Study On Electrocatalyst Of Direct Oxidation Of Methane On Anode Of Solid Oxide Fuel Cell

The electrocatalyst for SOFC with direct oxidation of methane at anode was designed, prepared, characterized and its activity was evaluated. The solid oxide fuel cell was set up and its performance was tested with the aim of achieving more deep understanding on direct application of methane on SOFC.Based on both theories of heterogeneous catalysis and the special requirements of electrode for SOFC, electrocatalyst design principles were proposed as follows: first, the activity of total oxidaton of methane, second, the ion-electron mixed conductivity and third, the propriate microstructure. The catalyst system designed based on above principles was rare earth element as La doped Cu-Ce-Zr catalyst. The interaction among components was discussed in detail as well.Four methods were applied to prepared eletrocatalyst, as impregnation, coprecipitation, sol-gel and sol-gel &impregnation. Sol-gel and coprecipitation was prior to the other two method as to catalyst activity and selectivity due to the fact the content of cubic and tetragonal structure in catalyst were higher than that of impregnation.The effect of CeO₂ in catalyst was studied. The activity of catalyst was improved with increasing CeO₂ content. The addition of CeO₂ was benefit to Cu dispersion and influence the distribution of Cu species on catalyst surface. Cu⁺ could be stabilized in Ce-Zr-O lattice. And the multi-valance of copper increased redox ability of Ce. CeO₂ also affected surface oxygen species which changed from O^2- to the mixture of O^2- and more active O₂^2-. The effect of CeO₂ on performance of SOFC was investigated. Ceria could greatly improved power density of SOFC, low-down polarization. The redox activity of Ce⁴⁺/Ce³⁺ pair was proposed to be one of the most important factor which influence catalyst activity based on result of activity evaluation and catalyst characterization.The effect of Cu content on catalyst activity was studied . Although Cu is a weak catalyst to active C-H bond, dispersion of copper in Ce-Zr-O matrix could improve...