Amino-engineered plasmonic Schottky junctions: recyclable H-CN/AgNPs for integrated SERS detection and degradation of trace organic dyes.

Rapid detection and effective catalytic degradation of dyes in wastewater are crucial for safeguarding environmental aquatic ecosystems and human health. Herein, we designed and fabricated a dual-functional composite of amino-rich graphitic carbon nitride combined with silver nanoparticles (H-CN/AgNPs), serving as both reusable surface-enhanced Raman scattering (SERS) substrate for sensitive detection and as a photocatalyst for efficient degradation of organic dyes. The synergistic effects of electromagnetic enhancement of plasmonic AgNPs and the chemical enhancement mechanisms of H-CN endowed the H-CN/AgNPs exceptional SERS performance. For crystal violet (CV) as a model analyte, it demonstrated high detection sensitivity with a detection limit (LOD) of 6.33 × 10⁻ M. Both the improved charge carrier separation resulting from higher amino group density and the Schottky effect arising from the metal-semiconductor junction contributed to the enhanced photocatalytic efficiency. Methylene blue (MB) was degraded by 99.2% within 8 min under visible-light illumination, demonstrating rapid photocatalytic activity. Notably, the SERS sensitivity and recyclability of H-CN/Ag are preserved after four cycles, facilitating a synergistic 'detection-degradation-recycling' process for organic pollutants, which highlights its utility in environmental monitoring and pollution control.