Surface-Enhanced Raman Spectroscopic Studies of Dissociative Adsorption of Amino Acids on Platinum and Gold Electrodes in Alkaline Solutions

Abstract

The dissociative adsorption of amino acids on Pt and Au electrodes in 0.1 M NaOH solutions was studied by cyclic voltammetry and surface-enhanced Raman spectroscopy (SERS). The intermediate species has been determined as adsorbed cyanide, which is designated by a potential-dependent vibration band around 2110 cm -1 on both Pt and Au surfaces. The dissociation of glycine can be observed on Pt surface in a wide potential region to form cyanide, while the dissociation of serine and threonine occurs at relatively high potentials along with the oxidation of their functional groups. The onset potential of dissociation of amino acids on the Pt surface increases in the order glycine < threonine < serine. It has been revealed that the self-inhibition of amino acid oxidation is originated from the strongly adsorbed cyanide, which is oxidized at potentials above 0.2 V vs SCE. On gold surfaces, cyanide species can be formed only from anodic oxidation of amino acids. The present study reveals characteristic interactions between amino acid molecules and metallic electrode surfaces, as well as the role of amine group in the adsorption configuration.

Electrochemical Oxidation of Glycine with Bimetallic Nickel−Manganese Oxide Catalysts

“…Sun et al. reported that on Au surfaces, electrooxidation of glycine forms cyanide . Using in‐situ Raman spectroscopy, glycine adsorption on polycrystalline Pt and Au electrode was studied by the same group and they demonstrated that dissociative adsorption of glycine and the dissolution of metals occurs due to the formation of OCN − .…”

“…[15] Sun et al reported that on Au surfaces, electrooxidation of glycine forms cyanide. [16] Using in-situ Raman spectroscopy, glycine adsorption on polycrystalline Pt and Au electrode was studied by the same group and they demonstrated that dissociative adsorption of glycine and the dissolution of metals occurs due to the formation of OCN À . Furthermore, Ag nanoparticle containing electrodes were employed in kinetics measurement of glycine electrooxidation and demonstrate high heterogeneous rate constant of k s = 5.4 × 10 8 cm 3 mol À 1 s À 1 and diffusion coefficient of 7.7 × 10 À 6 cm 2 s À 1 using Laviron's equation.…”

Electrodeposition of Insulating Thin Film Polymers from Aliphatic Monomers as Transducers for Biosensor Applications

“…From the literature, glycine has attracted extensive attention in recent years with investigations on single crystal electrodes (Huerta et al, 1997;Zhen et al, 2004) as well as on polycrystalline electrodes (MacDonald et al, 1997) due to its small size and chemical and biological importance. Many voltammetry studies on single crystal electrode coupled to several in situ techniques such as infrared (FTIRS) or Raman (Xiao et al, 2002) SERS spectroscopy and quartz crystal microbalance were performed. Different electrode materials were used.…”

Preparation of Au/TiO2 nanocomposites and their catalytic activity for DPPH radical scavenging reaction

“…In this process, adsorption of Cl • or Cl − likely occurs on the Au surface since Cl − has a high affinity with gold [35,36]. While in the DMAB reduction, it is possible that (CH 3 ) 2 NH adsorbs on the surface of nanoparticles, since amines in general have a high affinity with gold [37,38]. Adsorption of these species can alter the electronic state of Au surfaces, whereby changing their catalytic activity.…”