ZIF-67-derived N-enriched porous carbon doped with Co, Fe and CoS for electrocatalytic hydrogen evolution reaction.

Hybrid composites based on transition metal-doped materials exhibit excellent performance and stability as electrocatalysts for the hydrogen evolution reaction (HER). Thus, they could easily replace HER catalysts based on noble metals. To demonstrate this, we fabricated Co, Fe, and CoS doped N-enriched porous carbon materials (CoFeS/NC) using a simple, straightforward and quick method (involving absorption, pyrolysis and sulfidation steps), which used ZIF-67 metal-organic framework (MOF) material as a precursor. The fabricated CoFeS/NC showed excellent HER performance and long-term stability: it achieved a low potential (equal to 176 mV) at 10 mA cm current density and a small Tafel slope (equal to 67.8 mV dec) in 1.0 KOH. Such outstanding HER performance was attributed to the synergistic effect of the CoFeS/NC components, including unique mesoporosity. All these properties ensured the presence of numerous active sites and high conductivity provided by the carbon matrix. The excellent CoFeS/NC electrocatalytic activity makes it a promising material for H production on an industrial scale. Our work demonstrated a simple way of its preparation, which could be applied to other material groups.