Photocatalytic Conversion of Am(III) to Am(VI) Using a TiO2 Electrode

Titanium-titania (Ti vertical bar TiO2) nanostructured electrodes in 0.1 M HNO3 solutions under UV-light illumination using a 375 nm LED and a 1.55 V vs SCE bias photoelectrochemically oxidize Am(III) to Am(VI) ((AmO22+)-O-VI). Oxidation occurs through photoelectrochemically generated adsorbed hydroxyl radicals (2.81 V vs SCE) and/or direct electron transfer between the excited-state electrode (E(TiO2VB*) = ca. 2.95 V vs SCE) and Am(III) (E(Am-IV/III) = 2.62 V). An electrochemically irreversible but chemically reversible electrochemical process at 1.60 V vs SCE is assigned to the one-electron Am(VI/V) couple. This system may be applied to used nuclear fuel reprocessing to separate actinides of concern (U, Np, Pu, and Am), where Am is the most significant challenge.

Automated summary

Titanium-titania nanostructured electrodes were used to photoelectrochemically oxidize Am(III) to Am(VI) in 0.1 M HNO3 solutions under UV-light illumination. The oxidation process occurred through the generation of adsorbed hydroxyl radicals or direct electron transfer. The one-electron Am(VI/V) couple at 1.60 V vs SCE can be applied in nuclear fuel reprocessing, with Am being the main challenge.