NiMo/CoMoO 4 Heterostructure with Confined Oxygen Vacancy for Active and Durable Alkaline Hydrogen Evolution Reaction

High Resolution Image Download MS PowerPoint Slide The sluggish kinetics of electrocatalysts in the alkaline hydrogen evolution reaction (HER) is a critical challenge to attain efficient progress in water electrolysis for carbon-neutral hydrogen production. Here, we present a high-performance and durable heterostructure of NiMo/CoMoO 4 for the alkaline HER constructed via a two-pot in situ growth strategy on a nickel foam (NF). The density of active sites and the surface area of the hybrid catalyst augmented almost three-fold compared to those of pristine CoMoO 4 . The heterostructure composed of metallic NiMo and oxygen vacancy (O v )-confined CoMoO 4 facilitated the H adsorption on the metallic side and OH adsorption on the oxide side. The hierarchical hybrid catalyst on NF featured a low overpotential of 102 mV at 10 mA cm –2, approaching that of platinum on carbon (83 mV) in 1.0 M KOH. The turnover frequency of 0.012 s –1 at the overpotential of 100 mV of NiMo/CoMoO 4 is six times higher than that of CoMoO 4, 0.002 s –1 . In addition, the fabricated heterostructure is a highly durable HER catalyst at 30 mA cm –2 for 30 h. The Faradaic efficiency recorded by a gas chromatograph at 10 and 100 mA cm –2 revealed nearly 100 and 86–95% hydrogen production efficiency, respectively.