Electrochemical sensing of some dicarboxylic aliphatic acids on glassy carbon electrode modified with electrodeposited platinum nanoparticles

摘要

Electroreduction of oxalic, succinic, tartaric and malic acid in aqueous KC1 on glassy carbon electrode (GCE) immobilized with nanoparticles of platinum was investigated. Platinium nanoparticle (Pt_(NPs)) - modified electrodes were prepared by the electrodeposition with cyclic voltammetric method onto glassy carbon electrode. The surface morphology of the electrode-posited Pt nanoparticles was examined by SEM. Also, the electrochemical properties of the prepared electrodes were investigated with different electrochemical techniques; cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The Pt-nanostructured film on GCE exhibits an ability to improve dramatically the current intensity of the cyclic voltammograms of the reduction behavior of all acids under investigation. Instead of irreversible ill-defined waves obtained on bare GCE, combined with Pt-nanoparticles, the monolayer-modified electrode (Pt/ GCE) gives sensitive reversible responses. Obviously, this improvement returns to the electrocatalysis of the electron transfer between the acids and the new modified electrode. Electrochemical impedance spectroscopy at a fixed potential was performed at treated GCE. The mechanism of the electrode reactions and the equivalent circuits of the GCE for the different acids have been proposed. The different CV and EIS parameters in addition to the charge transfer rate constants associated with the redox processes of the acids are evaluated and discussed.