Development of superhydrophilic ZnOX/TiO2 with visible light-induced self-cleaning and antibacterial properties

Abstract

Many studies aimed to improve the antibacterial ability and applicability of antibacterial surface materials by altering their chemical composition and structure. In this study, we successfully prepared a multifunctional ZnOX/TiO2 (0<X ≤ 2) nanocomposites by a sol-gel method, which exhibits visible light responsive self-cleaning, antibacterial adhesion, and antimicrobial properties. In the comparison of the three zinc sources, it was found that the ZnOX/TiO2 prepared with zinc sulfate doping had a water contact angle of only 1.7°, with enhanced hydrophilicity, and exhibited the best photocatalytic activity under visible light, with a removal rate of up to 90.2% of methylene orange (MO). Antibacterial tests revealed the average diameters of the inhibition halos for Escherichia coli and Staphylococcus aureus were 10 and 12 mm, respectively, thereby showing excellent antibacterial activity under visible light. The low photogenerated electron-hole recombination and the high rates of ·OH and ·O2- generation through photo-induced interface charge transfer in ZnOX/TiO2 composite, which is the main reason for enhancing the photocatalytic antibacterial activity under visible light irradiation. Release of Zn2+ species, resulting in significant antibacterial performance even under dark conditions. This study combines doping and surface modification, introduce abundant surface hydroxyl groups to endow the composite material surface with superhydrophilicity, anti-bacterial adhesion, and antibacterial properties that can meet the needs of clean and antibacterial surfaces in medical.