Spontaneous modification of carbon surface with neutral red from its diazonium salts for bioelectrochemical systems

Abstract

This study introduces a novel and simple method to covalently graft neutral red (NR) onto carbon surfaces based on spontaneous reduction of in situ generated NR diazonium salts. Immobilization of neutral red on carbon surface was achieved by immersing carbon electrodes in NR-NaNO2-HCl solution. The functionalized electrodes were characterized by cyclic voltammetry (CV), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Results demonstrated that NR attached in this way retains high electrochemical activity and proved that NR was covalently bound to the carbon surface via the pathway of reduction of aryl diazonium salts. The NR-modified electrodes showed a good stabili..