In this study, an inexpensive and abundant FeOx-based catalyst was developed as a three-way catalyst (TWC). The deactivation associated with the fusion and aggregation of metallic iron under high-temperature reducing conditions was solved by the formation of FeOx-ZrO2 nanostructures. Furthermore, high dispersibility of FeO2 in the nanostructures and multiple pores were successfully formed using a supercritical CO2 drying. As a result, the oxygen storage capacity of the FeOx increased dramatically and high stability was obtained. In a TWC reactivity evaluation, the FeZr-TWC showed a high performance similar to that of the commercially available CeO2-based TWC. Even after aging treatment for 20 h at 1000 degrees C under a 10 vol% steam condition, an NOx(T-80,T- NOx) conversion of greater than 80% was successfully achieved, whereas it was not achieved by the standard TWC. Therefore, the FeZr nanostructures are expected to have sufficient capacity to replace the conventional CeO2-based TWCs.