Nitrogen and sulfur co-doped reduced graphene oxide (rGO)/gold nanoparticles hybrids for SERS sensing platform

Detection of organic pollutants in water and food is essential to resolve environmental issues and ensure the sustainable growth of society. Surface Enhanced Raman Spectroscopy (SERS) has emerged as a superlative technique to detect these pollutants that are present even in trace amounts (ppb, parts per billion, and smaller), but the substrate fabrication is intricate. Herein, we have developed novel substrates based on graphene oxide (GO), specifically co-doped with Nitrogen and sulfur (NS-rGO) and decorated with Au NPs through a wet chemical route. TEM analysis demonstrates that spherical shape Au NPs of 14.5 +/- 3 nm size are uniformly distributed on the NS-rGO surface. The developed SERS substrate is used to detect Rhodamine 6 G (Rh-6 G) and Methylene Blue (MB) dye, organic pollutants. The interaction of Au NPs with the thiol group and the synergistic effect of Au NPs and nanohybrids could be the possible reason for obtaining 9 order enhancement factor, wide linear range, and a limit of detection up to Pico molar. Furthermore, the prepared substrate exhibited good uniformity and reproducibility. We have also demonstrated the competence of substrate by testing water spiked Rh-6 G with good reproducibility for onsite detection of organic pollutants.