Fabrications And Applications Of Electrochemical Sensors Based On Single-Walled Carbon Nanohorns

Carbon nano-materials are widely used as electrode modifier due to their large surface area, thermal and chemical stability, good conductive ability and excellent electro-catalytic ability. As a novel carbon nano-material, single-walled carbon nanohorns (SWCNHs) receive much attention because of their without using metal catalyst, high purity and tractable property. In this dissertation, we studied on the developments and applications of the novel electrochemical sensors based on SWCNHs. The main points of this thesis are summarized as follows:1. A new hydrazine sensor has been fabricated by depositing gold nanoparticles (Au) at the surface of a GCE modified with SWCNHs, forming an Au/SWCNHs composite matrix on glassy carbon electrode (Au/SWCNH/GCE). The results showed that the sensitivity of Au/SWCNHs/GCE for determination of hydrazine had a prominent improvement compared with the glassy carbon electrode only modified with gold nanoparticles (Au/GCE). The performances of the Au/SWCNHs/GCE were characterized with cyclic voltammetry (CV) and amperometric determination (i-t). The amperometric detection of hydrazine was carried out at0.3V in0.1mol/L phosphate buffer solution (pH7.4) with two wide linear ranges from5to645μmol/L and from645to3345μmol/L. The detection limit of hydrazine was1.1μmol/L (s/n=3).2. The modified electrodes was fabricated by dropping SWCNHs solution onto the surface of the GCE and used for β-niacinamide adenine dinucleotide (NADH) detection. The electrochemical properties of the sensor and its electrocatalytic oxidation behaviors towards NADH were studied by CV. The overpotential reduced and the peak current increased significantly. The linear range for the detection of NADH was from1×10-5to1.1×10-3mol/L with a detection limit of3x10-7mol/L (s/n=3).3. In this paper, a novel ethanol sensor has been fabricated by depositing palladium nanoparticles (Pd) at the surface of a GCE modified with SWCNHs. The electrochemical property of the modified electrode was studied by CV and exhibited excellent electrocatalytic activities toward the oxidation of ethanol. The linear range and detection limit for ethanol were evaluated by Linear Sweep Voltammetry (LSV) in0.1mol/L NaOH. The oxidation peak current was in linear relationship with ethanol concentration in the range from3.4×10-3mol/L to1.19×10-1mol/L with a detection limit of4.7×10-4mol/L (s/n=3).