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 NaNbO3/g-C3N4 heterojunction photocatalyst was prepared by a simple ultrasonic mixing approach and applied to obtain superior piezo-photocatalytic activity. The results showed that the NaNbO3 nanowires were attached to the g-C3N4 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% NaNbO3/g-C3N4 heterojunction. The reaction rate constant (k) of 5% NaNbO3/g-C3N4 heterojunction is 2.7 times that of pure g-C3N4. Moreover, quenching tests and electronic spin resonance (ESR) indicated that center dot O-2(-) was the primary active species for RhB degradation. The enhanced photocatalytic performance was attributed to the formation of the heterojunction at the NaNbO3/g-C3N4 interface. Furthermore, the piezoelectric field that originated from the bending deformation of NaNbO3 nanowires effectively promoted charge carriers separation efficiency in the NaNbO3/g-C3N4 heterojunction.

Automated summary

In this study, a NaNbO3/g-C3N4 heterojunction photocatalyst was prepared and applied for efficient piezo-photocatalysis. The attachment of NaNbO3 nanowires to the g-C3N4 surface facilitated the degradation of rhodamine B by visible-light irradiation and ultrasonic vibration. The NaNbO3/g-C3N4 heterojunction exhibited a higher reaction rate constant and the primary active species for rhodamine B degradation was identified as center dot O-2(-). The enhanced performance was attributed to the formation of the heterojunction and the piezoelectric field of NaNbO3 nanowires promoting charge carriers separation efficiency.