Oxygen storage properties and catalytic activity of layer-ordered perovskites BaY1 − xGdxMn2O5 + δ

Crystal structure, oxygen storage-related and preliminary anaerobic methane combustion studies were conducted for BaY1 − xGdxMn2O5 + δ (0, 0.25, 0.5, 0.75 and 1) series of oxides prepared by a sol-gel method. All samples were found to possess layered-type A-site cation ordering, with the unit cell volume linearly dependent on the average radius of Y1 − xGdx for both the reduced and the oxidized materials. The oxygen content in the temperature range of 400 °C-600 °C indicates change on the order of 1 atomic mole, occurring when the sample's surrounding atmosphere was changed from air to 5 vol.% H2 in Ar. The time dependence of the reduction shows activated character on temperature, with an activation energy, which seems to be related to the oxygen diffusion in the bulk of the materials. Initial data concerning methane combustion in oxygen-free conditions show promising catalytic activity of BaYMn2O6 at elevated temperatures.