Microspheric flower-like Co₄S₃@Co foam synthesized by in situ sulfidization for electrocatalytic hydrogen evolution reaction

Non-noble metal sulfide electrocatalysts have received increasing attentions for hydrogen evolution reaction (HER). In this work, a facile one-step in situ sulfidization strategy was developed for the first time to construct microspheric flower-like Co₄S₃@Co foam with excellent HER activity. In comparison with the bare Co foam, the in situ growth of microspheric flower-like Co₄S₃ on Co foam substrate substantially improves the HER performance, leading to a lower overpotential of 143 mV at a current density of 10 mA cm⁻², a smaller Tafel slope of 158 mV dec⁻¹, as well as good stability in alkaline medium. The enhanced HER performance could be mainly attributed to the synergistic effects of the well-dispersed catalytic microspheric flower-like Co₄S₃ and the three-dimensional (3D) porous Co foam substrate. The microspheric flower-like Co₄S₃ is beneficial for increasing the active surface area to expose more active sites, and the intimate contact between Co₄S₃ and Co foam facilitates the electron transport, thus enhancing the catalytic activity.