Ti3C2Tx/Cd0.8Zn0.2S composites constructed of Schottky heterojunction for efficient photocatalytic reduction of U(VI).

ABSTRACT

Photocatalysis has emerged as a extremely promising green technology for the treatment of uranium-containing wastewater. This study focuses on the fabrication of Ti3C2Tx/Cd0.8Zn0.2S composites with Schottky junctions through the in-situ growth of Cd0.8Zn0.2S on Ti3C2Tx nanosheets, enabling efficient photoreduction of U(VI) without the requirement of sacrificial agents. The results demonstrate that the Ti3C2Tx/Cd0.8Zn0.2S composites achieve remarkable 99.48 % U(VI) reduction efficiency within 60 min in a 100 ppm uranium solution. Furthermore, the removal rate remains above 90 % after five cycles. The formation of Schottky heterojunctions by Ti3C2Tx and Cd0.8Zn0.2S leads to the generation of an internal electric field that significantly promotes the rapid separation and transfer of photogenerated carriers, thereby enhancing the photocatalytic reduction efficiency of Ti3C2Tx/Cd0.8Zn0.2S-3100 (TC/CZS-3100). A considerable amount of electrons accumulate on Ti3C2Tx via the Schottky barrier, effectively facilitating the reduction of U(VI) to U(IV). As a co-catalyst, Ti3C2Tx enhances the photocatalytic performance and stability of Cd0.8Zn0.2S. Moreover, the practical application in the waste liquid of rare earth tailings reveals that the removal rate can be as high as 91.24 %. This research is of significant value in the development of effective photocatalysts for the elimination of uranium from wastewater.