Co0.5S/Pt nanoparticles: A novel photocatalyst for the degradation of methyl orange

Organic dyes released from the textile industry pose a serious threat to aquatic life. Semiconductor-based photocatalysis is an effective method for the treatment of industrial wastewater. Herein, a semiconductor-metal composite material, viz. Co 0.5 S/Pt nanoparticles (NPs), was synthesized and characterized by various analytical techniques. The photocatalytic activity of the Co 0.5 S/Pt NPs was evaluated by investigating the degradation of methyl orange using a tungsten halogen lamp emitting radiation in the 360–720 nm range. The absorption peak of the dye at 464 nm was found to diminish with increase in the irradiation time. The photocatalytic efficiency of the composite material was found to be 3.6 times higher than that of the Co 0.5 S NPs. The electrochemical impedance spectroscopy (EIS) measurements demonstrated significantly lower interfacial charge transfer resistance for the Co 0.5 S/Pt NPs in comparison to the Co 0.5 S NPs. The liquid chromatography-mass spectrometry (LC-MS) analysis established the formation of intermediate degradation products. The mechanistic studies revealed that the photogenerated hole was the primary reactive species involved in the degradation of methyl orange. The recyclability experiments showed that the Co 0.5 S/Pt NPs could be used up to three cycles. • Co 0.5 S/Pt NPs were characterized by various analytical techniques. • Co 0.5 S/Pt NPs had a 3.6-fold higher photocatalytic activity than the Co 0.5 S NPs. • The methyl orange molecules were oxidized by the VB holes. • LC-MS measurements suggested intermediated degradations products of the dye.