To achieve sustainable economic growth and reduce environmental pollution,countries should adhere to the concept of green economy and actively develop clean new energy.We learned that oxygen reduction and oxygen precipitation reactions?ORR/OER?play a vital role in energy conversion devices.In this study,a bimetallic composite with a stable core@shell structure based on MOFs derivatives was constructed to improve ORR/OER performance.This article were prepared two?Co3O4@Z67-NT@CeO2 and CoO@GC/WO3@CL?dual-function electrocatalysts,both of which are based on MOFs?ZIF-67?derived bimetal oxide multilayer structures,and passed a large number of Materials physical characterization methods and electrochemical?ORR/OER?performance testing methods analyze their material composition,element valence,pore size,apparent morphology,starting potential,current density and stability,etc.Mechanism makes reasonable inferences.A porous metal-doped nitrogen-carbon framework Co3O4@Z67-NT was prepared using ZIF-67 polyhedron as a precursor to a carbonization temperature of 500-900?.Then,through a simple hydrothermal process,CeO2 nanoparticles were uniformly coated on the surface of the porous Co3O4@Z67-NT substrate.The obtained Co3O4@Z67-NT@CeO2 composite material basically retains the original morphology of the ZIF-67polyhedron and exhibits excellent bifunctional?ORR/OER?catalytic activity.ORR))is0.70 V.For ORR,the half-wave potential of Co3O4@Z67-N700@CeO2 is 0.88 V?vs.RHE?,which is attributed to the synergy between CeO2(Ce3+)and Co3O4(Co2+).The rich oxygen vacancies in CeO2 can enhance theO2 on the adsorption interface,thereby promoting the activation of the adsorbedO2 toO2-,which alleviates the lack ofO2during the ORR,thereby increasing the ORR activity.For OER,Lower overpotential?350 m V?of Co3O4@Z67-N700@CeO2 at 10 m A cm-2,the Faraday efficiency is 92.2%.The effective valence state transition between Ce3+and Ce4+gives CeO2 high conductivity and oxygen storage capacity,which greatly promotes Charge transfer and the generation and smooth transportation of highly active substances(O22-/O-).In this study,the interaction between CeO2(Ce3+/Ce4+and oxygen vacancies)and Co3O4(Co3+/CoOOH)provided more electrochemically active sites for the ORR/OER process.In addition,in the presence of polyvinylpyrrolidone,WO3 microrods were evenly distributed on the surface of ZIF-67 dodecahedron.ZIF-67/WO3-MRs precursors are carbonized at different temperatures?600-1000??.WO3 spheres?at 800??wrapped from a thin layer of carbon derived from WO3 microrods are anchored in situ at ZIF-67-derived CoO Graphitized carbon on the surface to obtain CoO@GC/WO3@CL catalyst.The catalyst basically retains the dodecahedron structure,high specific surface area and porous structure of ZIF-67.For ORR,CoO@GC/WO3@CL-800 has a corrected peak potential?0.81 V vs.RHE?.The synergy between WO3?oxygen vacancy?and Co2+improves the mass/charge transfer efficiency,thereby enhancing the 4e-ORR pathway.PVP-derived CL can stably embed highly active Co2+in the GC structure,thereby improving ORR stability.For OER,at 10 m A cm-2,the overpotential of CoO@GC/WO3@CL-800 is low?330 m V?and the Faraday efficiency is 91.8%higher.The strong interaction between CoOOH(Co3+)and oxygen vacancies?WO3?can promote H2O oxidation and further promote the production ofO2.CoO@GC/WO3@CL-800 has a?E of 0.72 V,confirming its promising ORR/OER activity.In this paper,the use of MOF as a template to prepare bimetallic oxide multilayer composite materials has good dual-function?ORR/OER?catalytic activity,indicating the potential application of such catalysts in the field of electrocatalysis. |