Thiol Functionalized Carbon Nanotubes And Their Applications In Electrochemistry

Carbon nanotubes (CNTs) have been widely used in electrochemistry due to their unique structure, excellent electronic and mechanical properties. For example, construction of novel sensors and biosensors, as a catalyst support for fuel cells and so on. However, the intrinsic van der Waals interactions between the pristine carbon nanotubes make them bundles in scale and insoluble in any routine solvents. Therefore, functionalization of CNTs is required before being used in various fields. In this thesis, thiol functionalized single walled carbon nanotubes (SWCNT-PhSH) was synthesized and used to modify gold electrode for detection of environmentally harmful substance Hg(Ⅱ). Besides, the electrocatalysts, PtRu nanoparticles supported on SWCNT functionalized with carboxyl group and mercapto group (f-SWCNT), was synthesized and used for direct methanol fuel cells (DMFCs). The main research in this paper as follows:(1) SWCNT-PhSH was synthesized by diazonium reaction and characterized by thermogravimetry analysis, Fourier transform infrared spectroscopy, and Raman spectroscopy.(2) SWCNT-PhSH was covalently modified Au electrode for determination of Hg(Ⅱ). Various factors such as pH, preconcentration time, deposition potential, and deposition time influencing the determination of Hg(Ⅱ) were thoroughly investigated in this study. Under optimal conditions, the electrochemical sensor exhibited a wider linearity range from5.0nM to90nM Hg(Ⅱ) with a detection limit of3.0nM (S/N=3). This novel sensor was successfully applied to determine Hg(Ⅱ) in real water samples with good recovery, ranging from96%-102%.(3) The electrocatalysts, PtRu/f-SWCNT, was synthesized by impregnation and reduction method with sodium borohydride. Electrochemical characteristics of methanol oxidation on the catalyst was investigated via cyclic voltammetry analysis in mixed1.0M CH3OH and0.5M H2SO4solutions. The mass activity (MA) for methanol oxidation reaches433.25A g-1Pt.