The Study Of Nonenzymatic Hydrogen Peroxide Sensors Based On Carbon Nanotube And Metal Nanoparticles

Metal nanoparticles have been widely used in the construction of the sensor due to theirrelatively large specific surface area, high surface energy and high catalytic activity.Meanwhile, carbon nanotubes possess excellent electric conductivity，high chemical stabilityand high catalytic activity. Moreover, carbon nanotubes have been used as effective loadmatrix for the deposition of nanoparticles. Therefore, the synergistic effect of carbonnanotubes and metal nanoparticles could make the chance for improvement the properties ofbiosensors and promote the development of biosensors effectively.This dissertation focusedon the study of the nonenzyme hydrogen peroxide sensor based on carbon nanotubes andnanoparticles.The main contents were summarized as follows:1. Ionic liquid functionalized multiwalled carbon nanotube (MWCNTs-IL) was firstprepared by amidation between carboxylic acid functionalized MWCNTs (MWCNTs-COOH)and the amine-terminated IL (IL-NH2). Then a novel hydrogen peroxide (H2O2) sensor wasfabricated by electrodepositing Ag nanoparticles (NPs) on a glassy carbon electrode (GCE)modified with MWCNTs-IL composites. The large amounts of small-sized AgNPs could bewell deposited on the surface of the MWCNTs-IL modified electrode, as revealed by scanningelectron microscopy (SEM). The constructed electrode exhibited good catalytic activitytoward the reduction of H2O2, and obtained a linear response to logarithm of the H2O2concentrations ranging from1.2×10-8to4.8×10-6mol·L-1with a limit of detection (LOD)of3.9×10-9mol·L-1. Moreover, the catalytic mechanism of the constructed sensor wasproposed. AgNPs dispersed on MWCNTs-IL were used as the catalyst for the H2O2into O2,and the generated oxygen transported the electrode surrounding where it was detected byreduction on the electrode.2. From the first chapter, we found that the structure of CNTs could be destroyed easily bythe covalent effect, although the covalent functionalization of CNTs has good dispersibilityand stability. In this chapter, MWCNTs was first non-covalent functionalized with ananionic surfactant, sodium dodecyl sulfate (SDS), which could decrease the surface energy ofMWCNTs; then the Pt nanoparticles (NPs) were loaded on MWCNTs-SDS byelectrodepositing. The experimental results demonstrated that the constructed electrode exhibited excellent catalytic activity toward the hydrogen peroxide, and a wide linear rangefrom5.8×10-9to1.1×10-3mol·L-1was obtained with a limit of detection (LOD) of1.9×10-9mol·L-1, which was superior to that obtained with other H2O2electrochemical sensorsreported previously. Moreover, it can also be applied to real samples analysis. The excellentperformance of hydrogen peroxide sensor was attributed to the MWCNTs-SDS compositesbeing used as effective load matrix for the deposition of PtNPs and the synergisticamplification effect of the two kinds of nanomaterials—PtNPs and MWCNTs.3. Gold-platinum nanoparticles (Au-PtNPs) have a large specific surface area, goodbiocompatibility, and excellent electrical conductivity. A novel hydrogen peroxide (H2O2)sensor was fabricated by electrodepositing Au-Pt nanoparticles (NPs) on a glassy carbonelectrode (GCE) modified with ionic liquid functionalized multiwalled carbon nanotube(MWCNTs-IL) composites. The Au–PtNPs/MWCNTs-IL composite was characterized bydifferent methods including cyclic voltammetry (CV) and electrochemical impedancespectroscopy (EIS). The constructed electrode exhibited good catalytic activity toward H2O2,and a wide linear range (1.0×10-9～1.2×10-7mol·L-1) was obtained with a low limit ofdetection（4×10-10mol·L-1）.