Functionalized Silver Nanocubes for the Detection of Hazardous Analytes through Surface-Enhanced Raman Scattering: Experimental and Computational Studies

Abstract

The functionalization of nanomaterials offers a significant impact on environmental protection. Three silver composites, silver nanocubes (Ag NCs) with cellulose (Ag-CE), Ag NCs with chitosan (Ag-CH), and Ag NCs with neutral alumina (Ag-NA), were synthesized with the incorporation of a very low concentration of Ag NCs. The synthesized Ag-composites were used for the detection of hazardous analytes, 4-mercaptobenzoic acid (4-MBA), rhodamine 6G (R6G), and methylene blue (MB), via a highly sensitive surface-enhanced Raman scattering (SERS) technique. The enhancement factors for the detection of MB were found to be 1.2 × 106, 1.4 × 106, and 3.7 × 105 using Ag-CE, Ag-CH, and Ag-NA, respectively. Limits of detection of 1 nM, 100 pM, and 100 μM were achieved for MB using Ag-CE, Ag-CH, and Ag-NA, respectively. The Ag-CH composite achieved excellent sensitivity and enhancement for the detection of MB compared to the other two Ag-composites. The order of detection efficiency of MB using Ag-composites was measured theoretically and follows the order Ag-CH > Ag-CE > Ag-NA. A real-time filtration unit showed excellent efficiency for MB removal. The present method can be employed in commercial filtration processes for the benefit of the environment and sustainable development.

A Three-Dimensional Hydrophobic Surface-Enhanced Raman Scattering Sensor via a Silver-Coated Polytetrafluoroethylene Membrane for the Direct Trace Detection of Molecules in Water

“…Localized surface plasmon resonance (LSPR) is the basic physics for SERS, where hotspots as strongly enhanced photoelectric fields locally generated on metallic nanostructures [7][8][9][10]. LSPR performance can be precisely controlled by designing metallic nanostructures of different sizes [11,12], different shapes [13,14], and different materials [15,16]. Although there are extensive reports on the design and realization of SERS substrates in different forms, there are always increasing demands for sensors with more versatile utility and more general applications.…”