Metallic Cu nanoparticles dispersed into porous glass: A simple green chemistry approach to prepare SERS substrates

• Preparation of metallic copper nanoparticles on porous glass for SERS applications.
• Simple green chemistry approach to prepare SERS substrates.
• A highly effective SERS substrate based on Cu nanoparticles.

Metallic copper nanoparticles were prepared on Porous Vycor Glass (PVG) by impregnation of Cu2+ ions within the PVG porous structure, followed by reduction using sodium borohydride. This method is a free-carbon procedure, simple sample preparation procedure, and leads to formation of dispersed Cu nanoparticles inside PVG porous structure. The average size of the Cu nanoparticles was estimated by Transmission Electron Microscopy to be 4.6 nm. The substrate is based on porous glass template with pore size distribution between 2 and 20 nm. As PVG is a mesoporous material, molecules can diffuse within the pores and be adsorbed on Cu nanoparticles. The samples were applied as Surface Enhanced Raman Scattering (SERS) substrate, using 4-aminobenzenethiol (4-ABT) as probe molecule. The spectral analysis reveals a reproducible enhancement of the 4-ABT Raman signal, allowing detection of this compound from a 10−4 mol L−1 solution. Also, the Raman spectra profile is dependent on the immersion time of the PVG/Cu samples into the 4-ABT solution.