INFLUENCE OF ANODIC TREATMENT OF NICKEL IN DEEP EUTECTIC SOLVENTS ON ELECTROCATALYTIC ACTIVITY IN OXYGEN EVOLUTION AND UREA OXIDATION REACTIONS.

The influence of anodic potentiostatic treatment of nickel surface in deep eutectic solvents, ethaline and reline (eutectic mixtures of choline chloride with ethylene glycol and urea, respectively), on the electrocatalytic activity in the electrochemical reactions of oxygen evolution and urea oxidation in an aqueous alkaline medium (1 M NaOH) was investigated for the first time. It was shown that, depending on the chosen treatment potential and the nature of the eutectic solvent used, a significant increase in the rate of the studied processes was observed. Specifically, after anodic treatment of nickel under certain conditions, the polarization of the oxygen evolution reaction at a current density of 0.1 A/cm² could be reduced by approximately 150-200 mV, and the maximum current density of urea oxidation could be increased by an order of magnitude (from 0.012 A/cm² to 0.131 A/cm² at a urea concentration of 0.33 mol/dm³ in alkaline solution). The observed increase in electrocatalytic activity after anodic treatment of nickel in deep eutectic solvents is likely related to changes in surface morphology patterns and the nature and concentration of relevant electroactive sites on the electrode surface. The results obtained in this work can be used for the development of highly efficient electrode materials for green hydrogen energy. [ABSTRACT FROM AUTHOR]