Preparation And Electrocatalytic Performance Of N-rich Porous Carbon Material Co-based ZIF-67

With the great process of building China into a modern socialist country and the rapid and stable progress of industrialization,environmental pollution has become more and more serious.At the same time,the demand for energy has risen sharply due to changes in human lifestyle and population growth.Fossil energy,as the main fuel consumed by human beings,is non-renewable.Therefore,it is of great importance and historical significance to develop new energy,find alternative solutions for sustainable energy,and combine green energy and energy storage system.Porous carbon compounds as new catalyst materials have practical research significance to improve the catalytic efficiency of reaction.Due to its controllable porous structure,specific surface area,electrical conductivity and stability,it can promote the accessibility of the active site,accelerate the electronic conductivity of the whole electrode,and improve the catalytic ability of the composite.Therefore,porous carbon materials have a good application prospect in electrochemical field.In summary,this paper designed and prepared a series of porous carbon composite catalysts based on metal-organic framework porous carbon materials,which can be used in electrochemical applications such as energy conversion or storage,and studied their composition and morphology in order to understand the catalytic process and mechanism.The main research work is as follows:（1）The precursor ZIF-67 porous carbon matrix material was synthesized at room temperature.The crystallinity,crystal size,morphology and other microstructure of the synthesized ZIF-67 crystal material were studied by XRD,SEM and other characterization methods.It is found that methanol content and the ratio of metal to organic ligand have significant influence on crystallinity and crystal size.The synthesis of ZIF-67 with higher crystallinity,regular morphology and uniform size can be accelerated by increasing the amount of organic solvent and organic ligand.（2）CoNi/NC and CoNiMo/NC were synthesized as catalytic materials under vacuum condition by a series of optimal scheme design,and different nickel sources were prepared according to the actual situation.Through comparative analysis,the results show that:Although nickel chloride and nickel sulfate can quickly synthesize rhombohedral nanomaterials with relatively regular shape,their electrocatalytic performance is limited to some extent.When another non-precious transition metal element molybdenum is added to them,their catalytic activity still does not have long-term stability.Therefore,the preparation scheme of these two nickel sources for electrocatalyst needs to be optimized.（3）Finally,zeolite imidazoline framework（ZIF-67）was used as the precursor,and porous carbon doped with Co,Mo and S was prepared by absorption and pyrolysis under vacuum conditions.The synthesized samples were characterized by XRD,SEM,TEM and XPS,and the hydrogen evolution activity was studied by electrochemical test.The results show that CoMoS/NC has better electrocatalytic performance than Co/NC and Co Mo/NC.The overpotential of CoMoS/NC is 172m V at 10m Acm^-2,and the slope of Tafel is 67.8m Vdec^-1.The doping of Co,Mo and S can be used as active sites in HER reaction process to promote charge transfer.Its multiple active sites and unique structure ensure the excellent performance of the material CoMoS/NC.