Rational construction of defective Z-Scheme tandem heterojunction interfacial charge transfer channels for efficient uranium collection and resistance to biological contamination

Designing an efficient reduction of soluble U(VI) to insoluble U(IV) is a challenge, and efficient electron-hole transfer efficiency is the key to the conversion of U(VI) to U(IV). Herein, defective transition metal sulfide (O v -ZAF) Z-Scheme tandem heterojunctions with spatial separation were synthesized using an in situ self-assembly method. O v -ZAF has excellent electron-hole separation, stabilized reactive active sites, and excellent visible light absorption. O v -ZAF is able to realize the photocatalytic U(VI) reduction reaction (URR) and water oxidation reaction (WOR) synergistically. The results showed that O v -ZAF was able to reduce 498.3 mg/g of U(VI) in 100 ppm uranium solution for 200 min, with a reduction efficiency of 99.8 %. O v -ZAF showed excellent reduction ability in a variety of uranium-containing waste solutions as well as in real seawater. In addition, O v -ZAF is capable of generating reactive oxygen radials (ROS) and has excellent antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudoalteromonas xiamen . Oxygen vacancies and tandem components can tune both occupied and unoccupied orbitals near the Fermi level of O v -ZAF. This work provides a possibility of efficient uranium reduction engineering through tunable compositions and electronic structures.