Harvesting the Vibration Energy of CdS for High‐Efficient Piezo‐Photocatalysis Removal of U(VI): Roles of Shape Dependent and Piezoelectric Polarization

Abstract

Piezo‐photocatalysis could coalesce the advantages of mechanical vibration and solar energy perfectly to achieve high‐efficiency catalytic activity. Herein, the quintessential piezoelectric material CdS nanowires with different aspect ratios are precisely constructed and applied for piezo‐photocatalytic reduction of U(VI) for the first time. The ultrasonic (60 kHz, 100 W) induces piezoelectric potential to generate a 0.57 eV A−1 electric field, which is added to the direction of CdS (010) as a driving force to efficiently separate photogenerated charges. The alliance between piezoelectric effect and photocatalytic activity endows CdS NW‐3 with the fastest piezo‐photocatalytic rate under ultrasonic vibration and 5 W LED irradiation, and the relevant rate constant (0.042 min−1) is about 12 and 53.8 times than that of LED and ultrasonication. More importantly, 93.74% of U(VI) could be removed from natural uranium mine wastewater. Therefore, this piezo‐photocatalysis system that reduces U(VI) to easily separable (UO2)O2·2H2O(s) provides valuable input for disposal applications of radioactive wastewater and broadens the horizons of nuclear energy utilization toward the advancement of carbon neutrality.