NiMo/CoMoO4 heterostructure with confined oxygen vacancy for active and durable alkaline hydrogen evolution reaction

Abstract

The sluggish kinetics of electrocatalysts in the alkalinehydrogenevolution reaction (HER) is a critical challenge to attain efficientprogress in water electrolysis for carbon-neutral hydrogen production.Here, we present a high-performance and durable heterostructure ofNiMo/CoMoO4 for the alkaline HER constructed via a two-potin situ growth strategy on a nickel foam (NF). The density of activesites and the surface area of the hybrid catalyst augmented almostthree-fold compared to those of pristine CoMoO4. The heterostructurecomposed of metallic NiMo and oxygen vacancy (O-v)-confinedCoMoO(4) facilitated the H adsorption on the metallic sideand OH adsorption on the oxide side. The hierarchical hybrid catalyston 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. Theturnover frequency of 0.012 s(-1) at the overpotentialof 100 mV of NiMo/CoMoO4 is six times higher than thatof CoMoO4, 0.002 s(-1). In addition, thefabricated heterostructure is a highly durable HER catalyst at 30mA cm(-2) for 30 h. The Faradaic efficiency recordedby a gas chromatograph at 10 and 100 mA cm(-2) revealednearly 100 and 86-95% hydrogen production efficiency, respectively.