Spectroscopic Investigation of the Photochemistry of Uranyl-Doped Sol-Gel Glasses Immersed in Ethanol

Uranyl ion (UO₂²⁺) has been doped in silica glasses through a sol-gel process. The photochemistry of UO₂²⁺-doped glasses immersed in ethanol solution has been investigated. Our experimental results indicate that UO₂²⁺ in this system can be photochemically converted to U(IV) species, and evidence is provided for the possible formation of U(IV) species via a subsequent chemical reduction of the intermediate UO₂⁺ instead of the conventional bimolecular disproportionation reaction. The latter mechanism is known to be a dominant mechanism for the photochemical reactions in homogeneous solutions.