A self-driven solar coupling system with TiO@MXene cathode for effectively eliminating uranium and organics from complex wastewater accompanying with electricity generation.

The inevitable organic matters in radioactive wastewater and contaminated waters pose great challenge in uranium recycling by traditional techniques. Here, a self-driven solar coupling system (SSCS), which was assembled by a TiO @MXene/CF cathode and a monolithic photoanode, was proposed for synergistically recycling uranium and degrading organics from complex radioactive wastewater, combining with electricity production. The TiO @MXene/CF was prepared via a simple annealing process with in-situ derived TiO nanoparticles decorated TiC MXene coated on carbon felt (CF). Under sunlight illumination, the photoanode captured electrons of organics, and drove electrons to the TiO @MXene/CF, which exhibited an exceptional UO adsorption and reduction capacity because TiO nanoparticles provided plenty of surface hydroxyl groups for UO adsorption, and the unique two-dimensional MXene facilitated the charge transfer. The SSCS with TiO @MXene/CF removed almost 100% UO and organics with rate constants of ∼21 and ∼6.9 times those of the system with CF, accompanying with excellent power output (∼1000 μW·cm). The fixed uranium on TiO @MXene/CF was effectively reduced into insoluble UO (91.1%), and no obvious decay was observed after 15 repeated uses. This study proposes a multi-functional and easy-operated way for remediating radioactive wastewater and contaminated waters, and gives valuable insights in designing cathode materials for uranium reduction.