Synthesis of a Porous CoS2‐CN/MWCNTs Composite Derived from ZIF‐67 for Electrochemical Hydrogen Storage Applications

Abstract

AbstractThe porous CoS2/nitrogen‐doped carbon (CoS2‐CN) polyhedrons were prepared using metal‐organic framework as the precursor. After the carbonization of zeolitic imidazolate framework ZIF‐67 and the heat treatment with sulfur, the CoS2‐CN composite was obtained. Multi‐walled carbon nanotubes (MWCNTs) were introduced and evenly intertwined with the CoS2‐CN. Eventually, CoS2‐CN and Co‐CN exhibited good discharge capacities of 498.3 mAh/g and 402.2 mAh/g, respectively. For electrochemical hydrogen storage, more electrochemical active sites could be provided owing to the extraordinary porous nanostructure and large specific surface area inherited from ZIF‐67. The N‐doped carbon could enhance the conductivity of the materials. The CoS2‐CN electrode revealed higher discharge capacity than Co‐CN due to the introduction of sulfur species. Moreover, the discharge capacity further increased to 542.8 mAh/g for CoS2‐CN/MWCNTs. The loaded MWCNTs could further enhance the conductivity and electrocatalytic activity of CoS2‐CN. The high‐rate dischargeability, kinetic properties and corrosion resistance were also improved after MWCNTs modification.