Microspheric flower-like Co 4 S 3 @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.