Fabrication And Research Of Electrochemical Sensors Based On Functionalized Multi-walled Carbon Nanotubes Electrode

Carbon nanotubes exhibit many extraordinarily attractive physical and chemicalproperties, such as the large surface area, the good ability to promote electro-transferreactions, remarkable catalytic ability. Porphyrin compounds have special π conjugatestructure so they can be widely applied in all kinds of photoelectric study. However,carbon nanotubes were easy to fall from the electrode surface, and were often lessthan the detection sensitivity. Owning to the improper control of preparationconditions, porphyrin modified electrode can not reach the desired effect. Therefore,if the carbon nanotubes were combinated to porphyrin compounds, it is expected toovercome the defects in the separate use. This composite material will have potentialapplications in photovoltaic research, biotechnology, materials science, andenvironmental and other related disciplines.The hydroxide of meso-tetraphenylporphyrin derivatives functionalized carbonnanotubes (CNTs) was fabricated in our research to explore the interaction betweenporphyrin and explosive. On this basis,5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin functionalized carbon nanotube material was prepared to rapidly andsimultaneously detect dihydroxybenzene isomers, and the mechanism was proved bythe electrochemical method, UV and density functional theory. Further, the singlehydroxyl phenyl porphyrin covalented carbon nanotube material was prepared usingchemical organic synthesis method. Meanwhile, nano silver was deposited on thesurface of porphyrins/carbon nanotube material by electrical deposition method. Thisnovel modified electrodes was applied to the research of nitro-compound. The mainresearch contents are as follows:1. The preparation of polymerized porphyrin film functionalized carbonnanotubes modified electrode and electrochemical reduction to explosivesThe hydroxide of meso-tetraphenylporphyrin derivatives functionalized carbonnanotubes (CNTs) was fabricated in our research to explore the interaction betweenporphyrin and explosive. It was turned out that in the formation of grid porphyrin film,carbon nanotubes as cruciul base materials promoted the electron transfer rate. Mostof important, the results also showed that the electrochemical response was enhanced through increasing the number of–OH substitution in porphyrin. Such informationprovides the platform for a practical strategy for rational design of the sensor ofexplosives.2. The5,10,15,20-tetrakis (4-hydroxyphenyl) porphyrin (THTPP)functionalized carbon nanotubes (CNTs) film to simultaneously detecting andisolating dihydroxybenzene isomersA novel idea on the basis of5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin(THTPP) functionalized carbon nanotubes (CNTs) film was developed to rapidly andsimultaneously detect dihydroxybenzene isomers based on their different oxidationpotentials and corresponding currents. The mechanism involved in the recognition andisolation of the dihydroxybenzene isomers was explored and confirmed by UV spectraand density functional theory. It was proven that the current method forsimultaneously detecting and isolating dihydroxybenzene isomers was ascribed to thepriority of porphyrin film to induce oxidation of the three kinds of isomers, and thepriority depends to a large extent on the different tendencies of dihydroxybenzene tointeract with the peripheral hydroxyl group and with the extended π-conjugated ringof porphyrin. Most important of all, porphyrin functionalized CNTs film allows forthe formation of well-defined interface and provides an advantageous andhigh-performance platform for the simultaneous determination and isolation ofdihydroxybenzene isomers.3. The preparation and application of Ag/porphyrin/CNTs modified electrodeThe π-donor characteristics of single hydroxyl phenyl porphyrin was grafted tothe surface of the carbon nanotubes which were treated in acidification. Compared toporphyrin, the ultraviolet spectrum of the functionalized carbon nanotubes materialredshifted, showing the porphyrin functionalized carbon nanotubes enhance theeffective π conjugate structure of porphyrins, and suggesting the single hydroxylphenyl porphyrin modified carbon nanotubes can be used to detect nitro-compound.Further, nano silver was successfully modified to porphyrin functionalized carbonnanotubes surface by the method of electrochemical deposition, and the new materialswas studied to the electrochemical response of nitro-compound. The research results show that the electrochemical response of nitro-compound was increased significantlyon modified electrodes. It is a guidance to race the development of sensor fordetection nitro-compound.