Piezo-Photocatalytic Degradation of Tetracycline by 3D BaTiO3 Nanomaterials: The Effect of Crystal Structure and Catalyst Loadings

Piezoelectric photocatalysis improves catalytic activity by preventing photogenerated carrier recombination. Hence, three morphologies of BaTiO3 (BTO) were successfully prepared for the piezoelectric photocatalytic degradation of tetracycline (TC, C(TC) = 40 mg/L). The tetragonal-phase BaTiO3 nanoparticles (BTO-NPs) showed the best performance in comparison with cubic-phase nanoflowers (BTO-Nf) and cubic-phase coral-like structures (BTO-Nc) under the same conditions (C(BTO) = 0.6 g/L). When the loading of BTO-NPs was reduced to 0.2 g/L, the photocatalytic degradation efficiency was lowered from 64.2% to 50.1%. However, the 0.6 g/L BTO-NPs increased by only 12.8% after piezoelectricity induction. On the contrary, the BTO-NPs’ degradation effect of 0.2 g/L with the piezoelectric effect was greatly improved from 50.1% to 78.0%, with an increase rate of 27.9%. As the quantity of catalyst was decreased, the increased inter-particle voids made the lattice more susceptible to deformation by external forces, producing a more pronounced piezoelectric effect. These findings indicate that crystal structure and catalyst loading are critical factors in increasing piezoelectric photocatalytic performance. This article emphasizes the application value of piezoelectric photocatalysis in degrading organic pollutants, and provides practical guidelines for optimizing its performance.