A hydrophilic–hydrophobic graphitic carbon nitride@silver hybrid substrate for recyclable surface-enhanced Raman scattering-based detection without the coffee-ring effect

Abstract

There is growing interest in developing a multifunctional surface-enhanced Raman scattering (SERS) substrate to deal with the challenge in the pretreatment-free detection and degradation of hazardous organic pollutants in water. Herein, a hydrophilic–hydrophobic graphitic carbon nitride@silver (g-C₃N₄@Ag) hybrid substrate was exploited as a potential candidate for the recyclable detection of dye molecules. Such a sophisticated substrate not only showed a significant SERS activity with a high enhancement factor of 3.21 × 10⁶ triggered by the significantly aggregated Ag nanoparticles, but also possessed an outstanding self-cleaning property via visible-light irradiation. Furthermore, the effective weakening of the coffee-ring effect was also facilitated by the hydrophilic–hydrophobic structure, resulting in excellent uniformity and reproducibility. Ultimately, the applicability of the developed recyclable SERS substrate in the monitoring of trace malachite green was demonstrated. It is expected that the innovative SERS substrate has great potential for application in highly sensitive, stable, and recyclable on-site analysis, especially for organic pollutant treatment and environmental protection.