Study on steam reforming of CH4 and C2 hydrocarbons and carbon deposition on Ni-YSZ cermets

Equilibrium partial pressure of oxygen and the boundary of carbon deposition region were calculated in the C---H---O phase diagram at temperatures ranging from 400 to 1000 °C. The open circuit voltage for the solid oxide fuel cell (SOFC) was directly connected to the calculated partial pressure of oxygen at higher temperatures. These calculations suggested that the development of the anode catalyst without carbon deposition was one of the most promising ways to achieve high efficiency in SOFC because the amount of added water could be reduced. The characteristics of steam reforming of methane and carbon deposition on Ni-Y2O3-stabilized zirconia (Ni-YSZ) cermets anodes were examined. The effect of MgO, CaO, SrO and CeO2 addition to Ni-YSZ cermets on their catalytic activity and carbon deposition was investigated. Although, the CaO addition slightly deteriorated the electrochemical activity as anode, the CaO addition was effective in suppressing carbon deposition and promoted steam reforming of CH4.