Fabrication of ZnO–TiO2 nanohybrids for rapid sunlight driven photodegradation of textile dyes and antibiotic residue molecules

Abstract

Abstract Semiconductor nanohybrids garner huge interest among environmentalists for the various applications owing to their efficiency, cost-effectiveness and benignity. We report the fabrication of TiO2 nanoparticles (TNPs) functionalized ZnO nanoflakes (ZNFs) and their outstanding detoxification ability towards the methylene blue (MB), rhodamine 6G (R6G) and Oxytetracycline (OTC) molecules solution in water. TEM studies confirm the formation of 3D architecture of ZnO–TiO2 nanohybrids while high-resolution transmission electron microscopy assures the uniform functionalization of TNPs over ZNFs. Scanning electron microscopy studies reveal the modulation in the surface morphology with the tenability in volume ratios of Zn and Ti sources. Significant PL quenching in ZnO–TiO2 nanohybrids spectrum as compared to ZNFs confirms the improvement in the charge separation which is highly favorable for the enhancement in the photodegradation efficiency. The 3D architecture of ZnO–TiO2 with volume ratio (Zn: Ti: 4:1) showed superior photodegradation activity and decompose OTC, MB and R6G dye solution within 8 min, 6 min and 30 min respectively under natural solar light (~862 W/cm2). Most efficient ZnO–TiO2 nanohybrid exhibits extremely high rate constant values for MB, R6G and OTC molecules which are 7, 5 and 4.8 times of the rate constant value of pure ZNFs. Extremely superior photodegradation performance of 3D architecture of ZnO–TiO2 nanohybrid could be ascribed to the charge separation and synergistic effect between the TNPs and ZNFs which is responsible for the high density of electrons in the conduction band of ZnO–TiO2 nanohybrids. ZnO–TiO2 nanohybrids reveal the extremely high photodegradation rate for the decomposition of azo dyes and pharmaceutical residue which has not been reported till now.