Engineering Functionalbility Of Porous Carbon Materails And Their Properties In Electrocatalysis

With the increasing energy crisis and environmental disruption,fuel cells metal-air batteries,and water electrolyzer technologies have been recognized as clean and efficient energy conversion or storage devices for alternatives to fossil fuels.Efficient catalysts for the oxygen reduction reaction(ORR),hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)play important roles in these renewable energy technology fields.At present,noble metals(such as platinum,ruthenium and iridium)and their alloys reveal excellent electrochemical performance for these reactions.However,high cost and shortage of resources have been the obstacles in the industrial application of these energy conversion and storage devices.Therefore,it is urgent to develop low-cost,high-activity non-noble metal based catalysts to replace noble metal catalysts.Transition-metal(Fe,Co,Ni)based metal-organic framework materials with controllable structures,large surface areas and adjustable pore sizes have attracted wide research interest in electrochemical catalysis field.Here,the Fe、Co and Ni metals are employed as metal centers to construct MOF,respectively.By adjusting the structure and composition of the ligands,the specific surface area and chemical composition of the final materials can be adjusted to optimize the catalytic performance.In this thesis,three kinds of highly efficient non-precious metal electrocatalysts were prepared.Firstly,graphene was used as substrate to improve the conductivity,ZnCo-MOF/Gr was prepared by solvothermal method,the porous carbon materials(Co-N-C)modified with Co and N were prepared by using ZnCo-MOF/Gr as template by pyrolysis.And the effect of pyrolysis temperature on catalytic performance is observed.Secondly,zinc acetate and dithiooxalamide(DTO)was used to prepare Zn-DTO MOF.To gain the highly active sites of Fe-Nx,the Fe complex with phenanthroline-iron was introduced into Zn-DTO MOF by site isolation method,then the N,S and Fe-Nx functionalized carbon material(FeNSC-900)was constructed and the surface area and chemical composition was tuned by adjusting the pyrolysis temperature.Finally,Ni-MOF was synthesized by employing Ni as metal center and 1’1-ferrocene dicarboxylic acid as ligand.The Ni and NiFe2O4 modified carbon materials(Ni-NiFe2O4/C-T)were obtained by heating at different temperature.The morphology and composition of the as-prepared catalysts were characterized by XRD,SEM,TEM,Raman and other techniques.Electrochemical measurements of the catalysts were carried out by CV,LSV,i-t and other electrochemical techniques.The results show that the prepared catalysts show excellent performance in electrochemical catalysis.