Electrochemical introduction of amino group to a glassy carbon surface by the electrolysis of carbamic acid

The electrocatalytic activity of a glassy carbon electrode with regard to the oxidation of ammonium carbamate increased with the electrolysis time because of the electrochemical modification of the electrode surface. From X-ray photoelectron spectroscopy data, it was found that a carbon-nitrogen bond was newly formed due to the electrode oxidation of carbamic acid at +1.0 V vs Ag/AgCl. Redox waves of catechol bound to amino group were observed at +0.05 V vs Ag/AgCl when cyclic voltammetry of catechol was carried out by using a glassy carbon electrode pre-electrolyzed in ammonium carbamate solution. This indicates that catechol can be attached to the electrolyzed surface by the reaction of the amino group bound to the pre-electrolyzed electrode surface and 1,2-benzoquinone formed by electrode oxidation. This result supports the concept that an amino group can be introduced by electrolysis in which ammonium carbamate is used as the electrolyte. The electrochemical introduction of the amino group may have occurred due to the decomposition of carbamaic acid attached to the carbon electrode surface. (c) 2006 The Electrochemical Society. [DOI: 10.1149/1.2402127] All rights reserved.