Facile room temperature synthesis of multifunctional CTAB coated gold nanoparticles

We report a facile single-step method for the room-temperature synthesis of gold nanoparticles (Au-NPs) coated with cationic surfactant, Cetyltrimethylammoniumbromide (CTAB). Au-NPs were synthesized simply by reducing HAuCl4 by ascorbic acid in a high pH reaction medium. The size and yield of the synthesized Au-NPs depended on the CTAB concentration in the solution. It was observed that the lower concentrations of CTAB led to the synthesis of Au-NPs of smaller size. Furthermore, we have seen that the conversion of Au precursor into Au-NPs was more efficient for samples prepared with lower concentrations of CTAB. However, NPs synthesized with CTAB concentrations below the second critical micelle concentration (cmc) showed high size dispersion. The CTAB coated Au-NPs exhibited excellent surface enhanced Raman scattering (SERS) and catalytic properties. In particular, they showed great potential for the catalytic degradation of both azo and non-azo dyes, and trace detection of both fluorescent and non-fluorescent molecules.