Synthesis and characterization of g-C3N4 nanosheets decorated Ag2S composites for investigation of catalytic reduction of 4-nitrophenol, antioxidant and antimicrobial activities

A one-pot sonochemical process was used for the synthesis of cost-effective g-C3N4 nanosheets decorated Ag2S composite catalysts and characterized by various techniques. Furthermore, the UV-vis spectroscopy was used to monitor the catalytic reduction of 4-NP in the presence of g-C3N4/Ag2S composite with an excess of NaBH4. The g-C3N4/Ag2S composite exhibited higher catalytic activity toward the reduction of 4-NP than the pure g-C3N4 and Ag2S. In addition, the upward shift of the energy band of g-C3N4 due to the location of Ag2S led to stronger reducibility of charge carriers. As a consequence, the catalytic performance of g-C3N4/Ag2S has been remarkably improved in the catalytic reduction of 4-NP and exhibited excellent stability up to 5 cycles. The effect of NaBH4 concentration was also investigated for the reduction of 4-NP using g-C3N4/Ag2S composite. The scavenging radicals from the antioxidant activity of the synthesized composites were determined by DPPH method. In addition, the synthesized composites showed good antimicrobial activities using paper disc method. The results indicate that the synthesized g-C3N4/Ag2S composite exhibits superior catalytic, antioxidant and antimicrobial activities and potential applications in near future in the field of biomedicine, wastewater treatment for purification and nanobiotechnology. (C) 2019 Elsevier B.V. All rights reserved.