Structural and Oxygen Storage Properties of Hexagonal Manganites

Complex oxides exhibiting superior reversible oxygen absorption/release capacities have been generating a great deal of interest due to their critical role in the development of energy related technologies, such as oxy-fuel and chemical looping combustion. Based on our previous studies of tolerance factor, we have successfully synthesized hexagonal (P6$_{3}$cm) RMnO$_{3+\delta}$ manganites (R$=$Dy, Ho, Y) for which we discovered a large reversible oxygen storage/release capacities (within the range of oxygen content 3.0 - 3.4) at unusually low temperatures near 300 $^{\circ}$C which make them excellent candidates for air separation and production of high purity oxygen. Resistivity, structural, magnetic, and thermal expansion properties are correlated with the oxygen content 3$+\delta $ for these compounds. Work supported by NIU Great Journey Assistantship.