Importance of pyrolysis and catalytic decomposition for the direct utilization of methanol in solid oxide fuel cells

There is interest in developing solid oxide fuel cells (SOFC) operated directly with liquid fuels such as methanol. This mode of operation increases the complexity of the anodic processes, since thermal and catalytic decomposition reactions are relevant. In this study, the pyrolysis and catalytic decomposition of methanol are investigated experimentally for conditions typical of SOFC. The results are compared to the thermodynamic equilibrium values and also to the predictions of a kinetics model. The main species of the thermal decomposition of methanol are H-2, CO, and HCHO; soot formation is relevant below 973 K. The presence of a catalyst allows the gas-phase composition to reach equilibrium. However, the catalysts tested - Ni/YSZ, Ni/CeO2, Cu/CeO2 and Cu-Co/CeO2 - deactivate by coking so that the gas-phase composition reverts to that of pyrolysis alone. The results presented reveal part of the complex dynamics occurring within the anode compartment during the direct utilization of methanol. (C) 2009 Elsevier B. V. All rights reserved.