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Abstract
The electrochemical reduction of di-carboxylic acids; oxalic, succinic, malic, tartaric, maleic and fumaric have been studied on both bare and modified GCE with Ni, Pd, Pt and Au nanoparticle electrodes in aqueous media solution of 0.1 M KCl. The modification has been carried out using Ni, Pd, Pt and Au metals. The nanoparticles of the chosen metal ions were prepared on the GC electrode surface by the electrodeposition technique. The surface morphology of the electrodeposited nanoparticles were examined by Scanning Electron Microscopy (SEM). The electrochemical properties of the prepared electrodes were investigated with different electrochemical techniques; cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS), using ferricyanide as a probe. Cyclic Voltammetric, Chronoamperometric and Electrochemical Impedance Spectroscopic techniques used for the investigation of the electrochemical behavior of the particulate acids. The modification of the electrode with metal nanoparticles enables the appearance of cyclic voltammogram peaks much better than those obtained on the bare electrode. All acids undergo totally irreversible redox reaction on GCE modified with Ni, Pd and Au nanoparticle electrodes, whereas a reversible behavior on the GCE modified with PtNPs is obtained. It is observed that, the behavior of the investigated acids is sensitive to pH, as well as of the scan rate. The peak potential locations of the acids depend on the structure of each acid. Further, the lowest unoccupied molecular orbital (LUMO) energies of the acids under investigation have been theoretically calculated and are compared with their electroreduction potentials. Key words: Electrodeposition; metals nanoparticle; electroreduction; di-carboxylic.