Dual-Optimized Medium-Entropy Alloy Heterojunction: Synergistically Enhancing Surface Kinetics and Interfacial Mass Transfer for Hydrazine-Assisted Hydrogen Evolution

To address the prominent “bubble shielding” effect at high current densities during hydrazine oxidation reaction (HzOR) as a replacement for the traditional oxygen evolution reaction (OER), this study successfully designed a medium-entropy heterojunction electrocatalyst (Co_0.226Fe_0.277Ni_0.209Mo_0.288/MoS₂/CC) featuring discontinuous three-phase contact lines through a topological transformation strategy.

The catalyst exhibits unique superwetting properties (superhydrophilic/superaerophobic), significantly enhancing bubble detachment efficiency during gas evolution. In situ microscopic observations reveal that the bubble sizes released from the surface are markedly smaller than those form Pt/C/CC under current densities of 10 and 100 mA cm^–2. In addition, the Co_0.226Fe_0.277Ni_0.209Mo_0.288/MoS₂/CC achieves dual optimization of reaction kinetics and interfacial mass transfer through the synergistic effect of enhanced N₂H₄ adsorption capacity and reduced H* desorption energy barrier, achieves outstanding bifunctional performance in hydrazine-assisted water electrolysis system, requiring overpotential of only 28 mV for HER and work-potential of −6 mV for HzOR to reach a current density of 10 mA cm^–2.