Preparation Of Cobalt-based Microstructured Carbon Fibers And Their Electrocatalytic Properties Study

With the increasing consumption of traditional fossil fuels,develop new clean energy to replace traditional fossil fuels.The research work of materials is imminent.In order to improve a series of environmental problems caused by traditional fossil fuels,people will focus on hydrogen energy.Hydrogen has high energy density,sustainable development and good environmental performance,which is an excellent alternative to traditional fossil fuels.Among many hydrogen production methods,the electrocatalytic water cracking reaction stands out by virtue of its large hydrogen production scale and fast rate.Electrocatalytic water lysis can be divided into hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）.However,these hydrogen-and oxygen-based electrochemical reactions are always limited by slow kinetics,which greatly reduces the energy conversion efficiency of the system.Therefore,the development and design of efficient catalysts plays a key role in promoting the development of clean energy conversion systems.Based on this,through the molecular design of the precursor and the structural design of the carbon matrix,the tight composite of cobalt-based compounds and carbon nanotubes was realized,and then a series of cobalt-based microstructure carbon fiber composites were synthesized,and their electrocatalytic properties were investigated.The main study contents and results are as follows:（1）PAN/ZIF-67 nanofibers were obtained by electrospinning,and PAN/ZIF-67nanofibers were further treated in a tube furnace to prepare CNF@Co-CNTs composite nanofibers.The one-dimensional structure of CNF@Co-CNTs can increase the electrochemical active surface area and expose more active sites.CNF@CoSe₂-CNTs composite nanofibers were prepared in a tubular furnace for selenization.In the 1 M KOH electrolyte,the composite nanofiber was only 373 m V at a current density of 10m A cm^-2,with a Tafel slope of 93.7 m V dec^-1.After cycle testing,it shows good stability,which shows that CNF@CoSe₂-CNTs composite nanofiber has good electrocatalytic oxygen evolution performance and a good application prospect for the direction of electrolysis water oxygen evolution.（2）PAN/ZIF-67 nanofibers were obtained by electrospinning,and PAN/ZIF-67nanofibers were further treated in a tubular furnace to prepare CNF@Co-CNTs composite nanofibers.Then it was placed in a tubular furnace for phosphating to prepare CNF@CoP-CNTs.When the current density is 10 or 50 m A cm^-2,the overpotential of CNF@CoP-CNTs composite nanofibers is only 280 or 367 m V,and the tafel slope is 126.1 m V dec^-1,and it has good durability,at the same time,its HER performance is also significantly improved.With a current density of 10 m A cm^-2,the overpotential is only 65 m V and the Tafel slope is 80.7 m A dec^-1,which also has good durability.This study shows that CNF@CoP-CNTs nanofibers with one-dimensional structure have excellent electrocatalytic properties.