Electrochemical Response by Adsorption of Reactive Species on the Electrode Surface

ハンノウ　カガクシュ　ノ　デンキョク　ヒョウメン　ヘノ　キュウチャク　ニヨル　デンキ　カガクテキ　オウトウ

Onoda, Mitsuyoshi

分子機能電極

粉砕グラファイト電極

ドーパミン

電極触媒効果

吸着

Bioelectrochemistry

molecular functional electrode

pulverized graphite electrode

dopamine

electrocatalytic effect

adsorption

In "bioelectrochemistry", which elucidates the advanced mechanism of living organisms that utilize the flow of electrons and ions, it is possible to realize the electrochemical reaction of biological-related substances such as enzymes under mild conditions, so expansion to biosensors and bio-fuel cells, etc. is being considered, and the best method for analyzing electrode catalytic function is probably cyclic voltammet1-y. In phosphate buffer solution, pretreatment of graphite crushed using a ball mill (pulverized graphite, pGr) as an electrode resulted in enhancement of the redox peaks of dopamine (DA) on its cyclic voltammogram. The peak current of DA was appreciably affected by the experimental conditions at pretreatment such as pulverized time. The effect of enhancing the current response (electrode catalytic effect) is that the roughening of the glassy carbon electrode (GCE) surface is emphasized due to the coating of pGr by the pulverization treatment of graphite. That is, it is considered that carbonyl group (C=O), carboxy group (-COOH), epoxide, etc. introduced into the pGr surface due to pulverization or electrolysis treatment, moreover, stacking of benzene ring surface, π-π interactionbetween pGr and DA, hydrogen bond, etc. are involved as catalysts for redox reaction of DA. In addition, as these mentioned above are an electrochemical phenomenon in PBS (H_3P0_4), it is expected that chemical species such as phosphate groups (H_2PO_4^-, HPO_4^{2-}，PO_4^{3-}) will be introduced on the pGr surface. On the other hand, in the sweep rate dependence of such current response characteristics, if there is a linear relationship between the peak current values (oxidation peak, Ipa and reduction peak, Ipc) and the sweep rate, from the Nemst equation which is the basic equation in electrochemistry, the electrode active species (DA) is suggested to be adsorbed on the electrode surface, and is considered to be an index of the surface adsorption control mechanism.