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Surface modification is a hot topic in electrochemistry and material sciences because it affects the way materials are used. In this paper, a method for covalently attaching carboxyphenyl (PhCOOH) groups to a gold electrode is presented. These groups were grafted onto the electrode surface electrochemically via reduction of aryldiazonium salt. The resulting grafted surface was characterized using cyclic voltammetry (CV) before and after the functionalization procedure to validate the presence of the grafted layer. The grafting of PhCOOH groups was confirmed by analyzing electrode thickness and composition by ellipsometry and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations indicated that the grafted layers provide a stable platform and resolved, for the first time, their interactions with oxygen.

Grafting of electrodes with diazonium salts using cyclic voltammetry (CV) is a well-established procedure for surface modification. However, little is known about the effect of the concentration of the diazonium salt on the number of layers grafted on the electrode surface. In this work, the impact of concentration on the grafting of 4-carboxybenzenediazonium (4-CBD) onto a glassy carbon electrode (GCE) is elucidated. The number of layers grafted on the GCE was linearly dependent on the concentration of 4-CBD and varied between 0.9 and 4.3 when the concentration was varied between 0.050 and 0.30 mmol/L at 0.10 V.s−1. Characterization of modified glassy carbon surface with X-ray photoelectron spectroscopy (XPS) confirmed the grafting of carboxyphenyl layer on the surface. Grafting with 0.15 mmol/L 4-CBD (1 CV cycle) did not form a detectable amount of carboxyphenyl (CP) moieties at the surface, while a single scan with higher concentration (2.5 mmol/L) or multiple scans (22 cycles) gave detectable signals, indicating formation of multilayers. We also demonstrate the possibility of removing the thin layer grafted on a glassy carbon electrode by applying high oxidation potential +1.40 V.

Finding novel strategies for surface modification is of great interest in electrochemistry and material sciences. In this study, we present a strategy for modification of a gold electrode through covalent attachment of triazole (TA) groups. Triazole groups were electrochemically grafted at the surface of the electrode by a reduction of in situ generated triazolediazonium cations. The resulting grafted surface was characterized before and after the functionalization process by different electrochemical methods (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)) confirming the presence of the grafted layer. The grafting of TA on the electrode surface was confirmed using analysis of surface morphology (by atomic force microscopy), the thickness of the grafted layer (by ellipsometry) and its composition (by X-ray photoelectron spectroscopy). Density functional theory (DFT) calculations imply that the grafted triazole offers a stronger platform than the grafted aryl layers.

Surface modification of materials is accomplished using a vast number of molecules that possess a special affinity (SAMS) or are prone to undergo chemical reactions with the surface groups of the substrate-usually hydroxylated oxide layers (phosphonic or carboxylic acids, silanes, etc.). Probably the most direct mode to achieve this task is the use of the diazonium salts. This surface modification permits an easy way for tuning the properties of materials and adding some new interesting functionality that can be explored for: sensor construction, corrosion protection, catalysis, etc. In this work, we explored the use of diazonium heterocyclic compound to graft the surface of the glassy carbon electrode through di electrochemical reaction of the transformed amino heterocyclic moiety into the corresponding diazonium salt. The grafted surface is analyzed by a number of electrochemical and surface analysis techniques.

Surface modification of materials is accomplished using a vast number of molecules that possess a special affinity (SAMS) or are prone to undergo chemical reactions with the surface groups of the substrate-usually hydroxylated oxide layers (phosphonic or carboxylic acids, silanes, etc.). Probably the most direct mode to achieve this task is the use of the diazonium salts. This surface modification permits an easy way for tuning the properties of materials and adding some new interesting functionality that can be explored for: sensor construction, corrosion protection, catalysis, etc. In this work we explored the use of diazonium heterocyclic compound to graft the surface of the glassy carbon electrode through direct grafting (by the isolation of the diazonium salt) and "in situ" electrochemical reaction of the transformed amino heterocylic moiety into the corresponding diazonium salt. The grafted surface is analyzed by a number of electrochemical and surface analysis techniques.