Controllable Preparation Of Cobalt-based Nanomaterials And Their Application In Water Electrolysis

The Cobalt-based catalyst is one of the important catalysts for water electrolysis,but large cobalt particles do not perform well in the process of catalytic reaction.In contrast,nanomaterials have higher surface area and better catalytic efficiency.Among nanomaterials,cobalt-based nanomaterials have attracted widespread attention,mainly due to comparing with other nanomaterials,cobalt-based nanomaterials have better catalytic activity and efficiency,such as high hydrogen and oxygen yield,low initial potential and smaller polarization.Moreover,the improvement of the preparation process,cobalt-based nanomaterials can be manufactured in a more controllable manner and their shapes can be customized.This controllability can be adjusted by shape,size,surface properties,etc.,to suit a variety of application scenarios.Therefore,the controllable preparation of cobalt-based nanomaterials and their application in the process of water electrolysis are studied in this subject,which mainly includes the following parts:（1）In the first part,CoMoO₄@CoFe-LDH/NF nanolayered heterostructures were prepared on foam nickel substrate（NF）by means of hydrothermal and electrochemical deposition.Co Mo O₄@Co Fe-LDH/NF shows good electrolytic oxygen evolution performance in alkaline environment.It can achieve a current density of 10 m A cm^-2at an overpotential of only 245 m V,and has a turnover frequency of 0.2560 s^-1at an overpotential of 200 m V.In addition,the nanolayered structure of the catalyst can still exist after working for 47 h,which can provide a reasonable and controllable idea for the construction of novel cobalt-based nanomaterials.（2）In this part,Cr-CoP/NF curved nanosheet structures were prepared by introducing chromium atoms into the organometrics framework（MOF）as directional templates,which were used as catalysts for hydrogen evolution reaction in electrolytic water.The results show that the catalyst only needs 46 m V overpotential at the current density of 10 m A cm^-2,and the catalyst can maintain stability no matter after 1000 cycles of voltammetry or after a long time stability test,indicating that the catalyst has excellent electrolytic water hydrogen evolution performance and durability.（3）In this part,we first prepared Co（OH）F/NF as the core precursor by hydrothermal method,then used Prussian blue-like material（PBA）as the induction template to obtain the shell precursor,and finally obtained Fe Co S₂@Co S₂/NF core-shell heterogeneous structure by low temperature phosphatizing as the catalyst for electrocatalytic total hydrolysis.Due to the advantages of using PBA as the induction template and core-shell heterostructure,the catalyst showed satisfactory performance in the process of hydrogen evolution and oxygen evolution in electrolytic water.In addition,when we use Fe Co S₂@Co S₂/NF as positive and negative electrodes to assemble a two-electrode system for complete hydrolysis experiment,ahe current density of 10 m V cm^-2requires only 1.50 V voltage and can be continuously reacted for a long time without a significant drop in voltage This can be to build other high efficiency,low cost of heterostructure catalyst for new ideas and inspiration.