Twisty C‐TiO2/PCN S‐Scheme Heterojunction with Enhanced n→π * Electronic Excitation for Promoted Piezo‐Photocatalytic Effect

Abstract Herein, a twisty C‐TiO 2 /PCN (CNT) Step‐scheme (S‐scheme) heterojunction is fabricated and applied to degrade ciprofloxacin (CIP) with the assistance of ultrasonic vibration and visible light irradiation. The nitrogen‐rich twisty polymeric carbon nitride (PCN) can not only induce a non‐centrosymmetric structure with enhanced polarity for a better piezoelectric effect but also provide abundant lone pair electrons to promote n→π* transition during photocatalysis. Its hybridization with C‐TiO 2 particles can construct S‐scheme heterojunction in CNT. During the piezo‐photocatalysis, the strain‐induced polarization electric field in the heterojunction can regulate the electron migration between the two components, resulting in a more effective CIP degradation. With the synergistic effect of ultrasonic vibration and visible light irradiation, the reaction rate constant of CIP degradation by CNT increases to 0.0517 min −1 , which is 1.86 times that of photocatalysis and 6.46 times that of ultrasound. This system exhibits a stable CIP decomposition efficiency under the interference of various environmental factors. In addition, the in‐depth investigation found that three pathways and 12 major intermediates with reduced toxicity are produced after the reaction. Hopefully, the construction of this twisty CNT S‐scheme heterojunction with enhanced piezo‐photocatalytic effect offers inspiration for the design of environmentally functional materials.