Dual conversion pathways for efficient electrochemical extraction of uranium

The electrochemical extraction of uranium (EEU) from wastewater is of promise to ensure the sustainable development of nuclear power, of which the practical application is limited due to the single uranium species conversion pathway. To overcome this problem, we have fabricated tungsten oxide/polypyrrole composites (W₁₈O₄₉/PPy) with tuned interface for double conversion pathways for EEU. The PPy has two functions: (1) to modulate the electronic structure of W₁₈O₄₉, resulting in a built-in electric field (BEF) that accelerates the reduction of uranium; (2) to form a conversion pathway, as the catalytic center for 2e⁻-ORR to produce H₂O₂ that directly reacts with UO₂²⁺ to form (UO₂)O₂·2H₂O. The W₁₈O₄₉/PPy electrodes shows a high extraction capacity of 3104.25 mg g^-1. With the W₁₈O₄₉/PPy as electrode, 15.75 mg of uranium was recovered from uranium-spiked groundwater in 16.7 hours. This work has paved a way to efficient electrochemical extraction of uranium enabled by double conversion pathways.