Fabrication And Properties Of Carbon-based Composite Modified Electrodes

Titanium dioxide nanotube arrays (TiO2NTs) is a photoelectric active materialwith high stability, highly ordered structure and good recyclability. However, itsinherent defects such as poor conductivity and low adsorption capacity to organicshave limited the broader application. Similarly, the conductivity and adsorptioncapacity to objects are great of importance to the performance of sensors.Carbon materials based on carbon nanotubes (CNTs) and graphnen have attractedgreat attention due to their excellent properties in electrical and mechanical.In this thesis, the composites based on carbon nanotube or graphene weredesigned and fabricated onto titanium dioxide nanotube arrays or glass carbonelectrodes. The properties of the modified electrodes were investigated. The mainstudies were listed as below:(1) Preparation, characterization, and application of the reduced grapheneoxide/Ag nanoparticle co-decorated TiO2nanotube arrays (RGO/Ag-TiO2NTs):TiO2NTs modified with RGO/Ag nanoparticles were fabricate by a simple one-stepelectrochemical deposition method in a solution contained GO-Na3[Ag(S2O3)2]-PBS(pH=9.18) by using a cyclic voltammetry (-1.5-0.5V at a scan rate50mV/s). Thestructure, catalytic activity and stability of the photocatalyst have been investigated.The results show that the catalyst achieved93%degradation rate of2,4-D under thesimulated solar light irradiation with good stability and easy recovery at the optimizedcondition of17cycles numbers and o.5mM Na3[Ag(S2O3)2].(2) One-step method for fabricating carbon nanotube film uniformly on thesurface of TiO2NTs has been proposed：CNTs functionalized by mixed acid weredispersed in PBS (pH=9.16) to get a homogeneous dispersion. By using thisdispersion as the electrolyte, a three-electrode system and CVs method (-1.5V-0.5V ata scan rate50mV/s) were carried out to deposit CNTs on the surface of TiO2NTs. Thethickness of CNT film was controlled by cycle number. The Fe(CN)3-/4-6probe andimpedance date showed that the conductibility of the modified TiO2NTs improvedsignally.(3) Fabrication, characterization and application of carbon nanotube/graphenecomposite modified glass carbon electrode: hydrophobic CNTs were dispersed well inthe GO-PBS (pH=9.18) using the amphiphilic graphene oxide as surfactant; By using this dispersion as the electrolyte, a three-electrode system and CVs method (-1.5-0.5Vat a scan rate50mV/s) were carried out to deposit RGO-CNTs composite on thesurface of glassy carbon electrode (GCE); Under the optimal experimental conditions,the stripping peak current of hydroquinone (HQ) was found to be linear with the HQconcentration in the range of20to100μM, with a correlation coefficient of0.9926.