Precise Electrocatalysis on Fe-Porphyrin Conjugated Networks Achieves Energy-Efficient Extraction of Uranium.

Electrochemical extraction has the potential to enhance uranium (U) extraction capacity and rates, but thus far, high selectivity and energy efficiency have not been achieved through the design of electrode materials. Herein, a precise electrocatalysis strategy is developed using a Ferrum (Fe) porphyrin-phenanthroline conjugated network (Fe@PDACN) for energy-efficient uranium extraction. The phenanthroline provides specific binding sites for selective enrichment of U(VI) at active sites (K = 2.79 × 10 mL g in multi-ion solution). The Fe(II) sites have strong trap-redox activity for U(VI) and act as dynamic electron donors to rapidly mediate electrocatalytic U(VI) extraction through the redox reaction of Fe(0/II)/Fe(III). Moreover, the Fe-porphyrin blocks support sustained electron donation for U(VI) electrocatalysis by pre-storing electrons. These features enable selective uranium capture and a high electroextraction capacity of 24 646.3 mg g from simulated nuclear wastewater in 280 h at a low voltage of -1.5 V. An ultra-high Faraday efficiency of 90.1% is achieved, and the energy cost is 3.22 × 10 $ kg U, significantly lower than the previously reported materials. This work provides a highly efficient strategy for uranium extraction from water.