Electrochemical Oxidation of Formic Acid on the Surface of an Anodically Modifi ed Ag15Pd Alloy

Abstract

It was shown that the phase transformation of palladium into its own phase during the selective dissolution of the Ag15Pd alloy proceeds in the instantaneous nucleation mode and is limited by the surface diffusion of Pd ad-atoms to the growing three-dimensional nucleus of the new phase. The kinetic regularities of the electrooxidation of formic acid on an Ag15Pd alloy subjected to preliminary selective dissolution were established using transient electrochemical methods. It was found that the process of anodic destruction of HCOOH in an acidic sulphate solution proceeds at a higher rate on the anodically
modifi ed Ag15Pd alloy, the surface of which is morphologically developed and enriched with palladium as a result of potentiostatic selective dissolution under overcritical polarization conditions. The process of electrooxidation of HCOOH is non-stationary, proceeds in a mixed-kinetic mode and accelerates with increasing anodic potential. Kinetic currents of anodic oxidation of formic acid were determined by the chronoamperometry. A correlation between the value of the electric charge transferred during preliminary anodic modifi cation of the Ag15Pd alloy and the rate of the kinetic stage of the electrooxidation of HCOOH was revealed

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