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

Uranyl ion (UO2 2+) has been doped in silica glasses through a sol−gel process. The photochemistry of UO2 2+-doped glasses immersed in ethanol solution has been investigated. Our experimental results indicate that UO2 2+ 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.