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 the 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 exhibited an impressively low potential of 1.38 V at 1000 mA·cm⁻² and excellent durability for UOR. Furthermore, when tested in an anion exchange membrane (AEM) electrolyzer, it required only 1.53 V at 1000 mA·cm⁻² for industrial urea-assisted water splitting and operated stably for 100 h without degradation. Experimental and theoretical investigations revealed 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 could be finely tuned, thereby significantly reducing thermodynamic barriers. Additionally, the superhydrophilic self-supported nanoarray structure facilitated 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.

Heteroatom doping has emerged as an effective strategy to enhance the performance of electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Traditional doping methods often involve harsh chemical treatments and tedious procedures, hindering their widespread applications. Furthermore, although dynamic surface reconstruction in alkaline media is commonly observed in bimetallic compounds, strategies to regulate this reconstruction behavior for enhanced HER and OER performances remain inadequately explored. Herein, we report an ultrafast (≤ 300 s) and mild electrochemical doping approach to fabricate Se-doped NiCo₂S₄ hollow nanoarrays on carbon fiber papers (a-NiCo₂(S_1−xSe_x)₄), investigating the role of Se in enhancing overall water splitting performance. Under HER conditions, a-NiCo₂(S_1−xSe_x)₄ demonstrates remarkable stability, with Se tuning the electronic structure to optimize intermediate adsorption and facilitate H₂O dissociation. While under OER conditions, Se doping lowers the energy barrier for reconstruction and promotes transformation into active Se, S co-doped Ni_0.33Co_0.67OOH nanosheets. The optimal samples exhibit superior HER and OER activity, requiring a cell voltage of 1.578 V to deliver a current density of 100 mA·cm⁻² for overall water splitting. This work not only introduces a facile method for Se doping but also provides comprehensive insights into the structure–composition–activity relationship for Se-doped bimetallic sulfide.