Fabricated CoFePBA/NF-Derived Mixed Metal Sulfide as Multifunctional Catalysts for Enhanced Urea–Water Electrolysis

This study demonstrates the successful fabrication of mixed-metal CoFePBA/NF with hierarchical 1D + 3D string-bead morphology through in situ conversion, followed by sulfidation to obtain highly active s-CoFePBA/NF. The optimized s-CoFePBA/NF (500 °C) demonstrates exceptional trifunctional electrocatalytic performance, achieving ultralow overpotentials of 226 mV (OER) and 127 mV (HER) at 10 mA cm^-2, along with a remarkable UOR potential of 1.317 V. Remarkably, the assembled s-CoFePBA/NF (500 °C)||s-CoFePBA/NF (500 °C) electrolytic cell requires only 1.60 V for overall water splitting and 1.41 V for urea-assisted water splitting at 10 mA cm^-2, significantly outperforming the commercial IrO₂/NF||Pt/C/NF electrolytic cell (1.53 V). The system maintains excellent stability over 40 h of operation with ∼95% Faradaic efficiency for H₂ production, offering an optimized strategy for urea-wa_ter electrolysis. Therefore, this work represents an advancement in developing multifunctional electrocatalysts for sustainable hydrogen production coupled with urea wastewater treatment.