Growth of size-controllable tetragonal rutile stannic oxide nanostructures by co-precipitation route for eosin Y dye degradation under solar radiation

Abstract

A simple one step co-precipitation route was employed to synthesize the size controlled quantum dots (size ~ 3 nm) by maintaining the pH value at 6, without addition of capping agent. The effect of different annealing temperatures on the structural and optical properties of as synthesized sample have been explained. XRD analysis of sample showed the formation of pure rutile SnO2 quantum dots with tetragonal rutile structure for all the prepared samples. The SnO2 sample prepared by co-precipitation route was annealed at different temperatures and photo catalytic activities of annealed samples at various temperatures were investigated under direct solar irradiation. The obtained prepared sample with smallest size (3 nm) annealed at 300 °C displayed excellent degradation of Eosin Y (EY) dye. This is attributed to small grain size, tuned band gap, high crystallinity and high interfacial surface area. Quantum confinement effect enhanced the catalyst performance by creating oxygen vacancies and enabling the efficient charge transportation through discrete energy levels. Synthesized samples of SnO2 was subjected to the photocatalysis experiment to determine their photodegradation efficiency and was found to be lower for annealed samples than that shown by SnO2 quantum dots. QDs showed 73% degradation efficiency for EY dye when illuminated under sunlight for an hour.