A novel PdO/La10Si6O27/γ-Al2O3 catalyst was developed in order to decompose methane. In this catalyst, we selected the oxide-ion-conducting La10Si6O27 solid with an apatite-type structure as a promoter to facilitate the supply of active oxygen to the PdO activator. For the comparison with PdO/La2O3/γ-Al2O3, where La2O3 is a simple rare earth sesquioxide, the catalytic activity of PdO/La10Si6O27/γ-Al2O3 was higher than that of PdO/La2O3/γ-Al2O3, regardless of their same surface area. Since La10Si6O27 exhibited two orders of magnitude higher conductivity than La2O3, the high oxide-ion-conducting property of La10Si6O27 might facilitate the oxidation of methane by supplying active oxygen from inside the lattice.
2017 The Ceramic Society of Japan