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Diazonium Electrografting vs . Physical Adsorption of Azure A at Carbon Nanotubes for Mediated Glucose Oxidation with FAD‐GDH
Author(s) -
Gross Andrew J.,
Tanaka Shunya,
Colomies Clara,
Giroud Fabien,
Nishina Yuta,
Cosnier Serge,
Tsujimura Seiya,
Holzinger Michael
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202000953
Subject(s) - electrochemistry , adsorption , electron transfer , redox , chemistry , monomer , electrode , carbon nanotube , catalysis , polymer chemistry , covalent bond , inorganic chemistry , polymer , combinatorial chemistry , photochemistry , organic chemistry , materials science , nanotechnology
The electrochemical reduction of aryldiazonium salts is a versatile and direct route to obtain robust covalently modified electrodes. We report here a comparative study of Azure A modified carbon nanotube electrodes prepared by diazonium electrografting and by physical adsorption for bioelectrocatalytic glucose oxidation with fungal FAD‐glucose dehydrogenase from Aspergillus sp . The electrografted and adsorbed electrodes exhibited different reversible electroactivity consistent with polymer‐type and monomer‐type phenothiazine surface assemblies, respectively. The electrografted Azure A electrodes exhibited superior mediated bioelectrocatalysis compared to the adsorbed Azure A electrodes. A more than 10‐fold higher catalytic current up to 2 mA cm −2 at 0.2 V vs . Ag/AgCl together with a similarly low onset potential of −0.05 V vs . Ag/AgCl was observed at the electrografted electrodes. Faster estimated electron transfer kinetics and a +200 mV potential shift for the polymer‐type redox couple vs . the adsorbed monomer‐type couple underlines the favourable driving force for mediated electron transfer with the buried FAD active site for the diazonium‐derived bioelectrode.