Ternary NixCo3-xS4 with a Fine Hollow Nanostructure as a Robust Electrocatalyst for Hydrogen Evolution

The elaborate design of efficient and stable electrocatalysts from earth-abundant elements to replace precious Pt for the hydrogen evolution reaction (HER) is an ongoing challenge. Doping metallic compounds with additional metal atoms provides the opportunity to tune their electronic and crystal structures, which thus ameliorates their electrocatalytic properties. Herein, we report for the first time a robust and earth-abundant Ni-doped Co3S4 catalyst grown on carbon cloth that shows high HER activity in 1m KOH. Morphology evolution and HER activity were found to be strongly related to the Ni substitution ratio. Electrochemical tests showed a low overpotential of 72.82mV at 10mAcm(-2), a small Tafel slope of 49.44mVdec(-1), and long-term durability over 46h HER operation for the Ni0.5Co2.5S4 nanotube array self-standing on carbon cloth. These data indicate that atomic modulation of Ni plays an important role in optimizing the morphology and electrocatalytic activity by greatly expanding the active sites in the electrocatalyst. Further, the 3D self-standing nanotube array highly aids in the exposure of active species and the transfer of electrons and charges, which substantially boosts the reaction kinetics and stability of the structure.