Preparation Of Cobalt-based Catalytic Material And Research On Its Electrocatalytic Performance

The rapid development of human society has brought many energy problems.The increasing depletion of petroleum resources and its harm to the environment make it impossible to become the main form of energy in the future society.From a development perspective,the technology of PEMFC is a more effective and meaningful energy solution than lithium batteries and photovoltaics.However,the high cost of PEMFC makes it a long way to go to commercialization.The main cost is still concentrated on the use of a large amount of expensive platinum-based noble metal catalysts in the oxygen reduction reaction.So the development of a highly efficient non-metal catalyst is very important,which will greatly accelerate the process of its industrialization.This thesis is fouce on making ZnCo-BZIF,and then dispersing iron salt into the pores of ZIF,obtaining non-noble metals in nitrogen-doped carbon materials through high-temperature pyrolysis.Using TEM,XRD,SEM,XPS and other characterization methods to explore the changes of phase structure and shape in the synthesis process.The following is an overview of the research on this subject:1.The synthesize of ZnCo-BZIF is using the method of stirring in the room temperature,and then selecting the optimal experimental conditions through comparative experiments.It is found that the sample obtained under the conditions of pyrolysis temperature in 900℃,pyrolysis time in 2 hours and heating rate in 3.5℃/min could receive the better oxygen reduction activity.Then selecting the optimal ratio of zinc to cobalt,it is found that the sample with the best oxygen reduction performance is Zn1.25Co-N-C.So dispersing Zn1.25Co-BZIF in n-hexane solution by ultrasonic,then adding FeCl3 aqueous solution,and obtaining a sample with excellent oxygen reduction activity in high temperature pyrolysis,its performance is slightly higher than that of commercial Pt/C catalyst.XRD,TEM,XPS and other characterization methods show that the reason for its high activity lies in the existence of active sites such as Fe/Co-N.2.Using a series of operations to prepare(FeCo)xZn/N/C series catalysts by solvothermal method,ligand exchange method,and high temperature pyrolysis method,and using electrochemical test method select samples with excellent performance.It is find that the the sample under the conditions of pyrolysis temperature in 900℃ and pyrolysis time in 2 hours could the better oxygen reduction performance,which provides a certain idea for the development of subsequent experiments.3.Replacing cobalt acetylacetonate(Ⅲ)with cobalt acetylacetonate(Ⅱ),and synthesizing the hollow polyhedron of FexCoZn/N/C by solvothermal method,ligand exchange method,and high temperature pyrolysis method.Among them,Fe0.5CoZn/N/C has the highest performance,the half-wave potential(E1/2)is 4 mV higher than commercial Pt/C under the same test conditions,and its accelerated deactivation stability is also good.Through XRD,TEM,SEM,XPS,UV and other characterization methods,it is proved that its high activity and good stability are due to its good hollow polyhedron configuration and the coordination environment in which Fe and Co are dispersed.