Piezo-photocatalytic activity of NaNbO3/g-C3N4 heterojunction for dye wastewater degradation

The recombination of charge carriers in photocatalysts is one of the main factors restricting photocatalytic performance. In this paper, the NaNbO 3 /g-C 3 N 4 heterojunction photocatalyst was prepared by a simple ultrasonic mixing approach and applied to obtain superior piezo-photocatalytic activity. The results showed that the NaNbO 3 nanowires were attached to the g-C 3 N 4 surface for efficient degradation of rhodamine B (RhB). Through the synergistic action of visible-light irradiation and ultrasonic vibration, the RhB solution could be degraded within 30 min by 5% NaNbO 3 /g-C 3 N 4 heterojunction. The reaction rate constant ( k ) of 5% NaNbO 3 /g-C 3 N 4 heterojunction is 2.7 times that of pure g-C 3 N 4 . Moreover, quenching tests and electronic spin resonance (ESR) indicated that ·O 2 − was the primary active species for RhB degradation. The enhanced photocatalytic performance was attributed to the formation of the heterojunction at the NaNbO 3 /g-C 3 N 4 interface. Furthermore, the piezoelectric field that originated from the bending deformation of NaNbO 3 nanowires effectively promoted charge carriers separation efficiency in the NaNbO 3 /g-C 3 N 4 heterojunction.