Preparation Of Ni-MOF Derived Composites And Investigation Of Their Non-enzymatic Glucose Sensing Performance

At present,with the increase of diabetes patients,the market demand for glucose sensor is also increasing.Under the condition of insufficient stability of enzyme sensors,the development of non-enzymatic glucose electrochemical sensor has attracted much attention.Electrode material is the main factor affecting the performance of non-enzymatic glucose sensor.Therefore,the preparation of non-enzymatic glucose sensor electrode materials with simple synthesis process,high sensitivity,selectivity and stability is still the focus of research.In recent years,MOFs and their derivatives have shown great potential in glucose non-enzymatic sensing.The work of this master thesis aimed at the problems of poor electrical conductivity and structural stability of the currently prepared MOFs materials in aqueous solution,choosed two kinds of nickel MOFs,and carried out a series of studies on the synthesis of MOFs derivatives from the aspect of regulating and optimizing the composition and structure of MOFs.The MOFs derivatives with high catalytic activity and high conductivity were obtained,which provided the experimental basis and theoretical basis for the preparation of new glucose non-enzymatic sensing electrode materials.The main research results are as follows:(1)Ni2(BDC)2TED with hexagonal prismatic structure was synthesized by oil bath,and MOFs-derived carbon nanocomposites(Ni/NiO/NC)with nickel/nickel oxide nanoparticles uniformly distributed in a nitrogen-doped carbon frame was synthesized by annealing treatment.The results show that the structure and composition of nanocomposites can be controlled by adjusting annealing temperatures.Electrochemical analysis results demonstrate that the Ni/NiO/NC-400 composite material obtained at the annealing temperature of 400℃ has the best performance for glucose sensing,the sensitivity of 3.2518 mA mM-1 cm-2,linear range from 0.001 mM to 3.568 mM and the detection limit of 0.032 μM.At the same time,it has good selectivity,long-term stability and reproducibility,which can be used to detect the amount of glucose in the human serum.On one hand,Ni/NiO/NC-400 retains the porous framework structure of the precursor,which can effectively avoid the agglomeration of metal nanoparticles during the annealing process and provide more active reaction sites,thereby enhancing the electrochemical activity of the composites.On the other hand,synergetic mechanism between metal nanoparticles and coated thin graphene layer effectively enhances the electrical conductivity of the Ni/NiO/NC-400 composites,which improves its electrochemical performance.(2)Nickel-based Zeolitic Imidazole Frameworks(Ni-ZIF)was synthesized by solvothermal method,and the modification of Ni-ZIF with poor conductivity was studied by chemical etching and heat treatment,with its composition and structure optimized.On one hand,ultra thin transition metal hydroxides(NiCu-LDH)was prepared by in-situ etching of Ni-ZIF.The obtained porous structure is conducive to rapid ion transport.The two-dimensional layered nanosheet structure on the surface can facilitate the interlaminar insertion of ions and shorten the transport distance,and provide a larger specific surface area and more metal active sites.On the other hand,the Ni-ZIF structure was degraded into nitrogen-doped porous carbon and metal nickel nanoparticles(Ni@NC)during carbonization by heat treatment.The materials prepared by heat treatment modification have large specific surface area and layered pore structure.Among them,carbon nanotubes are formed on the surface of Ni@NC-700-3 composites obtained by optimizing heat treatment conditions,and the nickel nanoparticles are in close contact with the carbon nanotubes,which improves the conductivity of the Ni@NC composites.The results of electrochemical analysis prove that,compared with Ni-ZIF,NiCu-LDH and Ni@NC composites derived from Ni-ZIF through structure modification have significantly improved glucose non-enzymatic sensing performance.In this work,the reasonable design of modification forNi-ZIF’s structure and the comparative study on the electrocatalytic glucose oxidation mechanism of MOFs derivatives provide a strong theoretical basis for the future application of metal organic frameworks in non-enzymatic glucose sensing electrodes.