1 T@2H-phase MoS2 quantum dot-modified oxygen-rich vacant ZnO for the photo-reduction of uranium without sacrificial agents

Efficient and stable photocatalytic materials are urgently needed for the photo-reduction of uranium in wastewater treatment without the addition of external sacrificial agents under air conditions. Herein, we designed and synthesized 1 T@2H MoS 2 QDs (MSQ) modified oxygen-rich defective ZnO photocatalysts 1 T@2H MoS 2 QDs/OV-ZnO (MSQVZO) and systematically investigated its photocatalytic U(VI) activity in various matrices, which exhibited 97 % removal efficiency of uranium after 40 min of visible light irradiation under aerobic conditions, and the order of photocatalytic activity was MSQVZO > OV-ZnO >  ZnO. XRD, ESR, XPS, and UV–vis were used for the characterization of the materials. In addition, it was argued using DFT analysis that the introduction of oxygen defects drove the OV-ZnO to interact with the intermediates of the oxygen evolution reaction (OER) reaction more readily than the ZnO, thus improving the activity of the OV-ZnO-based catalysts. More importantly, a new mechanism for photo-reduction of U(VI) was established. It provides an effective strategy for the photo-reduction of U(VI) without a sacrificial agent.