Mo Migration‐Induced Crystalline to Amorphous Conversion and Formation of RuMo/NiMoO4 Heterogeneous Nanoarray for Hydrazine‐Assisted Water Splitting at Large Current Density

Manipulating the atomic structure of the catalyst and tailoring the dissociative water‐hydrogen bonding network at the catalyst‐electrolyte interface is essential for propelling alkaline hydrogen evolution reactions (HER) and hydrazine oxidation reaction (HzOR), but remains a great challenge. Herein, we constructed an advanced a‐RuMo/NiMoO4/NF heterogeneous electrocatalysts with amorphous RuMo alloy nanoclusters anchored to amorphous NiMoO4 skeletons on Ni foam by a heteroatom implantation strategy. Theoretical calculations and in‐situ Raman tests show that the amorphous and alloying structure of a‐RuMo/NiMoO4/NF not only induces the directional evolution of interfacial H2O, but also lowers the d‐band center (from ‐0.43 to ‐2.22 eV) of a‐RuMo/NiMoO4/NF, the Gibbs free energy of hydrogen adsorption (ΔGH*, from ‐1.29 to ‐0.06 eV), and the energy barrier of HzOR (ΔGN2(g) = 1.50 eV to ΔGN2* = 0.47 eV). Profiting from these favorable factors, the a‐RuMo/NiMoO4/NF exhibits excellent electrocatalytic performances, especially at large current densities, with an overpotential of 13 and 129 mV to reach 10 and 1000 mA cm‐2 for HER. While for HzOR, it needs only ‐91 and 276 mV to deliver 10 and 500 mA cm‐2, respectively. Further, the constructed a‐RuMo/NiMoO4/NF||a‐RuMo/NiMoO4/NF electrolyzer demands only 7 and 420 mV to afford 10 and 500 mA cm‐2.