Magnetic nanoporous carbon-based self-enriched and self-cleaning recyclable substrate Co/C@Ag/g-C3N4 for SERS detection and photocatalytic degradation of malachite green

This study reports the design and fabrication of a magnetic nanoporous carbon-based recyclable surface-enhanced Raman scattering (SERS) substrate Co/C@Ag/g-C₃N₄, which can simultaneously achieve SERS detection and visible-light photocatalytic degradation of malachite green (MG). Co/C and g-C₃N₄ can spontaneously adsorb and concentrate MG near plasmonic nanoparticles, thereby enhancing the SERS response. The substrate exhibited a SERS enhancement factor of approximately 1.3 × 10⁶. The limit of detection (LOD) for MG in aquaculture water, prawn, and tilapia was 8.2 × 10⁻¹¹ M, 0.08 μg/kg, and 0.06 μg/kg, respectively. The substrate can be magnetically collected from the complex matrix and regenerated through photocatalytic degradation. Eliminates the co-centrifugation of the SERS substrate with the complex matrix. Even after 4 regeneration cycles, the substrate retained nearly 80 % of its original SERS intensity. This study presents a novel strategy for constructing self-enriched, self-cleaning, and recyclable substrates with promising applications in food safety and environmental protection.