Design And Electrocatalytic Performance Of Self-supporting Electrodes Based On ZIFs And Their Derivatives

Facing the increasingly serious energy crisis and environmental pollution problems,building a clean and efficient new energy system has become an inherent requirement for achieving sustainable development.Among the many renewable energy sources,hydrogen energy has attracted much attention because of its environmental friendliness,cleanliness,high efficiency,and wide range of applications.It stands out as a very promising new energy form.Among them,the electrolysis of water to produce hydrogen is a very promising way of producing hydrogen.In addition,in the field of energy storage and conversion,zinc-air batteries are attracting attention as a new type of electrochemical energy storage device,with high energy density,low environmental pollution,and low price,which are suitable for large-scale commercial popularization.However,the electrocatalytic reactions involved in these new energy forms and devices(such as the hydrogen evolution reaction HER and oxygen evolution reaction OER for hydrogen production by electrolysis of water,the oxygen evolution reaction and oxygen reduction reaction ORR of zinc-air batteries)are subject to highly efficient and stable catalysts.Traditional commercial Pt-based and Ru-based precious metal catalysts are difficult to apply on a large scale due to their high price and limited reserves,which limits the commercialization and popularization of electrolyzed water hydrogen and high-efficiency zinc-air batteries.Among the numerous non-precious metal materials,transition metals and carbon materials have been extensively studied because of their superior performance comparable to precious metal catalysts.Among them,zeolite imidazole ester framework materials(ZIFs)and layered double hydroxides(LDHs)have incomparable advantages in structure and performance,and become the preparation of non-precious metal electrocatalysts to efficiently and stably catalyze ORR/OER/HER reactions.Important precursor materials.In addition,in order to avoid the inevitable binder usage and dead volume problems of traditional powdered catalysts,this paper uses the above two materials as the basis,and prepares two kinds of materials for the complete solution by adjusting the composition and morphology design.As a self-supporting high-efficiency catalyst for air electrodes of water and zinc-air batteries,the formation mechanism of the catalyst and the relationship between its structure and electrochemical performance were discussed,and a new possible way was verified for the design of electrocatalysts using ZIF and LDH as precursors.The main research contents of this paper are as follows:(1)Using foamed copper(CF)as a self-supporting substrate and in-situ growth of Cu(OH)₂ nanowires as a template,Co Zn-ZIF nanocrystals are grown on the surface and the size is adjusted,and then undergoes a rapid hydrothermal process.The growth process of conventional LDH was changed to prepare highly ordered hollow Cu O@Co Zn-LDH nano-arrays with abundant defect holes on the surface.The resulting divided nanostructures can provide a larger surface area and expose more active sites,and have better mechanical stability.The catalyst exhibits excellent HER,OER and total water dissolution performance in 1.0 M KOH electrolyte and good cycle stability.(2)On carbon cloth(CC)as a self-supporting substrate,two-dimensional Co/Zn-based ZIF-L is grown in situ as a precursor,and then ion exchange and etching reactions are carried out with Ni(NO₃)₂ to obtain a Ni Co Zn-LDH hollow structure,And then through simple pyrolysis to obtain a highly ordered three-dimensional cluster array of N-doped bamboo carbon nanotubes(Co Ni/N@CNT/CC)wrapped with Co-Ni bimetallic nanoparticles,which is directly used as air The cathode is used in zinc-air batteries.The three-dimensional cluster array presents an extremely ordered layered porous structure,which can significantly promote mass transfer and electron transfer,and improve the utilization efficiency of active sites.This catalyst exhibits excellent catalytic activity and stability in OER,ORR and zinc air batteries.