Graphene boosted silver nanoparticles as surface enhanced Raman spectroscopic sensors and photocatalysts for removal of standard and industrial dye contaminants

Abstract Uncontrolled volumes of textile effluents (TE) discharged into water-bodies significantly escalate the possibility of health hazards and environmental deterioration owing to the presence of hazardous dye contaminants. In this work, the toxic components in real TE were sensed on a graphene boosted silver nanoparticles (Ag-rGO) platform through surface enhanced Raman scattering (SERS) technique. Transmission electron microscopic images of Ag-rGO showed spherical Ag nanoparticles of ∼8 nm dispersed on wrinkled graphene oxide sheets. The efficiency of the substrate as a SERS sensor and photocatalytic substrate was first analyzed on commercial dyes such as rhodamine6 G, Congo red and malachite green. In TE, carcinogenic azo dye contaminants were effectively identified from the presence of N N and C N bands present in the SERS spectra. Further, removal of these dye contaminants in TE through visible light assisted photocatalysis by Ag-rGO was also evaluated. High degradation rate constant of ∼9 × 10 −3 /min was observed in TE after visible light assisted photocatalysis by Ag-rGO. Synergistically, the dual utility of Ag-rGO can be attributed to the enhanced electromagnetic field originating from the plasmonic nature of Ag nanoparticles and the strengthened charge transfer due to the adsorptive nature of rGO. Furthermore, the reduced particle size and suppressed fluorescence also aids the sensing and removal. These results suggest feasible development of sensitive, scalable, stable intermediate dye sensing and removal/ water recycling structures based on Ag-rGO to be incorporated at the discharge stage of textile dyeing industries.