Preparation of NaNbO3-Based Piezocatalysts via Solid-State Method and Piezocatalytic Degradation of Organic Pollutants

Piezoelectric catalysis exploits the piezoelectric effect of materials under mechanical stress, inducing surface charges that participate in wastewater degradation reactions. This process generates no secondary pollution and represents an environmentally friendly, novel degradation technique. In this work, (0.92 − x)NaNbO3–0.08BaTiO3–xBiFeO3 piezoelectric powders were synthesized via a solid-state method. Ultrasonic waves were employed as the mechanical driving force, and the degradation of organic pollutants by piezoelectric catalysis was investigated. The results show that the NN-based powders and ceramics exhibit multiphase structures. The degradation efficiency of Rhodamine B (RhB) reached 88.11% within 80 min. Upon application of an external magnetic field, the degradation rate was enhanced. Furthermore, the piezoelectric catalytic powder demonstrated excellent cycling stability. Active species trapping experiments identified •OH and •O2− as the dominant reactive species. Instead of the conventional approach of preparing piezoelectric ceramics followed by crushing, this study directly produces NaNbO3-based piezoelectric powders using a solid-state method. The applied magnetic field may assist charge separation during piezocatalysis, offering a new route for the piezoelectric catalytic degradation of organic compounds.