The effect of corrosion treatment on the electrochemical activity of Ni-based electrode materials

Recently, in a fairly significant amount of work, attention has been paid to the study of catalytic properties and synthesis of chalcogenide materials, in particular, sulfides of metals of the iron group. Nickel sulfides of the NiS and Ni3S2 types are of particular interest. These materials have a fairly high electrical conductivity comparable to the conductivity of pure nickel, as well as high catalytic activity in the process of electroreduction of oxygen. The purpose of this work is to study the effect of segregation of sulfuric acid in the form of sulfides and adsorbed sulfur during corrosion treatment on the electrochemical properties of galvanic nickel deposits. Based on the results of cyclic vol-amperometry, it is shown that an increase in the duration of the corrosion treatment of bright sulfur-containing nickel deposits in acetic acid, accompanied by an increase in the surface sulfur content, leads to an increase in the current densities of the cyclic volt-ampere curves. The increase in the current densities of the cyclic volt-ampere curves obtained on sulfur-free nickel deposits is facilitated by an increase in the duration of exposure in a saturated solution of sodium sulfide. Thus, regardless of the type of treatment, the segregation of nickel sulfides or adsorbed sulfur leads to an increase in the electrochemical activity of nickel-based electrodes.