The Design And Application Of Electrochemical Sensors Based On Metal Organic Frameworks And Their Derivatives

In the past few decades,the research on the synthesis and application of Metal Organic Framework（MOFs）has been greatly developed.Among the reported porous materials,MOFs with unique properties provide a promising platform for electrochemical sensing.The high porosity,large number of exposed active sites and large specific surface area of MOFs materials provide a location for supporting guest molecules and highly catalytic metal particles,and improve the sensitivity for electrochemical detection.The controllable pore size can control the matrix of the MOFs material to select specific analytes exclusively and improve the selectivity.These advantages make MOFs equipped with electrochemical sensors widely used in various applications,including environmental monitoring,food quality control,medical diagnosis and chemotherapy treatment detection.Although MOFs are an electrochemical sensor electrode material with excellent performance,some MOFs have poor conductivity and stability,which limit their application in electrochemical sensing.To overcome these issues,developing MOF based hybrid or derived composite is an efficient way.In this thesis,we fabricated several three dimensional porous carbon based hybrid based on graphene or MOF derived carbon for developing sensitive electrochemical snesors.The research content of the thesis includes:1.In this work,a core-shell MOF derived hybrid NC@Co-NGC was developed for electrochemical detection of catechol（CC）and hydroquinone（HQ）.First,ZIF-8@ZIF-67 was prepared by using ZIF-8 as the core and wrapping ZIF-67 in the outer layer.Hollow nanocage NC@Co-NGC materials were prepared by high-temperature carbonization.The structure of the product was charicaterized by SEM,TEM and so on.Electrochemcial investigation revealed nitrogen-doped three-dimensional porous carbon faciliated electron transfer,while Co improved the catalysis.The NC@Co-NGC displayed good catalysis for HQ and CC,which can be used to detect both of them separately and simultaneously without interfering with each other.The linear range of the electrochemical sensor for detection of CC is 5-750μM,and the detection limit is 1.3μM;the linear range of HQ detection is 5-750μM,and the detection limit is 1.3μM;both CC and HQ are detected The linear range of the detection range is 3-1500μM,and the detection limit is 1.3μM.2.In this work,a sensitive H₂O₂ electrochemcial sensor was constructued based on Co-doped MOF derived porous carbon hybrid C@Co.High-density MOFs material MET-6 was synthesized using triazole as a ligand,and then MET-6@Co was prepared by doping Co.Using MET-6@Co as a precursor,a Co-doped layered porous three-dimensional porous carbon network material C@Co was prepared.Compared with a separate three-dimensional porous carbon material,a three-dimensional porous carbon network with layered porosity can provide as many electron channels as possible to achieve rapid electron transport to fully utilize the catalytic activity of cobalt nanoparticles.The experimental results show that by electrochemical testing we found that the modification of C@Co on GCE shows good catalytic activity for H₂O₂.The linear range is from 0.4μM to 23μM,and the detection limit is 0.13μM.3.In this work,a heavy metal ion electrochemical sensor was fabricated by growing a composite of UiO-66 and bismuth nanoparticles（BiNPs）on a 3D multi-stage porous graphene（3DHGO）aerogel.Firstly,hydrogen peroxide（H₂O₂）was used to corrode graphene oxide to prepare 3DHGO aerogel.UiO-66 was grown in situ on 3DHGO aerogel by hydrothermal method.Finally,BiNPs were grown on the surface of UiO-66 by reduction.Composite material 3DHGO/UiO-66@BiNPs.We used scanning electron microscope SEM and transmission electron microscope TEM techniques to characterize the morphology of 3DHGO/UiO-66@BiNPs materials.The electrochemical method was used to study the ability of 3DHGO/UiO-66@BiNPs to detect heavy metal ions Cd²⁺and Pb²⁺.The experimental results show that the linear range of the electrochemical sensor for Cd²⁺detection is 0.02μM-4μM and the detection limit is 0.007μM;the linear range of Cd²⁺detection is0.02μM-4μM and the detection limit is 0.008μM;for Cd²⁺The detection range of Pb²⁺and Pb²⁺is 0.04μM-4μM,and the detection limit is 0.012μM.