Construction Of Metal Organic Framework Composite Materials And Study On Electrocatalytic Performance

Metal organic frameworks（MOFs）are metal-organic coordination porous crystal material composed of metal ions/metal clusters（such as Cu,Fe,Co,Ni,etc.）and organic ligands.It has the advantages of large specific surface area,adjustable structural composition,and easily functionalized channels.In recent years,MOFs and their derived composites have been widely synthesized and applied in the fields of catalysis,adsorption,and energy storage.This thesis is devoted to the preparation of transition metal-organic frameworks and their derived nanocomposites and the research on electrocatalytic sensing and electrocatalytic nitrogen fixation.The following three aspects of research work have been performed:1.Chiral C-dots（CDs）were prepared from cheap D-/L-glucose by microwave method.2-aminoterephthalic acid as the organic ligand,Ni²⁺as the central metal ion,and CDs were mixed to form an electrodeposition solution,which was then electrodeposited on a copper wire to form a chiral CDs@Ni-MOF nanoarray composite.SEM,XRD,fluorescence spectrum,circular dichroism spectrum and other detection methods were used to characterize the structure,composition and surface morphology of the synthesized chiral CDs@Ni-MOF nanoarray composites,confirming that the composite is a kind of Chiral MOF composite.Electrochemical experiments such as linear scanning cyclic voltammetry,differential pulse voltammetry,and impedance spectroscopy were performed to measure the related data of sensing oxidation/reduction peak potential,peak current and impedance.The effects of various factors on the sensing performance of the chiral CDs@Ni-MOF nanoarray composites were studied,including the pH of the buffer and the concentration of the analyte.Using D-/L-penicillamine as the test enantiomer and scanning cyclic voltammetry as the detection method,the two configurations of penicillamine were successfully identified.2、A novel Cu-MOF@SPANI was successfully synthesized by using Cu（NO₃）₂ as the metal source,H₆L as the organic ligand,and doped helical polyaniline（SPANI）.The morphological structure and composition of the Cu-MOF@SPANI hybrid material were characterized by infrared spectroscopy,SEM,XRD and other means.Experimental conditions such as material ratio and pH were optimized,and differential pulse voltammetry and impedance spectroscopy were used to determine the catalytic recognition oxidation/reduction peak potential,current density and impedance data,and successfully completed the chiral recognition of tyrosine enantiomers.3、Co（NO₃）₂·6H₂O,Fe（NO₃）₂·9H₂O were used as the coordination metal source,and2,6-pyridinedicarboxylic acid was used as the organic ligand to synthesize the cobalt-iron bimetallic MOF catalyst.XRD,SEM,etc.were performed to characterize the morphology and chemical composition of the prepared Co/Fe-MOF composites.In order to obtain Co/Fe-MOF crystals with good morphology and high catalytic activity.The synthetic Co/Fe-MOF derivative catalyst was used for electrocatalytic nitrogen fixation.The effects of nitrogen fixation conditions such as metal ratio,calcination temperature,electrolytic voltage,and electrolyte solution on the performance of the electrocatalytic ammonia synthesis of the prepared Co/Fe-MOF derivative materials were studied.Through electrochemical I-t constant potential electrolysis,AC impedance spectroscopy and other test methods,the current density and impedance of the derivative materials were obtained,the ammonia gas yield and Faraday efficiency were calculated.The excellent and optimal conditions of Co/Fe-MOF derivative materials were screened at room temperature.The results show that Co/Fe-MOF composites show more excellent catalytic performance and stability in electrocatalytic nitrogen fixation compared with single Fe-MOF and Co-MOF.