Electrooxidation of urea in alkaline solution using nickel hydroxide activated carbon paper electrodeposited from dmso solution

Electrooxidation of urea plays a substantial role in the elimination of urea-containing wastewater and industrial urea. Here, we report the electrodeposition of nickel hydroxide catalyst on commercial carbon paper (CP) electrodes from dimethyl sulphoxide solvent (Ni(OH)₂-DMSO/CP) for urea electrooxidation under alkaline conditions. The physicochemical features of Ni(OH)₂-DMSO/CP catalysts using scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the Ni(OH)₂-DMSO/CP catalyst shows nanoparticle features, with loading of <1 wt%. The cyclic voltammetry and electrochemical impedance spectroscopy revealed that the Ni(OH)₂-DMSO/CP electrode has a urea oxidation onset potential of 0.33 V vs. Ag/AgCl and superior electrocatalytic performance, which is a more than 2-fold higher activity in comparison with the counterpart Ni(OH)₂ catalyst prepared from the aqueous electrolyte. As expected, the enhancement in electrocatalytic activity towards urea was associated with the superficial enrichment in the electrochemically active surface area of the Ni(OH)₂-DMSO/CP electrodes. The results might be a promising way to activate commercial carbon paper with efficient transition metal electrocatalysts, for urea electrooxidation uses in sustainable energy systems, and for relieving water contamination.