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

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, thus ameliorating their electrocatalytic properties. Here, we report for the first time a robust and earth-abundant Ni-doped Co3S4 catalyst grown on carbon cloth that showed high HER activity in 1 M KOH. The morphology evolution and HER activity are strongly related to the Ni substitution ratio. Electrochemical tests showed a low overpotential of 72.82 mV at 10 mA*cm-2, small Tafel slope of 49.44 mV*dec-1, and long-term durability over 46 h 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 the exposure of active species and transfer of electrons and charges, substantially boosting the reaction kinetics and structure stability.

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