Study On The Electrocatalytic Properties Of Nanostructured Materials For Analysis

In-situ Fourier transform infrared (FTIR) reflection spectroscopy is one of the most powerful techniques which gives molecular specific information as to adsorbed species at electrode-solution interfaces during electrochemical process. Some research work are shown in this thesis carried out with the home-made in-situ FTIR reflection system.1. Mechanism investigation of Prussian blue electrochemically deposited from a solution containing single component of ferricyanidePrussian white (a reduced state of Prussian blue) was electrochemically deposited on a polycrystalline Pt electrode from an acidic solution of ferricyanide. Electrochemical measurements showed that the formation of Prussian white on platinum electrode was a self-terminating process. A compacted PB film can be formed by using both potential scanning and potentiostatic methods as confirmed by AFM measurement. In-situ FTIR measurements were carried out to explore the formation mechanism. The new band arising at2075cm-1is assigned to the stretching vibration mode of CN bond in Prussian white, while the band at2104cm"-1is due to the absorbance of CN bond in Prussian blue. A possible mechanism of electrodeposition of Prussian white was discussed.2. Effects of the roughness of porous Pt electrodes on the elecetrochemical oxidation of ethanol The electrochemical oxidation of ethanol on porous Pt and smooth polycrystalline Pt electrode is studied using cyclic voltammetry and in-situ Fourier transform infrared spectroscopy (FTIR). CO2, acetaldehyde and acetic acid have been detected. From in-situ infrared spectroscopy, it is found that porous Pt electrode is much more active for the electrochemical oxidation of ethanol, because the ratio of the band integral intensity of CO2to that of CH3COOH increases significantly with Pt layer on the Pt electrode. Combined with the investigations of XRD, SEM and AFM on the surfaces of these electrodes, the possible reasons for the different reactivity of the studiedporous Pt are discussed.3. Highly dispersed Pt nanoparticles supported on carbon nanotubes for selectively nonenzymatic detection of glucoseHighly dispersed platinum nanoparticles supported on multi-wall carbon nanotubes (MWCNTs) were synthesized using an easy two-step approach including adsorption and pyrolysis. The resulting catalysts show good electrocatalytic activity toward the oxidation of glucose in alkaline and thus were applied to selective detection of glucose. Detection potential and the amount of Nafion covered on the Pt-MWCNT modified glassy carbon electrode was found to have considerable influence on the selectivity for amperometric detection of glucose. Under the optimal detection conditions (detection potential of0.0V vs SCE and10uL1.5%Nafion), selective detection of glucose in the glucose concentration ranging from1.0mM to26.5mM (correlation coefficient,>0.999) can be performed. The results demonstrate that the Pt-MWCNT composite is promising for the fabrication of nonenzymatic glucose sensors.4. Construction of the electrochemical sensors based on Prussian blue and inverted colloidal crystal templates respectively By utilizing the macroporous palladium films electrodes fabricated from Prussian blue and inverted colloidal crystal templates respectively, the novel functional interfaces were developed for the fabrication of nonenzymatic glucose sensors and biosensors. Under the optimal conditions, selective detection of glucose in the glucose concentration ranging from1.0mM to60mM (correlation coefficient,>0.999) can be performed. These electrodes also have good anti-interfere ability toward UA, AP and AA. The present results show that they can be used for the construction of nonenzymatic glucose sensor.