Development of niobium doped tin oxide nanostructure via hydrothermal route for photocatalytic degradation of methylene blue and antimicrobial study

Abstract

In this work, we discuss the effect of niobium (Nb) doping concentrations of 2% and 4% on the physicochemical characteristics and photocatalytic properties of tin dioxide nanostructure, which were successfully developed by a basic hydrothermal route. Nb-doped SnO2 were characterized with regards to their optical, structural and photocatalytic features. X-ray diffraction (XRD) analyses display that both pristine and doped tin dioxide had a fine crystalline structure having tetragonal structure. Scanning electron microscopy (SEM) analysis shows that materials exhibited the irregular shaped nanoparticles morphology. Optical absorption analysis using UV–visible spectroscopy revealed a redshift in the bandgap energy for Nb3+ doped SnO2 nanoparticles. Methylene blue aqueous (MB) dye was degraded by 93.78% in 120 min when exposed to 4% Nb doped SnO2 NPs under visible light. The 4% Nb doped SnO2 shows elevated photocatalytic activity owing to their greater surface area containing greater active zones responsible for adsorption of larger dye species and good structural stability. Similarly, the 4% Nb doped SnO2 photocatalysts maintained their excellent stability and photodegradation efficiency over 89% even after being subjected to 5th cycles. The scavenger analysis demonstrates that the superoxide (O2) radical, a major active substance, performed a crucial role in the mineralization of the aqueous MB dye. The 4% Nb doped SnO2 also shows remarkable antimicrobial activity. Our finding suggests that doping strategy considered as efficient method that can help to increase the photocatalytic and antimicrobial activity.