Hydrogen-incorporated vanadium dioxide nanosheets enable efficient uranium confinement and photoreduction
Huanhuan Liu, Jia Lei, Jiali Chen, Ye Li, Changyao Gong, Shangjie Yang, Yamin Zheng, Ning Lü, Yan Liu, Wenkun Zhu, Rong He
Abstract
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 VO 2 nanosheets, which strengthened the interaction between VO 2 and U(VI), thereby achieving a highly active and stable photocatalyst for U(VI) reduction. With the increase of H content in hydric VO 2 (H X -VO 2 ) 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 -VO 2 nanosheets reached up to 95.4% within 90 min, which largely outperformed 28.3% of pristine VO 2 nanosheets. The mechanistic study demonstrated that the hydroxylated surface gave rise to the balanced O confinement sites in VO 2 (011), leading to the stabilized adsorption configuration and increased binding strength of UO 2 2+ on H X − -VO 2 nanosheets.