Leaf-Vein-Inspired Mo-Modulated NiCoP@CNT/CW Electrodes for Efficient Urea-Assisted Hydrogen Production.

In this work, a leaf-vein-inspired self-supporting electrode was fabricated by in situ growth of Mo-modulated NiCoP on a carbonized wood/carbon nanotube scaffold (MoOx-NiCoP@CNT/CW) for urea-assisted hydrogen production. Carbonized wood serves as the "primary veins", providing a 3D conductive framework and mechanical support. Carbon nanotube network acts as the "secondary veins", accelerating charge transport and mass diffusion. MoOx optimizes the electronic structure of NiCoP and synergizes with the hierarchical structure to enhance the accessibility of active sites and reaction kinetics. The electrode exhibits excellent performances in hydrogen evolution reaction (HER) and urea oxidation reaction (UOR), with potentials of 252 mV and 1.33 V at 100 mA cm-2, respectively. In situ electrochemical impedance spectroscopy reveals the indirect oxidation mechanism of UOR and its superior reaction kinetics compared to OER, as well as the Volmer-Heyrovsky mechanism of HER. In the HER||UOR coupled system, the cell voltage at 100 mA·cm-2 was only 1.36 V, which is 244 mV lower than that of conventional water electrolysis, while demonstrating high Faradaic efficiency (98.7%) and long-term stability (over 310 h). This work presents a biomimetic strategy that combines electronic-structure regulation with hierarchical transport frameworks, opening a new avenue for low-energy-consumption hydrogen production and the resource-efficient utilization of urea.