J. Technology and Education, Vol.21, No.1, pp.1-7 (2014)

研究論文

 

金電極の表面修飾がアスコルビン酸の電気化学的酸化に及ぼす影響

 

加藤正敏，本間俊将，近藤みずき，桑原敬司^*，下村雅人

長岡技術科学大学　生物系　(〒940-2188 新潟県長岡市上富岡町1603-1)

* kuwataka@vos.nagaokaut.ac.jp

 

Influence of Surface Modification of Gold Electrodes on Electrochemical Oxidation of Ascorbic Acid

 

Masatoshi KATO, Toshimasa HOMMA, Mizuki KONDO, Takashi KUWAHARA

and Masato SHIMOMURA

Department of Bioengineering, Faculty of Engineering, Nagaoka University of Technology

(1603-1, Kamitomioka-machi, Nagaoka 940-2188, Japan)

 

(Received November 29,2013; Accepted December 26, 2013)

 

Abstract

For ascorbic acid fuel cells, an electrochemical oxidation of ascorbic acid has studied by using gold electrodes modified with self-assembled thiol monolayers. The thiol monolayers were formed by immersing the gold electrode into aqueous or ethanolic solutions containing 10 mM of thiol. The surface modification of the electrode with positively charged thiol monolayers shifted the onset potential for electrochemical oxidation of ascorbic acid to negative values. In contrast, modification of the hydrophobic thiol monolayer shifted the onset potential to positive values. The reaction kinetics for the electrochemical oxidation of ascorbic acid were analyzed with the rotating disk electrode technique. The kinetic currents obtained using electrodes modified with hydrophilic thiol monolayers were higher than those obtained using bare gold electrodes. The modification of the surface of the electrode with negatively charged monolayers and the hydrophobic monolayer decreased the kinetic current. Therefore, the positively charged electrode materials are effectively employed as an anode of the ascorbic acid fuel cell.

Key words: Ascorbic acid, self-assembled monolayer, fuel cell, reaction kinetics