Photocatalytic Performance of SnO2:Mo Nanopowders Against the Degradation of Methyl Orange and Rhodamine B Dyes Under Visible Light Irradiation

Abstract

Visible light-mediated photocatalytic performance of the Mo-doped SnO2 (SnO2:Mo) nanopowders synthesized via cost-effective chemical method against methyl orange (MO) and rhodamine B (RhB) dyes has been outlined in this paper. Mo concentration in SnO2 is varied as 0 wt.%, 5 wt.%, 10 wt.% and 15 wt.%. The nanopowders were characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, diffuse reflectance spectra and photoluminescence. The (1 0 1) preferential growth observed for the undoped SnO2 is retained for all the doped samples. Uniform distribution of grains was observed from the SEM images of all the samples with grain size being reduced with Mo doping. XPS spectrum of the 10 wt.% Mo-doped sample confirmed that Sn and Mo exist in +4 and +6 oxidation states, respectively. The band gap of pure SnO2 decreased from 3.56 eV to 3.44 eV with Mo doping. Photocatalytic performance of pure SnO2 got enhanced with Mo doping and the 10 wt.% Mo-doped SnO2 sample exhibited maximum degradation efficiency of 90.23% against MO and 81.14% against RhB dyes. The results confirm that the SnO2:Mo nanopowders are well suited as an efficient catalyst for degrading organic dyes in waste water.