Influence of N-octanoyl-N-methylglucamine and N-decanoyl-N-methylglucamine on the kinetics and mechanism of Zn2+ ions electroreduction

• The inhibiting influence of two neutral surfactants OMG and DMG on Zn2+ electroreduction was shown.
• Larger inhibiting effect is observed in the presence of N-decanoyl-N-methylglucamine (DMG).
• The first step is slower thus determining the rate of the whole process.
• Different mechanistic schemes assuming a two-step character of Zn2+ electroreduction were discussed.
• At a certain surfactant concentration the change of electroreduction mechanism is observed.

We examined the electroreduction of Zn2+ in NaClO4 as a supporting electrolyte in the presence of neutral surfactants of various molecular sizes on a mercury electrode. The studies were carried out at different temperatures. The inhibiting effect of N-decanoyl-N-methylglucamine (DMG) on the kinetics of the investigated electrode process was stronger compared to that of N-octanoyl-N-methylglucamine (OMG). In order to describe the Zn2+ reduction in the studied systems, four mechanisms were taken into consideration: EE, CE, IA, and IE. Ion transfer was considered as the most probable first step, whereas electron transfer or reagent adsorption were postulated to be the second step of the electrode process.

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