Electrodeposited Palladium and Nickel Nanoparticles as Electrochemical Sensors for Dicarboxylic Aliphatic Acids

摘要

The electroreduction of oxalic, succinic, tartaric and malic acids in aqueous KCI on glassy carbon electrode (GCE) immobilized with nanoparticles of palladium and nickel was investigated. The surface morphology of the electrodeposited nanoparticles was examined using scanning electron microscopy (SEM). The Pd and Ni-nanostructured films on GCE exhibit an ability to improve dramatically the peak currents of cyclic voltam- mograms of the reduction behavior of all acids under investigation, instead of ill-defined waves obtained on the bare GCE. Obviously, this improvement returns to the electrocatalysis of the electron transfer between the investigated acids and the new modified electrodes. The cyclic voltammetric response of the investigated acids is sensitive to pH as well as of the scan rate. The mechanisms of the electrode reactions and the equivalent circuits for the different acids have been proposed. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) parameters to the charge transfer rate constants associated with the redox processes of the acids are evaluated and discussed.