Isotopic Oxygen Exchange between CeO2 and O2: A Heteroexchange Mechanism
Isotopic oxygen exchange (IOE) is a crucial reaction required in the purification of 238PuO2 which has been used as an important fuel in space exploration. Experimental studies on the IOE between 238PuO2 and O2 are costly and hazardous due to the radioactivity. With extremely similar crystal structures, CeO2 could be a fair surrogate for 238PuO2 in the investigation of physicochemical properties. Here, we perform density functional theory calculations to simulate the IOE between CeO2 and O2, wherein a heteroexchange mechanism is proposed. Estimated reaction barriers for CeO2/O2 and 238PuO2/O2 systems are comparable (25.8 and 29.3 kcal mol−1 respectively), indicating CeO2 is a potential substitute for 238PuO2 in an IOE reaction. Our study could be useful for experimental chemists to probe more complicated IOE mechanisms for both CeO2/O2 and PuO2/O2.