Two-dimension superstructure with Fe-based Mott-Schottky heterojunctions for highly efficient extraction of uranium

Uranium capture from aqueous solution is a hopeful project for the development of the nuclear industry, while the construction of adsorbents with high adsorption capacity, kinetics and selectivity remains a challenge. Herein, a feasible two-dimensional superstructure of Fe-based Mott-Schottky heterojunction (2D-Fe-N-C) is fabricated by an ice template and pyrolysis coupling strategy, which synergistically achieves the high-performance adsorption and reduction of UO₂²⁺ from aqueous solution. The two-dimensional superstructure exposes more active sites and promotes ion transport, thereby increasing the adsorption capacity and accelerating the adsorption rate of the material. In addition, the internal electric field generated by the work function difference formed by each component of heterojunction contributes to improving the conductivity and speeding up the charge transfer. Meanwhile, the resulting charge space at the heterogeneous interface enhances the adsorption of uranium and the reduction reaction. Thus, the designed 2D-Fe-N-C demonstrates excellent adsorption and reduction properties for uranium, with extraction efficiency reaching up to 1348 mg/g and achieving adsorption equilibrium within 4 h. Moreover, 2D-Fe-N-C demonstrates high selectivity for various ions and exhibits superior adsorption performance in real water systems. This research offers a feasible strategy based on the synergistic effects of superstructure and interface engineering to achieve highly efficient selective adsorption of uranium.