Self‐supportive Three‐Way Photoelectrochemical System Achieving Uranium Recycling, Organic Oxidation, and Electricity Generation in Complex Waters

Abstract A self‐sustaining solar photoelectrochemical cell (SS‐PEC) is present that recovers uranium from aqueous uranyl ions (UO 2 2+ ) with concurrent organic oxidation and electricity production. The employed a titanium dioxide (TiO 2 ) nanorod array photoanode (monolithically combined with a back Si solar cell) directly captures electrons from organic compounds, leading to the oxidation of organic compounds and the decomposition of uranium‐organic complexes. On the other hand, uranyl ions can be efficiently adsorbed and reduced on a three‐dimensional (3D) vanadium sulfide (VS 4 ) nanowire decorated carbon fiber felt (VS/CF) cathode. The chain‐like crystal structure of VS with exposed S 2 2− dimers favors the charge transfer and coordination with UO 2 2+ , while the V 5+ /V 4+ /V 3+ redox cycle facilitates the reductive recovery of UO 2 2+ . Consequently, organics are continuously photooxidized on the anode to provide electrons for reducing UO 2 2+ on the cathode with accompanying the electric current generation through the PEC cell. The proposed SS‐PEC system successfully operated in various complex water systems, including real uranium tailings wastewater, with high stability (for 30 repeated uses without obvious decay) and uranium recycling efficiency (92%). The excellent selectivity for UO 2 2+ adsorption on VS/CF is demonstrated by the far higher distribution coefficient K d (14,173 mL g −1 ) compared with other competing ions.