Hydrogen-incorporated vanadium dioxide nanosheets enable efficient uranium confinement and photoreduction

Photocatalytic reduction of U(VI) represents a novel and effective manner for the removal of U(VI) pollutant from radioactive wastewater. Herein, we successfully incorporated hydrogen into VO₂ nanosheets, which strengthened the interaction between VO₂ and U(VI), thereby achieving a highly active and stable photocatalyst for U(VI) reduction. With the increase of H content in hydric VO₂ (H_x-VO₂) nanosheets, the bandgap shrank from 2.29 to 1.66 eV, whereas the position of conduction bands remained more negative than the reduction potential of U(VI)/U(IV) (0.41 V vs. NHE). When irradiated by simulated sunlight, the U(VI) removal efficiency over H_0.613-VO₂ nanosheets reached up to 95.4% within 90 min, which largely outperformed 28.3% of pristine VO₂ nanosheets. The mechanistic study demonstrated that the hydroxylated surface gave rise to the balanced O confinement sites in VO₂ (011), leading to the stabilized adsorption configuration and increased binding strength of UO₂²⁺ on H_x-VO₂ nanosheets.