Synergistic Urea Oxidation and Hydrogen Evolution over MoC/Co/NCNT-Based Electrocatalysts for Cost-Effective Alkaline Electrolysis

To facilitate scalable hydrogen production via water splitting, it is highly desirable to develop efficient electrocatalysts to ameliorate the sluggish kinetics of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report the rational design of a multicomponent electrocatalyst comprising molybdenum carbide nanoflakes and metallic cobalt encapsulated within nitrogen-rich carbon nanotubes (MoC/Co/NCNT) supported on nickel foam. The obtained MoC/Co/NCNT shows an exceptionally low overpotential of 33 mV at 10 mA cm–2 for alkaline HER, attributed to the synergistic interactions among MoC, Co, and NCNT. Density functional theory (DFT) calculations indicate this structure can reduce alkaline HER energy barriers. Further integration with NiFe-layered double hydroxide (LDH) imparts pronounced bifunctionality, enabling not only efficient OER but also thermodynamically favorable urea oxidation reaction (UOR), as confirmed by DFT results. Configured as a urea-assisted electrolyzer with MoC/Co/NCNT as the cathode and MoC/Co/NCNT@LDH as the anode, the system achieves 100 mA cm–2 at a cell voltage of just 1.46 V, which is 220 mV lower than that of traditional water electrolysis and surpasses many previously reported urea electrolyzers. This work provides a promising strategy for energy-efficient and cost-effective hydrogen production in alkaline media through integrated HER and UOR electrocatalysis.