Hierarchical structure based on Fe, Mo co-doped Ni ₃ S ₂ and NiFe LDH: Dual-anode boosting efficient hydrogen evolution

Hydrogen energy serves as a secondary energy carrier, and water electrolysis for hydrogen production is a core development direction. By combining the cathode hydrogen evolution reaction (HER) with the dual anode reactions<strong>—</strong>oxygen evolution reaction (OER) and urea oxidation reaction (UOR), it simultaneously achieves mainstream alkaline electrolytic hydrogen production and urea treatment. Here, Ni₃S₂(Fe, Mo)-NiFe LDH, a trifunctional electrocatalyst, is prepared via a two-step hydrothermal method. Density functional theory (DFT) calculations confirmed that co-doping with Mo and Fe optimizes Gibbs free energy of hydrogen adsorption &nbsp;of Ni₃S_2. The doping-modulated Ni₃S₂(Fe, Mo) and NiFe LDH form a hierarchical structure, not only achieving performance complementarity but also further enhancing the overall catalytic activity through interfacial electronic interactions. At 10 mA·cm^–2, the HER overpotential is 91 mV, and the UOR overpotential is 74 mV, which is a reduction of 154 mV compared to OER (228 mV). Moreover, the constructed HER‖OER (HER‖UOR) electrolyzer operates at a voltage as low as 1.55 V (1.41 V), along with 100 h stability.