Electrografting of N鈥?N鈥?dimethylphenothiazin-5-ium-3,7-diamine (Azure A) diazonium salt forming electrocatalytic organic films on gold or graphene oxide gold hybrid electrodes
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- 作者：C. G贸mez-Anquela ; M. Revenga-Parra ; J.M. Abad ; A. Garc铆a Mar铆n ; J.L. Pau ; F. Pariente ; J. Piqueras ; E. Lorenzo
- 关键词：Aryldiazonium salts ; Electrografting ; Redox mediator ; Conductive polymer ; NADH oxidation ; Hybrid electrodes.
- 刊名：Electrochimica Acta
- 出版年：10 January, 2014
- 年：2014
- 卷：116
- 期：Complete
- 页码：59-68
- 全文大小：1463 K
文摘
Electroactive films containing redox active phenothiazine moieties are covalently bound onto gold and graphene oxide gold hybrid electrodes, using reductive redox grafting of N鈥?N鈥?dimethylphenothiazin-5-ium-3,7-diamine (Azure A) diazonium salt. The grafting procedure is based on continuous voltammetric potential sweep of solutions containing the phenothiazine diazonium salt previously generated in situ. Control of the film thickness, electroactivity and stability can easily be exerted through appropriate choice of the concentration and number of potential scans performed. Cyclic Voltammetry, Electrochemical Quartz Crystal Microbalance (EQCM) and Spectroscopic Ellipsometry are used to characterize the growth process as well as the viscoelastic properties of the resulting stable electrografted films. The electron transfer reactions through the films are mediated by the presence of the Azure A redox moieties, which show a quasi-reversible electrochemical response and exhibit a potent electrocatalytic effect toward the oxidation of NADH. This electrocatalytic model has been used to compare the properties of Azure A electrografted films generated on gold electrodes with those obtained on hybrid electrodes composed by graphene oxide modified gold electrodes.