Self-regulated interfacial-enhanced piezo-phototronic effect of BNT@Mn-SnO2 heterostructures for superlative tetracycline degradation

Abstract

The piezo-promoted photocatalysis has recently been evolved as an auspicious technique to achieve high-efficiency and scalable organic pollutant degradation. Herein, a visible light active heterocomposite BNT@Mn-SnO2 (BSM) with plate-like Bi0.5Na0.5TiO3 (BNT) perovskite and Mn Nps decorated SnO2 was synthesized for the piezo-photocatalytic degradation of Tetracycline (TC). The piezo-photocatalytic degradation efficiency of TC reached 95.4% in 60 min, and the rate constant k reaches 0.078 min−1 which is 13 times and 2.8 times higher than the piezocatalytic and photocatalytic k values, individually. The meticulous built-in electric field regulation of BNT modified the band-gap structure and induced efficient charge separation in BSM nanocomposite. Furthermore, the plasmonic effect of the Mn Nps tuned the band-edge positions of SnO2 by introducing impurity energy levels and provided an alternative source of charge storage, and amplified the light absorption range of BSM nanocomposite. The oxidative species, particularly OH• played a substantial role in the piezo-photodegradation process than O2•- and 1O2. Besides, the toxicity evaluation revealed that the self-regulated interfacial-enhanced piezo-phototronic effect of BSM nanocomposite can deliberately reduce the ecotoxicity level into smaller and non-toxic compounds. This work provides a novel strategy to design efficient and sustainable piezo-photocatalysts for environmental remediation.