Optical enhancing properties of anisotropic gold nanoplates prepared with different fractions of a natural humic substance

The results of this work demonstrate the properties of suspensions of humic substances (HS) used as reducing and templating agent for the formation of gold nanostructures. It is further established that a considerable degree of control over the size and shape of the nanoparticles can be achieved by selecting the appropriate humic fraction and adjusting the pH of the working suspension. These gold nanostructures can sustain surface plasmon resonances and exhibit optical enhancing properties that make them suitable for plasmonic applications and optical enhancement such as surface-enhanced Raman scattering (SERS). The efficiency of the nanostructures as a SERS substrate is illustrated enhancing the Raman spectrum of 2-mercaptobenzothiazole (MBT), a common organic pollutant.