Mitigating Piezoelectric Screening Effect Via ZnO@ZnSe Core-Shell Heterojunction for Efficient H₂O₂-Mediated...

The sustainable expansion of nuclear power hinges on securing uranium supply and managing radioactive wastewater, yet conventional recovery methods suffer from low capacity, poor selectivity, and sluggish kinetics. Piezocatalysis offers a promising alternative, but its efficacy in single-phase materials is restricted by the piezoelectric screening effect. Herein, we construct a zinc oxide@zinc selenide (ZnO@ZnSe) heterojunction as a high-performance piezocatalyst for ultrasound-stimulated uranium recovery. A spontaneous interfacial built-in electric field with a ZnO-to-ZnSe orientation is established at the heterojunction, which actively mitigates the potential screening effect and amplifies the piezoelectric polarization. Consequently, the optimized ZnO@ZnSe-10 delivers an excellent uranium uptake capacity of 1372.7 mg·g^-1, high extraction selectivity, and good cycling stability. Mechanistic investigations elucidate a hydrogen peroxide (H₂O₂)-mediated piezocatalytic cascade: piezoelectrons convert dissolved oxygen (O₂) to superoxide radicals (•O₂ ^-), whose disproportionation generates in situ H₂O₂ that oxidatively precipitates soluble hexavalent uranyl ions (UO₂ ²⁺) as insoluble crystalline uranyl peroxide hydrates ((UO₂)O₂·2H₂O and UO₃·2H₂O). Density functional theory (DFT) calculations further confirm that the interfacial electric field lowers the thermodynamic barrier for key oxygen-containing intermediates, thereby promoting sustained H₂O₂ production for uranium recovery. This work establishes a general strategy to overcome the piezoelectric screening effect, providing a feasible strategy for high-efficiency uranium extraction.