One-Step Ni-Co Alloy Nanoparticles Electrodeposition from Leach Liquor of Spent Ni-MH Batteries Using a Deep Eutectic Solvent and Its Use Towards Urea Electrooxidation

This work reports a simple, low-cost, and environmentally friendly method to synthesize Ni-Co alloy nanoparticles (Ni-CoNPs) onto a glassy carbon electrode, GCE, and its use towards the efficient urea electrooxidation in basic aqueous media. Ni-CoNPs were directly electrodeposited onto the GCE surface, GCE/Ni-CoNPs by a single potentiostatic step, from the leached liquor of the cathode powder of spent Ni-MH batteries using the reline deep eutectic solvent, DES, as leaching agent, and electrolytic bath. The GCE/Ni-CoNPs were immersed in a 1 M KOH, 0.33 M urea aqueous solution and used as anode for urea electrochemical oxidation. The mass activity of this electrode depicted a maximum value of 27,900 mAmg⁻¹ cm⁻² at ca 0.5 V vs. Ag/AgCl and a steady state mass activity of 1690 mAmg⁻¹ cm⁻² during the potentiodynamic and potentiostatic evaluation. The performance of the GCE/Ni-CoNPs electrode reported in this work is similar or better than other electrodes reported for this purpose using more sophisticated, time-consuming, and costly methods.

Graphical Abstract