关键词: CoOOH, 电化学重构, 氧空位, 超亲水表面, 尿素电氧化

Abstract: The conversion of urea-containing wastewater into clean hydrogen energy has gained increasing attention. However, challenges remain, particularly with sluggish catalytic kinetics and limited long-term stability of urea oxidation reaction (UOR). Herein, we report loosely porous CoOOH nano-architecture (CoOOH LPNAs) with hydrophilic surface and abundant oxygen vacancies (O^v) on carbon fiber paper (CFP) by electrochemical reconstruction of the CoP nanoneedles precursor. The resulting three-dimensional electrode exhibits an impressively low potential of 1.38 V at 1000 mA cm⁻² and excellent durability for UOR. Furthermore, in an anion exchange membrane (AEM) electrolyzer, it requires only 1.53 V at 1000 mA cm⁻² for industrial urea-assisted water splitting and operates stably for 100 h without degradation. Experimental and theoretical investigations reveal that rich oxygen vacancies effectively modulate the electronic structure of the CoOOH while creating unique Co₃-triangle sites with Co atoms close together. As a result, the adsorption and desorption processes of reactants and intermediates in UOR are finely tuned, thereby significantly reducing thermodynamic barriers. Additionally, the superhydrophilic self-supported nanoarray structure facilitates rapid gas bubble release, improving the overall efficiency of the reaction and preventing potential catalyst detachment caused by bubble accumulation, thereby improving both catalytic activity and stability at high current densities.

Key words: CoOOH, electrochemical reconstruction, oxygen vacancies, superhydrophilic surface, urea electrooxidation