d-Band modulation-induced self-regenerating SERS substrates for aromatic pollutant detection

Aromatic organic pollutants pose severe risks to aquatic ecosystems and call for analytical strategies that couple trace-level detection with efficient in situ degradation. Here, we report a plasmonic nanozyme composed of Ag nanoparticles on metal-organic framework-derived Fe 2 P (Ag@Fe 2 P/C), in which the Ag-Fe 2 P heterointerface integrates surface-enhanced Raman scattering (SERS) sensing with Fenton-like oxidation. Ag@Fe 2 P/C enabled ultrasensitive, quantitative SERS detection of crystal violet, 4-nitrophenol, and bisphenol A, with limits of detection of 10⁻ 10 –10⁻ 8 M, correlation coefficients R 2 above 0.95, and relative standard deviations below 5%. Under mild H 2 O 2 treatment, Ag@Fe 2 P/C completely degraded crystal violet within 10 min and 4-nitrophenol and bisphenol A within 30 min, and fully recovered its initial SERS response over six regeneration cycles. Density functional theory calculations show that the Ag-Fe 2 P heterointerface shifts the d band of Fe sites and enhances interfacial electron transfer, which in turn accelerates the Fe 2 ⁺/Fe 3 ⁺ redox cycle and promotes H 2 O 2 activation into hydroxyl radicals that remove adsorbed pollutants and regenerate SERS-active sites. By bridging plasmonic enhancement with enzyme-mimetic catalysis through interface engineering, this work provides a promising strategy to enable in situ SERS monitoring and degradation of representative aromatic organic pollutants.