Preparation of ZIF-67-derived porous Co9S8/N-doped carbon polyhedrons embedded in porous carbon nanofibers for electrochemical hydrogen storage application

The use of PAN-based block copolymers and template components like poly(methyl methacrylate) (PMMA) have been proposed to prepare porous carbon nanofibers by electrospinning. The porous Co9S8 nanomaterials can be obtained using ZIF-67 as the precursor. Combining the advantages of both strategies, herein, the nanostructures of ZIF-67-derived porous Co9S8/N-doped carbon polyhedrons embedded within porous carbon nanofibers (Co9S8-NC/PCNF) were fabricated via electrospinning technology and subsequent hydrothermal, sulfidation and carbonization processes. The electrochemical hydrogen storage behaviors of Co9S8-NC/PCNF and Co9S8-NC/CNF composite electrodes were studied for the first time. Ultimately, Co9S8-NC/PCNF revealed preferable discharge capacity of 609.5 mAh/g than Co9S8-NC/CNF and conventional Co9S8 electrodes. The ZIF-67-derived Co9S8 was responsible for the primary hydrogen storage. The special porous structure and high specific surface area of PCNF increased the conductivity, offered more electrochemical active sites and rapid channel for charge transfer. The N-doped carbon within the composite improved the electrocatalytic activity and conductivity of Co9S8. Moreover, Co9S8-NC/PCNF also demonstrated better capacity retention, HRD and kinetics properties. Accordingly, Co9S8-NC/PCNF can be considered as a promising material for potential electrochemical hydrogen storage application.