Preparation Of Modified Conductive Polyimide Electrodes And Application In Sensor And Catalysis

The electrochemical sensors based on the new modified electrode have important scientific significance and practical value for the analysis of food, medicine, environmental pollutants and a variety of materials. In this master’s paper, we prepared successfully carbon nanotube/polyimide（CNT/PI） and the graphene/polyimide（Gr/PI） composite film electrodes, and then prepared nano-functional materials with sensing catalytic properties on the surface of thin film by the current-time method（i-t）, cyclic voltammetry（CV） and other technologies to produce the corresponding modified electrode. The structure, morphology and composition of the modified electrodes were analysed by means of scanning electron microscopy（SEM）, X-ray diffraction（XRD）, transmission electron microscopy（TEM）, X-ray photoelectron spectroscopy（XPS） and Fourier transform infrared spectroscopy（FT-IR） and so on. The as-prepared modified electrodes were used to build electrochemical sensor for the analysis of real samples and catalytic performance research. Mainly includes the following three aspects: 1. The electrodeposition preparation of the Ni（OH）₂/MoS_x nanocomposite on the CNT/ PI film electrode and its study of the glucose sensor performanceThe molybdenum sulfide-nickel（II） hydroxide（Ni（OH）₂-MoS_x） nanocomposite was prepared in sequence on flexible CNTs/PI film electrode by a two-step electrochemical deposition method. The as-prepared Ni（OH）₂/MoS_x/CNT/PI modified electrode was used in the construction of glucose sensing methodology. The structure properties and the research for glucose sensing behavior of this modified electrode were characterized by SEM, XRD, XPS, CV and chronoamperometry. Experimental results showed that the constructed glucose sensor’s linear response range is 10¹600 μmol L-1 and the detection limit is 5.4μmol L-1（S / N = 3）. Also the glucose sensor has some features, such as a fast response time（about 3s）, good stability, strong anti-interference ability and so on. It was found that the synergistic effect between Ni（OH）₂ and MoS_x is a key factor for glucose sensor successfully constructed. Furthermore, the sensor was successfully applied to detect glucose in human blood serum samples 2. The modification of melamine on CNT/PI film electrode and its sensing reserach for Sudan IThe poly melamine（P-（melamine）） was prepared on the CNT / PI film electrode by electro-polymerization method. The constructed P-（melamine）/CNT/PI modified electrode was used to study the electrochemical sensor for food additive Sudan I. The structure, morphology and the electrode chemical behavior for Sudan I of this modified electrode were characterized by Fourier transform infrared spectroscopy（FT-IR）, SEM, CV and linear sweep voltammetry（LSV）. The results show that the modified electrode has a good oxidation peak current response at ⁰.68 V（vs.SCE） for Sudan I. The experimental results show that the constructed Sudan I sensor has a linear response range of 0.01 12 μmol L-1（the correlation coefficient of 0.997） and it’s detection limit is 1.8 nmol L-1（S / N = 3）. Also it has good stability, repeatability and selectivity. Furthermore, this sensor was successfully applied to detect Sudan I in practical samples. 3. The preparation of Pd-micro-NPs/COOH-CNTs/PI and Pd-micro-NPs/Gr/PI catalytic film electrode and its study on catalyzing formic acidThe flexible COOH-CNTs/PI and Gr/PI catalytic film electrode material were prepared with COOH-CNTs, Gr and PI. Then, we prepared flower-shaped micro-Pd nanoparticles（Pd-micro-NPs） catalyst on the surface of corresponding catalytic film electrode material by i-t deposition method. The as-prepared catalytic film electrode materials were characterized by XRD, SEM, CA and CV etc. It was found that Pd-micro-NPs/Gr/PI catalytic material has higher catalytic efficiency for formic acid and better stability, when compared with the Pd-micro-NPs/COOH-CNTs/PI. This is because the Pd-micro-NPs/Gr/PI film has the smaller particle size, higher density and more uniform distribution.