Acceleration of Singlet Oxygen Evolution by Sonopiezoelectric Charge Transfer Over SrTiO ₃ ‐TiO ₂ Heterojunction for Selective Oxidation

ABSTRACT Sonopiezo‐mediated heterogeneous catalysis is a promising technology for efficient removal of organic pollutants from wastewater. Nevertheless, it is challenging in real water matrix with coexisting ions due to the rather‐limited selectivity of reactive oxygen species if any. Herein, a sonopiezo‐triggered singlet oxygen evolution system for selective removal of tetracycline hydrochloride (TCH) was rationally designed by SrTiO 3 ‐TiO 2 heterojunction with a TiO 2 ‐terminated SrTiO 3 S‐scheme interfacial structure. SrTiO 3 ‐TiO 2 heterojunction exhibits a dramatically expanded piezoelectric constant ( d 33 ), which produces a synergistic effect on improving the separation and transfer efficiency of charge carrier for efficient TCH degradation. Moreover, SrTiO 3 ‐TiO 2 heterojunction presents a high sonopiezo‐current, which attractively indicates that SrTiO 3 ‐TiO 2 heterojunction has a potential capacity of charge separation under sonopiezo initiation. Remarkably, the mechanism was identified as the continuous generating of singlet oxygen ( 1 O 2 ), in which the sonopiezo‐generated electrons trigger the formation of superoxide anion radical (•O 2 − ) and its subsequent transformation to generate 1 O 2 by expending more sonopiezo‐generated holes. These findings provided new insights towards developing nonradical system for effective and selective oxidation of electron‐rich pollutants via sonopiezo‐catalytic process.