Preparation And Electrocatalytic Properties Of Metal-Organic Framework Composites

In order to alleviate energy security and environmental problems,clean and efficient energy conversion technology has attracted extensive attention and research.Fuel cell,water splitting and metal-air batteries are all green energy conversion technologies.Oxygen evolution reaction（OER）and oxygen reduction reaction（ORR）are important reactions in energy conversion technology.Both the oxygen reduction reaction and oxygen evolution reaction have the problems of slow kinetics,so cheap and good catalysts are needed to improve the reaction efficiency.Owing to their high surface areas,tunable pore sizes and capability for functionalization,MOFs materials can be used as electrocatalysts in these fields.In this paper,we prepared MOF-conductive polymer composites and MOF-carbon composites,where MOFs provides electrocatalytic active sites and conductive polymer film or carbon material promotes electron transfer in the composites.Composites have both electrocatalytic activity and electrical conductivity.This paper mainly studies the electrocatalytic properties of MOFs composites.The main research contents are as follows:1.Synthetise nanoscale Zr-porphyrin MOF,PCN-222（Fe）.PCN-222（Fe）nanoparticlesweredispersedintoPEDOT:PSS[PEDOT=poly（3,4-ethylenedioxythiophene）,PSS=polystyrenesulfonate]aqueous solution,and uniformly dispersed suspension was obtained by ultrasound.The uniform suspension was coated on the glassy carbon electrode and dried at room temperature.Then the film is treated by acid to improve the conductivity.PCN-222（Fe）and PCN-222（Fe）/PEDOT:PSS films were characterized by XRD,FT-IR,UV-Vis,SEM,ICP-MS,EA and electrochemical test,and the electrochemical tests showed that the synergistic effect of MOF and conductive polymer film increased the ORR half wave potential of the composite film by 112 m V.2.Ni-MOF-74 was synthesized by solvothermal method.Ni-MOF-74 and carbon black were added into ethanol solution in the ratio of 2:1,and the mixed solution was ultrasonicized.Then the mixed solution was dropwise coated on carbon paper and dried at room temperature to obtain Ni-MOF-74/C composite.Ni-MOF-74 and Ni-MOF-74/C were characterized by N₂adsorption,SEM,ICP-MS,XPS,EA and electrochemical test.The electrocatalytic results show that Ni-MOF-74/C has better OER performance,and its overpotential is 26 mV lower than that of Ni-MOF-74.