Highly efficient In–Mo(O,S)2 oxy-sulfide for degradation of organic pollutants under visible light irradiation: An example of photocatalyst on its dye selectivity

Abstract

Environmentally toxic organic pollutants, namely methylene blue (MB), neutral red (NR), Rhodamine B (RhB), and methyl orange (MO) dyes contain highly toxic, carcinogenic, non-biodegradable, and colored pigments which cause harm for humans and aquatic organisms even at low concentrations. To detoxify these toxic organic pollutants from the wastewater, the bimetallic solid solution-typed In–Mo(O,S)2 catalyst with various indium (In) contents were synthesized at low temperature through a simple precipitation method. The morphological, structural, chemical compositions, electrochemical and optical properties of the catalysts were thoroughly characterized. The photodegradation performance of the In–Mo(O,S)2 catalysts over the cationic, anionic and neutral dyes were studied under visible light irradiation. It has been observed that the photocatalytic activity was enhanced as In was added to the Mo(O,S)2 catalyst, and In–Mo(O,S)2-20 was found to be the best composition to completely degrade four organic dyes. The dye degradation had rate constant values of 9.5 × 10−2 min−1, 6.3 × 10−2 min−1, 4.4 × 10−2 min−1, and 15.7 × 10−1 min−1 for MB (20 ppm), NR (20 ppm), RhB (10 ppm), and MO (10 ppm) dyes, respectively. The active species for degradation of MB is different from those for RhB and MO. Single phase In–Mo(O,S)2-20 capable to degrade four kinds of dyes at a fast rate is a good photocatalyst.