Surface reconstruction of Cu-Doped Ni(OH)2 during Electrolysis for enhanced urea oxidation

Copper (Cu) doping was introduced to enhance the valence state of nickel atoms in nickel hydroxide (Ni(OH) 2 ), significantly facilitating the formation of NiOOH. The synthesized catalysts demonstrated outstanding urea oxidation reactivity (UOR), achieving an operating potential as low as 1.283 V (vs. RHE) at a current density of 50 mA cm −2 . This value is significantly lower than the oxygen evolution reaction (OER) potential of 1.561 V, and the catalysts exhibited excellent long-term stability, maintaining activity for over 150 h. This study offers theoretical insights into the design of non-precious metal catalysts for urea oxidation reactions , with a particular focus on effectively promoting surface reconstruction. • Cu doping was employed to enhance the valence state of Ni atoms in Ni(OH) 2 . • The catalytic activity of (Cu-Ni(OH) 2 ) is significantly enhanced. • The catalyst demonstrates long-term stability. • Promote the application of electrocatalytic urea oxidation reaction (UOR). In addressing the challenge posed by the substantial overpotential required by oxygen evolution reaction (OER), considerable attention has been directed toward urea oxidation reaction (UOR) as a promising alternative. This oxidation process reduces the energy input commonly linked to the excessive overpotential in OER and concurrently enables the elimination of urea from wastewater streams. These combined attributes indicate considerable promise for practical implementation in industrial contexts. Nickel (Ni)-based hydroxides have been widely recognized for their significant role in UOR. In this study, Cu doping was employed to enhance the valence state of Ni atoms in Ni(OH) 2 , thereby facilitating the formation of Ni oxyhydroxide (NiOOH). The Cu-Ni(OH) 2 catalyst exhibited significantly enhanced catalytic activity in UOR compared to pure Ni(OH) 2 . The synthesized catalysts exhibited exceptional performance in the urea oxidation reaction, achieving a low operational voltage of 1.283 V at a current density of 50 mA cm −2 , while also demonstrating impressive stability over extended periods, exceeding 150 h. The findings of this investigation offer valuable theoretical perspectives for the development of non-precious metal-based catalysts, which can efficiently promote surface reorganization during the reaction.