Enhancing hydrogen electrocatalytic oxidation on Ni₃N/MoO₂ in-plane heterostructures in alkaline solution

Nickel (Ni)-based materials act as one of the most promising candidates as platinum-group-metal-free (PGM-free) electrocatalysts for hydrogen oxidation reaction (HOR) in alkaline solution. Nevertheless, the electrocatalytic activity of pure Ni is significantly limited due to the sluggish kinetics under alkaline condition. To accelerate the kinetics, constructing heterostructures and nitride structures have been developed as two representative strategies. Here, we combined the two methods and presented a facile synthesis of the sheet-like Ni₃N/MoO₂ in-plane heterostructures for enhanced HOR in alkaline electrolytes. Relative to Ni or Ni₃N, the Ni₃N/MoO₂ in-plane heterostructures exhibited a significantly increased mass activity by 8.6-fold or 4.4-fold, respectively. Mechanistic studies revealed that the enhanced activity of Ni₃N/MoO₂ could be attributed to the weakened hydrogen adsorption and strengthened hydroxyl adsorption. This work provides a facile approach to design high-efficiency catalysts for hydrogen-oxidation catalysis and beyond.