| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 99 === This study is comprised of two parts: (I) the synthesis of novel Pt-Pd/ multi-wall carbon nanotubes (MWCNTs) catalysts for the applications of electrochemical sensing of hydrogen peroxide. (II) Immobilization of glucose oxidase by electrochemi
cal deposition of chitosan.
(I) Oxidation of Multi-wall carbon nanotube was attempted by various acids, such as sulfuric acid, nitric acid.The oxidation who achieved effectively by mixing sulfuric acid and nitric acid in 1:1 ratios. The syntheses of (PtxPd1-x/MWCNTs) catalysts were carried out at different atomic ratios of metal precursor by modified Watanabe colloidal synthesis method in liquid phase at pH 6. The Pt3Pd1/MWCNTs catalyst was found to show the best performance toward hydrogen peroxide quantification. TEM analyses showed the particle size of the catalysts was approximately same (2-5 nm). From this observation, it was found that particle size and hydrogen peroxide oxidation reaction are independent at the same metal loading on the carbon nanotube.
(II) The optimum structure of the sensing layers who developed. The additions of cross-linking agent enhanced the cross-linking reaction between enzyme and chitosan. The solution recipe and parameters for the electrochemical deposition were optimized. The enzyme kinetics (Michaelics-Menten constant = 5.3 mM) and stability tests have been demonstrated that the sensitivity decay of the assembled electrodes is around 10 % after 7 days. It shows that the assembled sensor prepared under this condition provide mild environment for enzyme immobilization and 3D network membrane facilitate the bio-reaction between enzyme and bio-species, which makes enzyme exhibiting good affinity and stability.
The prepared glucose sensor exhibits a sensitivity of 104 μA/mMcm2 in detection range between 0.031 mM and 14.07 mM (R2 =0.990) at 0.6 V (vs. SCE). The optimum mini-strip shows 344.57 μA/mM cm2 in detection range up to 10 mM (R2 =0.99, N=3). The results the glucose strips with a high sensitivity, reproducibility and stability are fabricated via the combination of synthesized bimetallic nanocatalyst and electrochemical deposition.
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