Multifunctional Ni3S2@NF-based electrocatalysts for efficient and durable electrocatalytic water splitting

Abstract

Transition-metal sulfides (TMSs) have indeed drawn dramatic interest as a potential species of electrocatalysts by virtue of their unique structural features. However, their poor stability and inherent activity have impeded their use in electrocatalytic water splitting. Here, we provide a rational design of a hierarchical nanostructured electrocatalyst containing CeO_x-decorated NiCo-layered double hydroxide (LDH) coupled with Ni₃S₂ protrusions formed on a Ni foam (NF). Specifically, the as-prepared electrocatalyst, denoted as Ni₂Co₁ LDH-CeO_x/Ni₃S₂@NF, presents only 250 and 300 mV overpotential at ±100 mA cm⁻², respectively, along with the Tafel slope values of 92 and 52 mV dec⁻¹, as well remarkable long-term life for water splitting in an alkaline electrolyte. Based on systematic experiments and theoretical analysis, the superior electrocatalytic property in terms of Ni₂Co₁ LDH-CeO_x/Ni₃S₂@NF can be imputed to the following reasons: the porous framework of Ni₃S₂@NF provides a largely surface area and high conductivity; the NiCo LDH nanosheets provide enriched active sites and favorable adsorption ability; the oxygen-vacancy-rich CeO_x optimizes the electronic configuration. Overall, these factors work synergistically to expedite the catalytic kinetics of splitting water. Our work concentrates on a rational interface to devise efficient, multifunctional, and serviceable electrocatalysts for future applications.