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

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.