CO Oxidation to CO2 on Uranium Dioxide Molecules through Intermediate O2U(η1-CO).

Investigations on the reactions of uranium oxide molecules with CO offer new inspiration for the design of promising high-efficiency catalysts for CO activation using actinide materials. Herein, we contribute a combined matrix-isolation infrared spectroscopic and theoretical study of CO oxidation to CO2 on uranium dioxide (UO2) molecules in solid argon. The reaction intermediate O2U(η1-CO) is generated spontaneously at the bands of 1893.0, 870.6, and 801.3 cm-1 during codeposition and annealing. Upon the following irradiation, CO2 is substantially produced by the consumption of O2U(η1-CO), indicating the catalytic conversion of CO to CO2 through the intermediate O2U(η1-CO). In C18O isotopic substitution experiments, the yields of 16OC18O convincingly confirm that one of the oxygen atoms in CO2 derives from UO2. The reaction pathways are discussed based on the theoretical and experimental results.