The Synthesis Of 2-methylimidazole-based MOFs-carbon Nanotube Composite And Its Application In Electrochemical Analysis

Metal-organic frameworks(MOFs)are a new class of porous materials with the characteristics of large specific surface area,controllable composition,and easy adjustment of structure.Currently,MOFs have been applied in electrochemical sensing and have been successfully used to improve the sensitivity and selectivity of electrochemical detection.How to further improve the electrochemical analysis performance of MOFs and promote the electrochemical sensing application of MOFs is very necessary.In this thesis,carbon nanotubes(CNTs)with excellent electrochemical sensing properties were compounded with two imidazole-based MOFs respectively to prepare two composite materials,and the electrochemical sensing properties and applications were deeply studied respectively.The main research work is as follows:(1)CNTs and PVP-K30 were dispersed in methanol ultrasonically,and Ni(NO₃)₂·6H₂O was added into.After 1 h strring,the mixture was mixed with 2-methylimidazole(Me IM)methanol solution,stirring for 10 min and standing at room temperature to synthesis Ni-Me IM@CNTs composite material.XRD,XPS and TGA analysis showed that Ni-Me IM framework material was successfully synthesized and formed a composite with CNTs;SEM and TEM analysis showed that a large amount of Ni-Me IM was wrapped in the mesh pores formed by CNTs and combined with CNTs closely.The electrochemical behavior of the endocrine disruptor bisphenol A(BPA)on the surface of Ni-Me IM,CNTs and Ni-Me IM@CNTs was studied.It was found that Ni-Me IM@CNTs enhanced the interface enrichment ability and oxidation signal sensitivity of BPA.and the enhancement effects of Ni-Me IM@CNTs are much higher than those of Ni-Me IM and CNTs.A highly sensitive electrochemical detection method for BPA was established,with a linear range of 1-1000n M and a detection limit of 0.35 n M(S/N=3).The method was applied to the analysis of thermal paper and plastic daily necessities,and the measurement results were consistent with HPLC.(2)CNTs and PVP-K30 were ultrasonically dispersed in methanol,and then a solid mixture of Zn(CH₃COO)₂·2H₂O and 2-methylimidazole was added.After stirring for 5minutes,the ZIF-8@CNTs composite was synthesized by standing at room temperature.XRD and XPS confirmed that Zn and 2-methylimidazole formed the ZIF-8 framework material;TGA test showed that ZIF-8@CNTs has good thermal stability;SEM and TEM images show that a large number of CNTs are intertwined and closely integrated with ZIF-8.Compared with ZIF-8 and CNTs,ZIF-8@CNTs significantly improves the electrochemical oxidation signal of p-chlorophenol(4-CP).Based on this,a highly sensitive electrochemical determination method for 4-CP was established,with a linear range of 0.1-6?M and a detection limit of 0.04?M(S/N=3).The method was applied to the analysis of sewage samples,and the measurement results were consistent with HPLC.