Construction of a BaTiO3/tubular g-C3N4 dual piezoelectric photocatalyst with enhanced carrier separation for efficient degradation of tetracycline

One-dimensional tubular g-C3N4 (TCN) with piezoelectric properties was prepared by self-assembly and hydrothermal method, and BaTiO3/TCN composite with excellent dual piezoelectric properties was constructed by further hydrothermal reaction. The piezoelectric degradation rate of tetracycline hydrochloride (TCH) by TCN (18.2 %) within 60 min under ultrasonic vibration was about 2.8 times higher than that by bulk g-C3N4 (CN) (6.6 %). Furthermore, the BaTiO3/TCN composite, a dual piezoelectric photocatalyst, exhibited excellent piezoelectric photocatalytic activity with TCH degradation rate of 91.0 % within 60 min under visible light (VSL) illumination and ultrasonic vibration, which was higher than that of ultrasonic vibration (27.8 %) and VSL illumination (81.8 %). The polarization electric fields were formed in both TCN and BaTiO3 under ultrasonic vibration, which could maintain the built-in electric field strength between the heterojunction interfaces, accelerate the photogenerated carrier migration, and thus improve the separation efficiency to achieve the synergic catalytic effect of dual piezoelectric under VSL irradiation. This work demonstrated that TCN had better piezoelectric photocatalytic properties than CN, and the efficient pollutant removal performance of dual piezoelectric photocatalysis, which provided new ideas for the development of piezoelectric photocatalysts.