Electrochemical Behavior of Aromatic Compounds on Nanoporous Gold Electrode

Abstract

This study aimed at investigating the electrochemical behavior of benzene and its substituted derivatives on nanoporous gold and assessing the possibility of utilizing this electrode as a platform for simultaneous detection of different aromatic compounds. Cyclic voltammetric studies were performed with benzene, hydroquinone, catechol, phenol, 2-aminophenol, 2-chlorophenol as well as their mixtures on the nanoporous gold prepared from dealloying of Au x Si 1-x films. The nanoporous structure was found to provide enhanced electro-oxidation of hydroquinone, catechol, phenol, 2-aminophenol and 2-chlorophenol and remarkable fouling resistance in the electro-oxidation of phenol and 2-aminophenol compared to the compact and flat gold electrode. Interestingly, oxidation potentials of these aromatics appear to be affected significantly by the attachment of functional groups to the benzene ring. Based on the onset oxidation potentials, the easiness of oxidation at nanoporous gold was found to follow the order: hydroquinone > catechol > 2-aminophenol > 2-chlorophenol, phenol > benzene. Moreover, nanoporous gold was found to be advantageous over nanoporous platinum for potential application in simultaneous analysis employing voltammetric techniques as it could offer discernable peak potential separation in the electro-oxidation of the different aromatics.

Tunable construction of electrochemical sensors for chlorophenol detection

“…Because of their high conductivity and excellent chemical inertness against environmental corrosion, noble metals like platinum (Pt) 12,49 and gold (Au) 36,38 are widely used as working electrodes in electrochemical CP sensing systems. The high density of electronic states and the number of atomic orbitals within the noble metals enable not only free electron migration in the bulk phase, but also fast heterogeneous electron transfer on the surface, [96][97][98] which is conducive to facilitating the redox reactions of CPs.…”

“…4a, there are mainly two strategies to overcome sluggish kinetics and fouling effect, one is to adjust the electrode surface itself (e.g., electrochemical dealloying), 98 and another is to modify the surface with active materials (e.g., phthalocyanines). 36,96 For the former, Quynh and coworkers 98 have developed a nanoporous electrode through electrochemical dealloying of silicon (Si) out of Au-Si or Pt-Si alloy thin films. With the 3D porous network of interconnected noble-metal ligaments on the order of nanometers (Fig.…”

“…72 Due to the relatively low cost and wide availability of carbon materials, carbon-based electrodes have been widely used ever since graphite electrodes were introduced for electrochemical production of alkali metals. [94][95][96][97][98][99] Diverse carbon-based electrodes emerge, benefiting from the presence of abundant allotropes of carbon including the sp 2 hybridized graphitic carbon materials (graphite, glassy carbon, carbon black, etc. ), and the completely sp 3 hybridized tetrahedral diamond.…”

Electrochemical Molecular Conversion of α-Keto Acid to Amino Acid at a Low Overpotential Using a Nanoporous Gold Catalyst

“…Nanoporous gold (NPG) is promising in electrochemical applications of catalysis and sensing, owing to its advantages, such as high conductivity, catalytic activity, chemical inertness, physical stability, reusability, and facile surface modification. Several efficient electrocatalytic reactions using NPG, including the reduction of CO 2 and H 2 O 2 , oxidation of alcohol, glucose, CO, and aromatic compounds, and hydrogenation reactions of alkynes and alkenes, have been reported [13][14][15][16][17][18][19][20].…”

“…stability, reusability, and facile surface modification. Several efficient electrocatalytic re actions using NPG, including the reduction of CO2 and H2O2, oxidation of alcohol, glu cose, CO, and aromatic compounds, and hydrogenation reactions of alkynes and alkenes have been reported [13][14][15][16][17][18][19][20]. To date, NPG has been mostly prepared by the selective etch ing of a less noble component in gold-containing metal alloys.…”