Accelerating Interfacial Electron Transfer by Constructing NiMn/Ni₃S₂ Heterostructures for Urea Oxidation

The development of highly active and cost-effective electrocatalysts for the urea oxidation reaction (UOR) is critical for facilitating scalable and sustainable hydrogen production. Heterointerface engineering has emerged as an effective strategy to enhance UOR performance by modulating electronic structures and improving charge transfer kinetics. Herein, we designed and fabricate a 3D heterostructure NiMn/Ni₃S₂ supported on foam nickel (NiMn/Ni₃S₂/NF) via in situ growth of nickel-manganese layered double hydroxide (NiMn(OH)_x) on a self-supported sulfurized NF substrate. This unique petal architecture promotes active-site exposure and facilitates interfacial electron transfer between NiMn(OH)_x and Ni₃S₂, which significantly enhances UOR catalytic activity. The as-optimized NiMn/Ni₃S₂/NF catalyst exhibits exceptional performance, achieving a low potential of 1.352 V (vs. reversible hydrogen electrode [RHE]) at 100 mA cm^-2 and a Tafel slope of 13.34 mV dec^-1, outperforming most previously reported UOR catalysts. Moreover, the as-prepared NiMn/Ni₃S₂/NF catalyst demonstrates remarkable stability, retaining high catalytic activity and durability for over 120 h at 10 mA cm^-2. This study provides a rational strategy to design efficient and durable electrocatalysts for energy-related applications.