Platinum Layer Formation on a Self-assembled Monolayer by Electrochemical Deposition

A platinum metal-self-assembled monolayer (SAM)–gold substrate sandwich structure without a short circuit between the two metals was successfully constructed by electrochemical deposition of platinum on top of a 1,4-benzenedimethanethiol (BDMT) SAM-covered Au(111) substrate. Deposition of Pt was carried out by electrochemical reduction of Pt ions, which were adsorbed on free thiol end groups of the BDMT SAM, in a Pt ion-free sulfuric acid solution. Electrochemical measurements and X-ray photoelectron spectroscopy (XPS) showed the reduction of the adsorbed Pt ions to metallic platinum on top of the SAM. After a cathodic potential scan of the Pt–SAM–Au electrode to −1.25 V in 0.1 M KOH solution, a typical cyclic voltammogram of the Au(111) electrode was obtained, showing that the BDMT SAM was reductively desorbed with a Pt layer and that no platinum was deposited directly on the Au(111) surface.