Preparation Of MOFs-based Micro-nano Structure Materials And Their Electrochemical Energy Storage And Chemical Sensing Properties

Metal-organic framework compounds（MOFs）have attracted much attention in the field of electrode modification materials for energy storage and electrochemical sensor applications due to their large specific surface area,adjustable pore structure,rich redox sites and catalytic active sites.In this work,the application of micro-nano structured MOFs and their composites in electrochemical electrode modification materials（supercapacitors or electrochemical sensors）is the research objective.The main research contents and conclusions are as follows:（1）Morphology control of MOFs and their application to electrode materials for supercapacitorsIn this work,using succinic acid as ligand,mixed metal MOFs materials were synthesized by a simple mixed solvothermal method.The prepared materials were characterized by XRD,FT-IR,SEM,XPS,and BET,and their properties as electrode materials for supercapacitors were further studied.The results show that the MOF(Ni_1.2Co_0.8)material with unique nanoflower-like morphology has a specific capacitance of 850 F·g^-1when the current density of 1 A·g^-1.The research work shows that by adjusting the ratio of Ni²⁺and Co²⁺,the electron/ion transfer inside the electrode can be enhanced,the contact resistance between the active material and the electrolyte can be reduced,and the conductivity can be improved to enhance the electrochemical energy storage activity.（2）Morphological control of Ni-MOFs and its supercapacitor performanceThe performance of energy storage materials depends largely on their structure and morphology.In this work,the morphology of Ni-MOFs（Ni‐BDC and Ni‐BTC）was controlled by different polar solvents,and their electrochemical energy storage properties were studied.The research structure shows that different solvents in solvothermal reaction can significantly regulate the morphology of Ni-MOFs,and also directly affect their electrochemical energy storage activity.The Ni-MOFs synthesized with absolute ethanol as solvent have good cycle stability,while the Ni-MOFs synthesized with DMF as solvent at the current density of 1 A·g^-1have high specific capacitance,which is related to the morphology characteristics,specific surface area and pore size distribution caused by solvent effect.（3）Synthesis of Ni-BTC@Ni₃S₄electrode material and its application to detection of dopamine（DA）At present,many single MOF sensors still have the disadvantages of poor stability and low conductivity.These objective shortcomings limit their practical application in the field of electrochemical sensors.In order to further improve the performance and practicability of MOF electrochemical sensors,a novel nanocomposite with wheat leaf morphology was synthesized using Ni-MOF material as template by in situ etching vulcanization strategy,Ni-BTC@Ni₃S₄.The synthesis strategy effectively solves the common problems of Ni₃S₄nanoparticles on the surface of MOF,such as easy aggregation,uneven distribution and unstable two-phase load.In addition,the presence of S vacancy and Ni³⁺in the Ni-BTC@Ni₃S₄composite greatly enhanced the electrochemical sensing performance for dopamine detection.The current signal of Ni-BTC@Ni₃S₄/CPE modified electrode showed a good linear relationship with the concentration of DA in the range of 0.05～750μM（R²=0.9995）.The sensitivity was 560.3μA·m M^-1·cm^-2,and the LOD value was 0.016μM.At the same time,the sensor has excellent stability and anti-interference ability.（4）Synthesis of double-ligand Zn-MOF material and its application to detection of luteolin（LUT）Solid state grinding synthesis method under room temperature has many advantages,such as simple operation,solvent-free,environmentally friendly,fast reaction,etc.In this work,1,3,5-benzenetricarboxylic acid and 4,4’-bipyridine were used as mixed-ligands to successfully synthesize nano-block Zn-MOF containing mixed ligands under room temperature by solid phase grinding reaction,and its electrochemical sensing performance was further studied.Zn-MOF modified carbon paste electrode（Zn-MOF/CPE）can be used to detect luteolin by simple,rapid and sensitive electrochemical sensing.The electrode modification material of the electrochemical sensor has reliable stability and reproducibility,and it also has excellent applicability for the analysis and detection of luteolin in real samples.The research in this paper provides a reliable theoretical and experimental basis for the preparation of nano-porous MOFs compounds and their composites for the application of electrode materials in the field of supercapacitors and electrochemical sensors.