A highly sensitive Ni-Ag/GO SERS platform constructed for rapid detection of organic pollutants in environmental systems.

Abstract

Surface-enhanced Raman scattering (SERS) is a powerful spectroscopic technique, and the development of high-performance substrates is essential for achieving ultrasensitive molecular detection. Herein, a Ni-modified Ag/graphene oxide (Ni-Ag/GO) was successfully synthesized. The effects of GO content and Ag+ concentration on the SERS performance of the composite were systematically investigated. The outstanding SERS activity of the Ni-Ag/GO substrate is attributed to the synergistic contributions of the electromagnetic enhancement generated by Ag NPs, the molecular enrichment and charge-transfer effects of GO, and the interfacial electronic modulation induced by Ni. Using rhodamine 6G (R6G) as the probe molecule, the substrate exhibited excellent sensitivity with an ultralow limit of detection (LOD) of 2.35 × 10-14 M. The substrate also showed high signal uniformity, with a calculated relative standard deviation (RSD) of 8.52% and retained 90.34% SERS activity after four months of storage, demonstrating good long-term stability. Furthermore, the substrate was also successfully applied to the detection of methyl blue (MeB), malachite green (MG), and fenvalerate (FV), with calculated LODs of 1.21 × 10-11, 2.58 × 10-11, and 8.47 × 10-15 M, respectively. In real-sample analyses, the substrate achieved satisfactory recoveries of 98.12%-107.3% for MeB, 98.0%-107.1% for MG, and 95.70%-105.5% for FV, demonstrating reliable analytical performance. In addition, the Ni-Ag/GO composite showed excellent catalytic activity toward sodium borohydride (NaBH4) assisted degradation of MeB. Therefore, this work provides a viable strategy for developing multifunctional SERS substrates that integrate ultrasensitive molecular detection with catalytic degradation of organic pollutants for environmental applications.

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