Reusable and self-calibrating SERS platform with Ag-incorporated Prussian blue for efficient detection and degradation of organic pollutants

A reusable and self-calibrating Surface-Enhanced Raman Spectroscopy (SERS) substrate was developed for reliable detection and degradation of organic pollutants in complex environments. The substrate was fabricated by synthesizing Prussian blue (PB)-functionalized cotton (Cotton/PB), followed by Ag⁺ ion exchange with Fe³⁺ in the surface-bound PB and in situ reduction to form silver nanoparticles (Ag NPs). PB serves as an internal standard (IS) to correct SERS signal fluctuations and enables self-cleaning via photo-Fenton catalysis. The substrate exhibited high sensitivity, with detection limits for crystal violet (CV), rhodamine 6G (R6G), and malachite green (MG) of 4.6 × 10^-11 M, 9.2 × 10^-12 M, and 4.7 × 10^-11 M, respectively. IS calibration significantly improved quantitative precision, reducing the substrate uniformity relative standard deviation (RSD) from 13.59 % to 4.15 % and reproducibility RSD from 15.17 % to 3.33 %. Additionally, the substrate exhibited outstanding photo-Fenton degradation performance for R6G, achieving a 99 % removal rate within 120 min. The in situ growth of Ag NPs on the PB surface enhanced the photo-Fenton activity, increasing the rate constant of the Cotton/PB-Ag substrate by 2.1 times compared to Cotton/PB. Importantly, the platform maintained remarkable performance with a low RSD of 2.45 % after seven reuse cycles. This work offers a promising strategy for the consistent and precise detection of organic contaminants in environmental monitoring applications.