Coupling urea wastewater treatment with hydrogen production using interface-engineered copper oxide–graphitic carbon catalysts

The simultaneous remediation of urea-rich wastewater and production of hydrogen fuel represents a promising route toward sustainable energy and environmental management. Here, we demonstrate an interface-engineered copper oxide–graphitic carbon (CuO/GC) hybrid as a bifunctional electrocatalyst for efficient urea electrolysis. The optimized CuO/GC electrode achieves current densities of 10 mA cm⁻² at 154 mV for the hydrogen evolution reaction (HER) and 1.33 V for the urea oxidation reaction (UOR) versus the reversible hydrogen electrode. In a two-electrode full-urea electrolysis system, CuO/GC delivers 100 mA at 1.65 V and operates stably for over 100 h at an applied cell voltage of 1.7 V. Electrochemical impedance and double-layer capacitance analyses reveal accelerated interfacial charge transfer and an enhanced electrochemical surface area, underscoring the significance of the CuO–GC interface in promoting reaction kinetics. This study highlights the potential of interface-engineered copper-based hybrids for coupling urea wastewater treatment with low-energy hydrogen generation toward integrated environmental–energy technologies.