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

Abstract

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.