Internal piezoelectric field produced by tri-component (FTO: Sb-ZnO/MoS2) thin film for enhanced photocatalytic degradation of organic pollutants and antibacterial activity

Abstract

The detection of organic dyes, pharmaceuticals and microorganisms in the water environment continues to be a major concern worldwide. Hence, we report a novel method whereby a tri-component (Sb-ZnO/MoS2) immobilized on Fluorine-doped Tin Oxide (FTO) substrate for piezo-photocatalytic degradation of organic contaminants and bacterial disinfection. To determine the optical, electrochemical, physical and chemical properties of the Sb-ZnO/MoS2, the following methods were applied, SEM & EDS, TEM, XRD, BET, UV-Vis DRS, PL, EIS and chronoamperometry. The SEM and TEM results showed long ZnO nanorods on the surface of stacked MoS2 nanosheets. Chronoamperometry studies displayed that Sb-ZnO/MoS2 tri-component exhibited piezoelectric effect under ultrasonic vibration, indicating internal piezoelectric field for inhibition of electrons and holes from recombination. According to PL studies, Sb-ZnO/MoS2 tri-component had a lower PL emission peak intensity, which suggests a better separation of electrons and holes. The developed tri-component was investigated for its catalytic degradation of methylene blue (MB), methyl orange (MO) and ciprofloxacin (CIP) under light and ultrasonic vibration. The coupling of light (photocatalysis) and ultrasonic irradiation (piezocatalysis) showed greater degradation efficiencies of 95, 82 and 72% for MB, MO and CIP, respectively. The degree of mineralisation were recorded from total organic carbon (TOC) as 76, 70 and 52% for MB, MO and CIP, respectively. In addition, Sb-ZnO/MoS2 tri-component was shown to have antibacterial activity against both E. coli and S. aureus bacterial strains. Therefore, this study reveals that the prepared Sb-ZnO/MoS2 tri-component can be applied for simultaneous removal of dyes, pharmaceuticals and disinfection of wastewater pollutants.