Visible light driven Ti3+ self-doped TiO2 for adsorption-photocatalysis of aqueous U(VI)

The photocatalytic reduction of U(VI) is recognized as an economical and effective way for U(VI) removal/recovery from solutions. To improve the photocatalytic activity of TiO 2 under visible light, TiO 2 was hydrogenated by NaBH 4 to generate Ti 3+ self-doped black TiO 2 (BT n ). The self-doped Ti 3+ alongside oxygen vacancies (Ov) could act as interband level to increase visible light capture and reduce the recombination of photogenerated carriers. The obtained BT n samples showed high performance for U(VI) elimination under near neutral conditions, and held an outstanding anti-interference for U(VI) over competing metal cations and anions. Methanol and ethanol could act as sacrificial donors, being favorable for the photocatalytic reduction of U(VI), while the presence of EDTA inhibited the photoreduction of U(VI). The BT n photocatalysts showed relatively high stability and reusability during the photocatalysis and elution processes. The XPS, TEM and XRD results revealed that U(VI) was photo-reduced to form UO 2 on the surface of BT n . This work may serve as an important reference for improving the photocatalytic reactivity of TiO 2 as well as for the efficient removal/recovery of U(VI) from aqueous solutions.