A stable N-doped NiMoO₄/NiO₂ electrocatalyst for efficient oxygen evolution reaction

Recently, there has been a significant interest in the study of highly active and stable transition metal-based electrocatalysts for the oxygen evolution reaction (OER). Non-noble metal nanocatalysts with excellent inherent activity, many exposed active centers, rapid electron transfer, and excellent structural stability are especially promising for the displacement of precious-metal catalysts for the production of sustainable and "clean" hydrogen gas through water-splitting. Herein, efficient electrocatalyst N-doped nickel molybdate nanorods were synthesized on Ni foam by a hydrothermal process and effortless chemical vapor deposition. The heterostructure interface of N-NiMoO₄/NiO₂ led to strong electronic interactions, which were beneficial for enhancing the OER activity of the catalyst. Excellent OER catalytic activity in 1.0 M KOH was shown, which offered a small overpotential of 185.6 mV to acquire a current density of 10 mA cm^-2 (superior to the commercial benchmark material RuO₂ under the same condition). This excellent electrocatalyst was stable for 90 h at a constant current density of 10 mA cm^-2. We created an extremely reliable and effective OER electrocatalyst without the use of noble metals by doping a nonmetal element with nanostructured heterojunctions of various active components.