A SERS spectroelectrochemical investigation of the interaction of 2-mercaptobenzothiazole with copper, silver and gold surfaces

The interaction of the sulfide mineral flotation collector, 2-mercaptobenzo thiazole, with silver, copper and gold surfaces has been investigated by su rface enhanced Raman scattering (SERS) spectroscopy. 2-mercaptobenzothiazol e, the copper, silver and gold compounds of this species, and the dithiolat e, 2,2'-dithiobis(benzothiazole) were characterised by C-13 NMR and Raman s pectroscopy to provide a basis for identifying surface species. SERS invest igations showed that, at pH 4.6 where the solution species is in the proton ated form, and at 9.2, where it is present as the ion, adsorption on each m etal occurs over a wide potential range. Attachment of the organic compound occurs through bonding between the exocyclic sulfur atom and metal atoms i n the surface. X-ray photoelectron spectroscopy confirmed that the adsorbed layer was of monolayer thickness. Adsorption of the protonated 2-mercaptob enzothiazole occurs on copper at pH 4.6 at potentials below that at which c harge transfer adsorption commences.