Fast uranium electro-extraction through synergistic hydrophilic channel and modulating local interfacial species

Capturing uranium from seawater and spent fuel storage phase identification for nuclear energy sustainable development represents the effective solution to carbon neutral. Here, we demonstrated boosting electrocatalytic uranium extraction on electrode consisted of 3D ethoxy substituted Ni oxalate (Ni-C2O4) nanowire spongs with the interlayer spacing and hydrophilic surface which are favourable for uranyl-specific liquid mass and fluid transfer. Thermodynamically stable U(VI or IV) phases were selected formation at 1.0 V and 2.5 V, respectively by alternation of the local spatial species including [UO2Cl]+, OH– or OH radical. Since the chemical reaction between UO22+ and in-situ generated OH–, insoluble Clarkeite NaUO2(OH)2 U(VI) phase formed with removal efficiency of 99 % after 30 min at a low cell voltage of 1.0 V. In comparison, at 2.5 V, it is found that yellow Studtite appeared as intermediate involved electro-generated OH radical species. Stable black UO2 is final reductive products, which is well understanding for uranium stockpile stewardship and waste processing.