Fabrication of novel S-type In2S3/Ag2S heterostructures with superior photocatalytic and electrochemical characteristics for remediation of organic contaminants in water

Abstract

In the present report, In₂S₃/Ag₂S heterojunctions were created hydrothermally and characterized for their crystalline structure, morphology, composition, optical characteristics, charges reunification and property of charge by standard analytical techniques. Synthesized nanomaterials were utilized for the decontamination of organic pollutants such as Rhodamine B (RhB) dye and antibiotic ciprofloxacin (CP) by using visible light radiance. Calculated photocatalytic removal efficacy for RhB and CP over In₂S₃/Ag₂S nanocomposite was 99.95 % in 40 min and 99.49 % in 140 min respectively which is 1.98 and 1.21 times greater than In₂S₃ alone. Maximum removal efficiency was achieved for In₂S₃/Ag₂S (3 wt%) composition. The enhanced activity is attributed to the greater absorption of visible light and construction of S-type heterojunction which are more efficient for light induced charge separation and therefore decrease the reunification of hole-electron carriers. Density functional theory (DFT) analysis also supported that the nanocomposite is energetically favorable, stable and show significantly electronic and photocatalytic properties. In₂S₃/Ag₂S (3 wt%) nanocomposite achieved excellent photocatalytic stability towards the removal of RhB and CP even after five runs. In₂S₃/Ag₂S (3 wt%) nanocomposites showed maximum photocatalytic activity in acidic medium. Effect of trapping agents towards removal of CP and RhB were conducted and results showed that^.O₂⁻ radical play dominant role as active species in comparison to ⋅OH radical and holes. Plausible mechanism of transfer of charge in In₂S₃/Ag₂S and removal of pollutants is also represented. Owing to their unique features, novel In₂S₃/Ag₂S heterojunctions exhibits as an exceptionally effective photocatalyst for removal of pollutants and it would display the promising utilization towards wastewater treatment.