that can be directly used for fuel cell operation without external reformer leading to simple system and high efficient operation. In the present work, a novel anode catalyst C-MO-CeO2 (C=activated carbon/carbon black, M=Cu, Ni, Co) was synthesized employing citrate/nitrate combustion technique. And acceptable performances, e.g. power intensity of 0.20 W cm-2, were achieved by directly operating the methanol at 560°C. Also the carbon deposition and cracking on anode were studied as thermal decomposing of methanol. Transition metal oxides of CuO with n-type conductivity and NiO, CoO with p-type conductivity, possess catalytic activity of the electrochemical oxidation for liquid hydrocarbon fuels. CeO2 becomes an oxide-ion and electron mixed conductor in the reducing fuel environment, which can expand the reaction zone beyond three-phase boundaries, can store and transfer oxygen ions, so it can also enhance the catalytic oxidation of methanol. In addition, carbon materials e.g., activated carbon and carbon black were used to improve the characters of anode materials, especially to enhance the anode electronic conductivity and catalyst function to liquid hydrocarbon fuels. In contrast to LaCrO3-based, Ni-YSZ-based anode materials, C-MO-CeO2 can be synthesized more economically. Thus there arc considerable interests and demands in finding alternative anodes composites.