An efficient photocatalytic degradation of organic dyes under visible light using zinc stannate (Zn2SnO4) nanorods prepared by microwave irradiation

Abstract

Ternary compounds are found to be more thermally stable with high electron mobility and hence higher efficiency towards sensing, photocatalysis and optoelectronic devices as compared to binary compounds (ZnO, SnO2). An elegant approach was made to synthesis one dimensional zinc stannate (Zn2SnO4) using microwave technique, which is energy efficient, less time consuming and economically viable for large scale production. The cubic spinel structure was confirmed using X-ray diffraction (XRD) and rod shaped morphology was observed on field emission scanning electron microscope (FESEM). Nanorods obtained were pure, monodispersed and uniform. Structural composition, oxidation state and binding energy were studied using X-ray photoelectron spectroscopy (XPS). Optical properties were studied using UV–Vis and photoluminescence (PL) spectroscopy. Band gap was found to be 3.74 eV, which shows quantum confinement and was calculated using Tauc’s equation. Moreover, the growth mechanism is discussed with role of microwave radiation over conventional heating methods. Under visible light irradiation, Zn2SnO4 nanorods have excellent photocatalytic activity for the degradation of cationic rhodamine dye (60 mins, 98%) and anionic methyl orange dye (75 min, 82%), respectively. Even at fifth cycle Zn2SnO4 shows 92% efficiency.