The electrochemical deposition of cobalt binary alloys with transition metals has received recently much attention due to some characteristic properties and possible practical applications of the coatings. These alloys, besides high electrocatalytical properties, exhibit useful properties such as high corrosion resistance and premium hardness. Additionally, these alloys are also seen as environmentally safe substitutes for hard chromium plating and a new materials for microelectronic and microelectromechanical systems and ultralarge-scale integrated systems.

The present work aims to deposit of active cobalt alloys as catalytic coatings for hydrogen evolution. Electrodeposition mechanism and kinetics of cobalt-based alloys deposition was studied by the electrochemical methods. Chronoamperometry and cyclic voltammetry techniques were combined with electrochemical quartz crystal microbalance to analyze this process in details. The proper adjustment of the process of electrolysis has a crucial role on the composition, and therefore structure and morphology of the deposited coatings, which decide about their electrocatalytic properties. In the present investigations, the composition of the citrate electrolyte with different additives, potential and current density were changed systematically in ranges within which they significantly effect on the composition and structure of the resulting cobalt alloys. The morphology, structure and the composition of the deposited alloys was identified by SEM, XRD, XRF and EDS techniques. Also we try to clarify the effect of the additives in enhancing the high activity for hydrogen evolution. The electroactivity of the coatings were analyzed by different electrochemical techniques.

This work was supported by the Polish National Center of Science under grants 2016/21/B/ST8/00431 and the research was carried out in the frames of COST Action MP1407 (e-MINDS).