Local Charge Modulation Induced the Formation of High-Valent Nickel Sites for Enhanced Urea Electrolysis

Ni-based electrocatalysts are considered to be significantly promising candidates for electrocatalytic urea oxidation reaction (UOR). However, their UOR activity and stability are severely enslaved by the inevitable Ni group self-oxidation phenomenon. In this study, the glassy state NiFe LDH with uniform Cu dopant (Cu-NiFe LDH) by a simple sol–gel strategy is successfully synthesized. When served as the UOR catalyst, Cu-NiFe LDH required a 123 mV lower potential for UOR at both 10 and 100 mA cm⁻² in comparison with the conventional anodic OER. It can also operate steadily for more than 300 h at 10 mA cm⁻². The in-depth investigation reveals that Cu incorporation can optimize the local electronic structure of Ni species to induce high-valent Ni sites. The high-valent Ni sites would act as the active center during the proposed energetically favorable UOR route, which directly reacts on the high-valent Ni sites without self-oxidation inducing the formation of NiOOH species, resulting in a boosted electrocatalytic UOR activity and stability. © 2024 Wiley-VCH GmbH.