Functionalized Ag/MOF nanocomposites based on defect engineering for highly sensitive SERS detection of organic dyes

The utilization of Surface-Enhanced Raman Scattering (SERS) technology expedites the detection of Crystal Violet (CV), addressing its challenges of inefficiency and low sensitivity. To overcome these limitations, a MOF(Zr)@Ag NPs substrate was meticulously prepared through a "two-step" process for enhanced SERS detection. The Metal-Organic Framework (MOF) boasts a substantial specific surface area and high porosity, augmenting the formation of "hot spots" through Localized Surface Plasmon Resonance (LSPR) of Ag NPs and demonstrating commendable adsorption capabilities for CV. Within this investigation, we incorporated organic ligands with amino and sulfhydryl groups into the MOF structure. During the synthesis of MOF, the inclusion of benzoic acid plays a crucial role in diminishing the coordination number of metal nodes when combined with terephthalic acid. the heightened number of defect sites adeptly adsorbs signal molecules in SERS detection, resulting in reduced Raman signal detection limits. Empirical results substantiate the composite material's remarkably low SERS detection limits for dyes, including CV, Rhodamine 6 G (R6G), and 4-Mercaptobenzoic Acid (4-MBA). Additionally, it can identify CV residue at concentrations surpassing parts per billion in shrimp tissues. These observations propose the applicability of MOF(Zr)@Ag NPs for the swift and accurate detection of substance residues, encompassing CV, in shrimp specimens.