THE ELECTROCHEMICAL REDUCTION OF NITROPHENOLS ON SILVER GLOBULAR PARTICLES ELECTRODEPOSITED UNDER PULSED POTENTIAL CONDITIONS.

A pulsed electrodeposition technique based on a multipulse sequence of potentials of equal amplitude, duration and polarity was employed for the preparation of highly dispersed silver particles on glassy carbon surfaces (GC/ Ag ). A detailed analysis of the scanning electron microscope images reveals that silver deposit, obtained under pulsed electrodeposition conditions, appears as homogeneously compact and the crystallites are well dispersed on the GC substrate. The globular particles appear isolated or dispersed as twinned and rarely as trimer islands. The resulting silver modified electrode was electrochemically characterized through the reduction of nitrophenol compounds. The potential needed for the reduction of these compounds on the GC/ Ag electrodes is significantly less negative than that observed on the unmodified glassy carbon electrode or bare silver substrates. Under chronoamperometric conditions, the Ag electrodeposited film shows a good catalytic activity and temporal stability regarding the electroreduction of nitrophenol compounds and can be usefully used for the electrochemical massive hydrogenation of these molecules in acidic medium. Moreover, the GC/ Ag electrode was successfully tested as a sensing probe for the analytical detection of nitrophenol compounds under differential pulse voltammetric conditions showing interesting analytical performance in terms of limits of detection and dynamic linear range.