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Here, we report a new and facile method to prepare silver nanoparticles (Ag NPs) film for surface-enhanced Raman scattering (SERS)-based sensing. The porous Ni foam was used as a template to generate high quality of Ag NPs by seed-mediated growth of metallic nanoparticles. The preparation process is very economic and environment-friendly, can achieve the recovery of the raw materials. We found that the type of silver-plating solution and the growth time are two key factors to determine the magnitude of SERS signal enhancement. Using rhodamine 6G (R6G) and 4-animothiophenol (4-ATP) as probe molecules, the created Ag NP films exhibited relatively high enhancement ability, good stability, and well reproducibility. The synthesized SERS-active substrate was further used to detect melamine molecules, an illegal additive in infant milk powder, and the limitation of detection can reach 1 μM.

An effective approach to attach gold nanoparticles (AuNPs) directly on indium tin oxide (ITO) surface with higher density is reported. The attachment was carried out using a cast seed-mediated growth method, which was revised from our previous seed-mediated growth approach. The cast seeding with three-cycles of the drop of the seed solution containing Au nano-seed particles and the evaporation at 30 °C followed by the treatment in the growth solution containing HAuCl 4 , cetyltrimethylammonium bromide (CTAB) and ascorbic acid was found to be suitable to prepare the AuNPs attached ITO surfaces having higher density and narrower size distribution. The 10-cycles cast seeding formed the connected or networked nanostructures of AuNPs, though the optical properties were different from those of the dispersed AuNP-attached ITO. The present cast seeding approach provides a facile and useful strategy to attach AuNPs on the surface without the use of certain organic binder molecules.