Preparation And Application Of Electrocatalyst Based On Cobalt-based Metal-organic Frameworks For Water Splitting

With the development of the energy field and the growth of social demands,energy consumption is increasing day by day,and more and more attention is paid to the development of clean energy.Electrolyzed water can produce clean H₂ and O₂,which can not only solve energy wasting but also take into account environmental protection.The electrolysis of water has two half reactions,namely the oxygen evolution reaction（OER）and the hydrogen evolution reaction（HER）.Since the kinetic process of OER is very slow,it is necessary to use high-efficiency catalysts to make its kinetic process more quickly and improve the efficiency of hydrogen production by electrolysis.Under these conditions,the development of high-efficiency catalysts for oxygen evolution reaction is currently the primary task of realizing the industrialization of water electrolysis.Metal-organic frameworks（MOF）materials are synthesized by metal ions and organic ligands.Its characteristics are very useful,such as large specific surface area,easy control of morphology and structure,regular pore-structures.However,this type material currently also has some problems,such as low conductivity and its structure is easy to collapse,etc.These problems limit application of MOF-catalyst.The purposes of this project:（1）Taking advantage of the unique structural diversity and porosity of the metal-organic frameworks to carry out in-depth development of oxygen evolution catalysts;（2）Reducing the shortcomings of the poor conductivity of metal-organic frameworks materials by taking carriers;（3）The active sites of material can be fully exposed by post-process of MOF,and the number of active bits can be increased.Thereby we can develop a more efficient metal organic frameworks-based catalyst.In this study,the cobalt-copper-based bimetallic organic frameworks was used as the research object.The non-precious metal catalysts based on the cobalt-copper-based MOF were applied to electrocatalytic oxygen evolution reactions.This paper include the following three chapters:（1）Three kinds of MOFs were prepared in this section,namely Cu-MOF,Cu/Co-MOF and CuCo-MOF.Under the condition that the source of the ligand and the metal ion are same,the research is carried out on single metal MOF,bimetal MOF and copper-plated single metal MOF.MOF are prepared by hydrothermal method,and copper ions are loaded on the Co-MOF by electrodeposition method.Finally,the physicochemical characterization of the CuCo-MOF is used to study the reaction mechanism and internal structure of the material.（2）Preparing MOF and Mo S₂ by hydrothermal method,and then taking Mo S₂ to bimetal MOF by mechanical grinding method to make composite materials.At the same time,the longer distance between the particulate MOF leads to an increase in the surface active area of the reactants.Thereby the catalytic activity of the material can be better.（3）Synthesizing a carbon material containing bimetallic oxide with the ordered nanostructure through three steps.Firstly,a bimetallic MOF with nanowire shape is prepared by self-assembly reaction,and then MOF is used as a self-sacrificing template to prepare MOF-600 that retaining the original carbon skeleton;then,the carbon confinement effect is used to form a uniformly dispersed MOF.Two metal oxides have complex synergistic effects in the OER process,and obtaining the good catalytic effects.This subject takes different methods to prepare non-precious metal catalysts that based on cobalt-copper-based bimetallic organic frameworks,which can produce the OER catalysts with highly efficient,great stability,low-cost and so on.From single MOF to composite materials to derivatives of MOF materials,through the preparation of oxygen evolution catalyst provides some new ideas of OER catalyst in the future.