Enhanced oxygen-release/storage properties of Pd-loaded SrFeO.

This study proves that a small amount of Pd loading (1 wt%) on SrFeO can dramatically enhance the oxygen-storage properties of SrFeO. The topotactic oxygen intake and release between SrFeO and SrFeO takes place in response to gas switching between an O flow and H flow, regardless of the presence or absence of Pd loading. The effect of Pd loading is significant for the oxygen-release process under H atmosphere; that is, highly dispersed Pd metal nanoparticles sized less than 1 nm formed on Pd/SrFeO to promote H dissociation, resulting in the improvement of the oxygen-release temperature and rate. Pd/SrFeO with a layered perovskite structure has a higher oxygen-release property at lower temperature than Pd/SrFeO with a perovskite phase without the layered structure. These facts indicate that the surface reaction as well as the crystal structure are responsible for the oxide ion mobility in perovskite structure, and also provide guidelines for designing novel oxygen-storage materials.