Electrode Processes in Deep Eutectic Solvent Containing Dissolved Chromium(III) Chloride and Evaluation of Electrocatalytic Activity of Deposited Coatings

The specific features of electrodeposition of coatings from a room-temperature ionic liquid based on a eutectic mixture of choline chloride and ethylene glycol, in which a trivalent chromium salt is dissolved, were considered. The influence of the water content in the electrolyte on the kinetics of electrode processes and the electrodeposition of electrodeposits was shown. It has been established that the introduction of additional water leads to an increase in the current density of the irreversible discharge of Cr(III) ions on a glassy carbon electrode due to a significant decrease in the viscosity of the solution. Coatings deposited from an electrolyte based on a room-temperature ionic liquid demonstrate an increased electrocatalytic activity in the reaction of hydrogen evolution in an alkaline medium. A change in the water content in the chromium plating electrolyte is a factor that allows modulating the electrocatalytic activity of electrodeposits via a controllable change in their chemical composition and surface morphology features.