Facile synthesis of novel Ni-BDC-NH2/Au NPs SERS substrates with synergistic enhancement effects for high-performance detection

Abstract

Substrate materials with high sensitivity and good reproducibility are highly desirable for the practical applications of surface-enhanced Raman scattering (SERS) techniques. In this study, a novel gold nanoparticle-loaded Ni-based metal–organic framework (Ni-BDC-NH₂/Au NPs) SERS substrate was successfully synthesized via an electrostatic self-assembly method. The enhancement of the SERS signal is achieved owing to the synergy between the chemical enhancement (CM) effect of Ni-BDC-NH₂ and the electromagnetic enhancement (EM) of Au NPs, and the enriching of the analyte near the SERS “hot spots” through the strong adsorption capacity of Ni-BDC-NH₂. The Ni-BDC-NH₂/Au NPs exhibited a high enhancement factor (EF) of 1.10 × 10⁷ and a low detection limit of 5 × 10⁻⁹ mol L⁻¹. Besides, the substrate material showed exceptional stability for up to 45 days at room temperature. The Ni-BDC-NH₂/Au NPs was used to detect methylene blue (MB), displaying a wide linear range (5 × 10⁻⁷ to 5 × 10⁻⁵ mol L⁻¹) and high recoveries (86.82–104.46%). These results indicate that the Ni-BDC-NH₂/Au NPs hybrid substrate has great potential for the detection of environmental pollution in practical applications.