Interlaced NiS2–MoS2 nanoflake-nanowires as efficient hydrogen evolution electrocatalysts in basic solutions

Abstract

The electrocatalytic activity of transition metal sulfides is strongly correlated with the active edge sites and conductivity of the catalysts. Here we developed a hybrid nanowire structure consisting of NiS₂–MoS₂ interlaced nanoflakes by the thermal conversion of nickel molybdate (NiMoO₄) nanowire precursors. The obtained NiS₂–MoS₂ interlaced nanoflakes have sub-200 nm sizes with abundant active edge sites and defects, as well as synergistic nanoscale interfaces between NiS₂ and MoS₂ throughout the whole structure. The hetero-nanowires exhibit superior hydrogen evolution reaction (HER) catalytic activity including a low onset potential of 76 mV and a small Tafel slope of 70 mV dec⁻¹ in a 1 M KOH aqueous solution, which substantially exceeds those of most of the metal sulfide HER catalysts including individual NiS₂ and MoS₂ nanostructures in basic solutions.