Fe2N-modulated Mo2N/MoO2 multiple heterostructures for optimized electron configuration and reaction dynamics in alkaline hydrogen evolution reaction

Abstract

Mo-based catalysts have received widespread attention for their promising hydrogen evolution reaction (HER) efficiency. However, single Mo-based catalysts still have some shortcomings in terms of catalytic activity. Designing heterostructure is an effective strategy to optimize electron configuration, accelerate HER dynamics and modulate microstructure. Herein, a novel cross-linked sheet-like r-FeMo/NF (Fe₂N/Mo₂N/MoO₂) electrocatalyst with multiple heterostructures was prepared by a facile two-step method involving hydrothermal growth followed by nitridation, which directly formed the active material on nickel foam (NF). The formation of multiple heterostructures results in the redistribution of electrons between Fe and Mo species, promoting charge transfer and improving HER activity. As a result, the as-prepared r-FeMo/NF catalyst demands a low overpotential of 46.1 mV to drive the current density of 10 mA cm⁻² for the HER in 1 M KOH. Moreover, it demonstrates outstanding long-term stability, maintaining excellent performance for 100 h at both 10 and 100 mA cm⁻². This work can provide valuable insights into designing highly efficient electrocatalysts with multiple heterostructures.