A comparative investigation on the thermochemical and catalytic properties of palladium oxide crystallite supported on monoclinic or tetragonal-doped zirconia, demonstrated that by sharing the interfacial atoms with monoclinic zirconia, PdO crystallite aggregates at the aid of this epitaxy on the support template to acquire better dispersion. Moreover, tracking the heating-cooling cycles in air atmosphere, DTG analysis illustrated that the crystallized PdO gradually transforms into the epitaxial PdO species on the monoclinic zirconia and the improved mobility of oxygen in lattices promotes the oxidative regeneration of PdO at high temperature thereby. Combining the above two superiorities on aggregation forms of PdO, the template of monoclinic zirconia inhibits the high temperature deactivation of catalysts for methane combustion, meanwhile, increases the stability of combustion reaction and the sustainability of catalysts. However, the doping of tetragonal zirconia into monoclinic support muffles those advantages prominently.

Key words: catalytic combustion, palladium catalyst, epitaxy, thermal analysis