Here, our recent study on the oxygen-storage materials BaLnMn2O5+δ with Ln = La, Nd, Gd, and Y is reviewed. The redox characteristics of these materials were systematically investigated employing the reductive water dissolution by the deoxygenated δ = 0 form. The Ln = La, Nd, and Gd compounds were found to show a capability to produce hydrogen gas through the water dissolution at 500 oC, whereas the Ln = Y compound was unreactive to water. The present study also revealed that the reactivity significantly depends on the Ln species: the larger the Ln3+ ionic size, the higher reactivity the BaLnMn2O5.0 samples exhibit. The experimental data were discussed on the basis of thermodynamic energetics by quantum chemical calculations.
Keywords:oxygen storage materials, BaLnMn2O5+δ, reductive water dissolution, thermodynamics, quantum chemical calculations
Publication Date: 2017-01-20