Fabrication Of Micron Or Submicron Structures On Electrode Surface And Their Electrochemical Properties

In this paper, different types of modified electrodes are built on the surface of an indium tin oxide(ITO) electrode. And as-prepared modified electrodes are used to construct electrochemical sensors which are responsible for further electrochemical research.The main research results are as follows:1. A facile fabrication approach for polyaniline(PANI) incorporated with gold nanoparticles(Au NPs) composite electrode by electrodeposition of PANI on self-assembled Au NPs layer on the surface of ITO electrode is reported. The resulting Au NP/PANI composite electrode exhibitsaremarkable synergistic effect on the electrocatalytic oxidation of ascorbic acid(AA) and dopamine(DA).It is demonstrated that the oxidation reaction of AA mainly occur at Au NPs inside PANI film as the ascorbate anions are doped into the polymer during the oxidation of PANI film. On the other hand, the oxidation of positively charged DA can only take place at PANI/solution interface. The different mechanisms of the electrode reactions result in the oxidations of AA and DA occurring at different potentials. As a result, the Au NP/PANI composite electrode can be employed to simultaneously detect AA and DA with good linear range, high sensitivity and low detection limit.2. A highly ordered self-assembled monolayer of polystyrene(PS) microspheres is used as a template to electrochemically polymerization of PANI in the Si O2 cavities, which is fabricated on the surface of an ITO electrode. Moreover, it is found that the edge effect of the array microelectrode plays a significant role in controlling the two dimensional(2D) growth of PANI. Notably, the bowl-like PANI-cavity modified electrode exhibits higher electrocatalytic activity towards the oxidation of AA than the planar PANI/ITO electrode. The electrode shows a linear response with the concentration of AA in the range from 0.5 μM to 0.33 m M, and a low detection limit of 0.31 μM(S/N = 3).3. When using a highly ordered Si O2 array as working electrode, platinum nanoparticles can be electrochemically deposit under the bottom of the cavities owing to the poor conductivity of Si O2 cavities structure. A novel biosensor is fabricated by further connecting between glucose oxidase(Gox) and inner cavities wall via covalent bonds. The as-fabricated biosensor can be used for the detection of glucose. Based on the electrochemical behaviors of the Gox/Pt-Si O2 modified electrode, Gox are successfully immobilized the inner cavities and can still remain active during the detection process. Experimental results indicate that the Gox/Pt-Si O2 modified electrode exhibits good electrocatalytic performance on the oxidation of glucose. The preparation of biosensor is simple, fast and enzyme even does not require the activation.