Isotopic Oxygen Exchange between CeO₂ and O₂: A Heteroexchange Mechanism

Abstract

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.

Atomic level fluxional behavior and activity of CeO2-supported Pt catalysts for CO oxidation

“…On the other hand, it is generally well known that the molecular dissociation and gas-phase exchange of O 2 is energetically much more challenging, with theoretical calculations and experimental isotopic oxygen exchange measurements placing the activation energy over CeO 2 around 1.1 eV 39 , 40 . Hence, here we speculate that the observed fluxional behavior is associated with the energetically more facile steps of lattice oxygen abstraction by CO, and that the absence of measurable conversion is due to the lack of oxygen vacancy back-filling from molecular O 2 exchange.…”

Self‐Assembled Two‐Dimensional NiO/CeO2 Heterostructure Rich in Oxygen Vacancies as Efficient Bifunctional Electrocatalyst for Alkaline Hydrogen Evolution and Oxygen Evolution

“…CeO 2 , one kind of rare earth oxide, exhibits outstanding redox properties, as it possesses a redox couple of Ce 4+ /Ce 3+ with low redox potential, which can be mutually converted under redox conditions [29, 30] . So far, CeO 2 has been used widely as a hydrogen storage material, oxygen storage material, gasoline catalyst, and so on [31–33] .…”

“…CeO 2 ,o ne kind of rare earth oxide, exhibits outstanding redox properties, as it possesses ar edox couple of Ce 4 + /Ce 3 + with low redoxp otential, which can be mutually converted under redox conditions. [29,30] So far,C eO 2 has been used widely as ah ydrogen storage material, oxygen storage material, gasoline catalyst, and so on. [31][32][33] However,i ts application in the HER and OER has been limited.R ashid et al [34] reported at ernary composite of graphitic carbon nitride, CeO 2 ,a nd Fe 3 O 4 as an alkalineH ER and OER catalyst for the first time, demonstrat-ing that the synergistic effect between CeO 2 and Fe 3 O 4 dramatically enhances the catalytic property.T hus, the design and synthesis of at ransition metal oxide/CeO 2 catalystf or the HER and OER in alkaline surroundingsi sm eaningful.…”