Oxygen vacancy-mediated piezocatalytic-driven H2O2 pathways for efficient uranium extraction

Efficient uranium extraction from wastewater is crucial for environmental protection and the sustainability of nuclear energy. Herein, we propose a novel uranium extraction strategy by integrating piezocatalysis and defect engineering, and elucidate the underlying interfacial mechanism. Oxygen-vacancy-rich ZnO (ZnO-OV) exhibits a 53% enhanced piezoelectric response, boosting U(Ⅵ) extraction efficiency by ∼34%with a high uranium uptake capacity of 904.17 mg g −1 . It also shows excellent durability, with only ∼0.7% efficiency loss after five adsorption–desorption cycles. Mechanistically, the superior performance of ZnO-OV arises from synergistic effects: oxygen vacancies facilitate polarization-induced charge separation and transfer, and provide abundant active sites for oxygen adsorption. Under ultrasonic stimulation, piezoelectric electrons from ZnO-OV directly reduce adsorbed UO 2 2+ species, trigger oxygen reduction and water oxidation to in situ generate H 2 O 2 , which reacts with UO 2 2+ and reduced UO 2 to form insoluble (UO 2 )O 2 ·2H 2 O for efficient uranium separation. This study reveals oxygen vacancies as pivotal active sites for oxygen adsorption and plays a determinant role in boosting piezocatalysis, offering fundamental insights into the rational design of defect-regulated piezocatalysts to promote interfacial redox reactions.