Morphological and catalytic stability of mesoporous peony-like ceria

Abstract

Mesoporous peony-like ceria has been previously investigated to exhibit superior catalytic properties for CO oxidation, ethanol reforming and anode catalysts for low temperature SOFC. In this work, morphological and catalytic stability are investigated upon heat treatments in reducing and oxidizing atmosphere at temperatures between 300 and 600 °C. Although the peony-like appearance remains stable upon heat treatment at 600 °C for up to 72 h, the BET surface area decreases from 150 to 30 m 2g −1 with nanocrystalline size increased from 6 to 15 nm. Catalytic activity of CO oxidation decreases such that T 50 (temperature for 50% conversion) increases from 153 to 197 °C. Although morphological variation is more prominent significant upon treatment in reducing atmosphere, the catalytic activity for CO oxidation degrades less than in oxidizing atmosphere. Oxygen vacancies produced upon reduction treatment are responsible for the superior catalytic activity despite the morphological disadvantage.