Oxygen Release and Storage Property of Fe-Al Spinel Compounds: A Three-Way Catalytic Reaction over a Supported Rh Catalyst.

We evaluated the catalytic performance of the Rh-Fe/Al2O3 catalyst during a three-way catalytic reaction and found, by chance, that a part of Fe species was dissolved into the γ-Al2O3 support and worked as an oxygen storage material, which adjusts the oxygen concentration around the catalytically active sites to a suitable level for three-way catalysis. In this study, we demonstrated that the Fe-doped γ-Al2O3 can reversibly store and release oxygen by the redox of Fe2+/Fe3+ at the tetrahedral (Td) site of the spinel structure without its structure deformation. The finding that a spinel-structured metal oxide, Fe-doped γ-Al2O3, could work as an oxygen storage material suggested a new opportunity for the development of oxygen storage materials without rare metals.