Study Of Electrochemical Sensing Based On MOFs Composites

Since the Metal-Organic Frameworks(MOFs) materials put forward in the last ten years, this field has seen an amazing development. The structure of the MOFs is composed of a metal ion cluster as a node, and an organic-inorganic crystal material formed by the connection of the metal ion and the organic ligand bridge, so the common advantages of both organic and inorganic materials are combined. Compared with the traditional porous materials, MOFs is a new crystal material with porous structure and is currently found to possess a large specific surface area among the other material, and with a regular pore size, high porosity, has a high density of metal active sites, good stability and highly ordered, easily modified and good catalyticpropoerties, based on these characteristics it has got potential applications in gas separation and storage, catalysis and sensor field. Therefore, taking the advantage of the above mentioned properties, novel electrochemical sensors can be developed using MOFs and its composites. At present, there are some reports describe the electrochemical sensors based on MOF, their weak electrical conductivity and the less exposure of active site limit its application in the field of electrochemical sensing. In this paper a more classical Co based MOFs(ZIF-9) has been combined with highly conducting carbon materials and heterocyclic porphyrins to overcome the MOFs weak conductivity and to well expose the active site then it been used as an electrochemical sensor for nitrobenzene(NB) and glucose(GL). This paper mainly consists of the following parts.Chapter 1 IntroductionReview of the recent literature on MOFs preparation, their research progress in the field of electrochemical sensors. Introduction to carbon, porphyrin composites and their preparation has been presented. Finally the aim, objectives, research significance and innovation of this study has been discussed.Chapter 2 5, 10, 15, 20- four(4- carboxyl phenyl) porphyrin and its metal complexes synthesis and characterization5, 10, 15, 20 tetra(4-carboxyphenyl) porphyrin(TCPP) and its metal complexes were synthesized using aldehyde, benzoic acid and methyl ester. Compared to the synthetic procedure of 4-carboxybenzaldehyde, this method is better in terms of yield and separation and purification process. Nuclear magnetic resonance hydrogen spectrum, infrared spectrum, UV-vis spectroscopies were used to characterize the synthesized porphyrin. At the same time, the method for the synthesis of double metal MOFs is possible using TCPP as a ligand for the preparation of double metal MOFs possible.Chapter 3 Study on the preparation and electrochemical properties of MWCNTs@Co-MOFs/GNIn this chapter, a new material of MWCNTs@Co-MOFs/GN was synthesized and characterized by SEM, TEM, EDS, FT-IR and other techniques. Multiwalled carbon tubes(MWCNTs) insertion into the MOFs resulted in the considerable increase in conductivity of the resultant material and its active sites have been exposed. Then MWCNTs@CoMOFs was loaded onto graphene(GN), to further improve the conductivity of MOFs. MWCNTs formed the network structure with GN to further increase the transport of electron and ion which in turn enhanced the catalytic activity of the MOFs to achieve a good electrochemical detection of NB.Chapter 4 Study on the preparation and electrochemical properties of CoTCPP/MWCNTs@Co-MOFsIn this chapter, the new material of Co-TCPP/MWCNTs@Co-MOFs was synthesized, and the metal porphyrin was introduced into the MOFs by the use of the MWCNTs to expose the active sites. A new type of non-enzymatic electrochemical sensor was prepared by the inclusion of porphyrin in MOFs, and the new type of non-enzymatic electrochemical sensor was prepared by the action of metal porphyrin.