Glucose And Hydrogen Peroxide Electrochemical Sensing Research Based On Nanocomposites

Because of various limitations of electrochemical sensors in practical application, nanocomposite materials have attracted more and more attentions due to the simple fabrication, good stability and high sensitivity. In this paper, eight kinds of electrochemical sensors were fabricated based on metal, metal oxides, graphene, carbon nanotubes and halloysite, etc. The performance of new materials and the relationship between the structure and morphology, the electrochemical and electrocatalytic behavior of sensors were investigated and the new electroanalytical method for determination of glucose and hydrogen peroxide were stablished. This study enriches the research contents of electrochemical sensing, and broadens the application range of nanomaterials. The thesis is divided into four chapters. The author's main contributions are summarized as follows:1. Two kinds of non-enzymatic electrochemical glucose sensors were fabricated based on porous Ni/MnO2 and Cu/TiO2-SnO2 nanocomposite which were synthesized by electrodeposition and chemical synthetic methods respectively. We investigeted the electrochemical and electrocatalytic behavior and performed new electroanalytical methods for detection of glucose. The experimental results indicated that the Ni/MnO2 modified sensor exhibited good properties with a catalytic oxidation potential of 0.45 V, a linear range: 2.5×10-7?3.5×10-3 mol·L-1, a sensitivity:1042 ?Am·M-1·cm-2 and a detection limit:1.0×10-7 mol·L-1 (S/N=3). The Cu/TiO2-SnO2 modified sensor exhibited good properties with a catalytic oxidation potential of 0.60 V. The linear range for the determination of glucose was 2.0×10-6?1.8×10-2 mol·L-1, the sensitivity was 256.3 ?A-mM-1·cm-2 and the detection limit was 7.0×10-7 mol·L-1 (S/N=3). Fabrication of electrochemical sensors based on the two porous nanomaterials are simple, and it can be seen clearly that the linear range of Cu/TiO2-SnO2 modified sensor is an order of magnitude broader than that of Ni/MnO2 while the sensitivity is four times higher.2. The carbon nanomaterials were used as substrates, then four kinds of electrochemical sensors were fabricated based on Cu/Mn2/MWCNTs, Cu/NiO/MWCNTs Cu/MnO2/G-IL and Ag2S/MWCNTs nanocomposites which were synthesized through chemical synthetic methods. The electrochemical and electrocatalytic behavior were investigated. The new electroanalytical methods for detection of glucose and hydrogen peroxide were performed. The experimental results indicated that Cu/MnO2/MWCNTs modified sensor exhibited a linear range:6.4×10-7?2.0×10-3 mol·L-1, a detection limit: 1.7×10-7 mol·L-1 (S/N= 3) and a sensitivity:1302 ?A·mM-1·cm-2. Cu/NiO/MWCNTs modified sensor exhibited good properties with a catalytic oxidation potential of 0.60 V, a linear range:4.5×10-7·2.0×10-3 mol·L-1, a sensitivity of 637.2 ?A·mM-1·cm-2 and a detection limit of 1.5×10-7 mol·L-1 (S/N= 3). The catalytic oxidation potential was 0.50 V, the linear range for the determination was 3.0×10-7?1.8×10-3 mol·L-1, the sensitivity was 782.6 ?A·mM-1·cm-2 and the detection limit was 1.0 ×10-7 mol·L-1 (S/N= 3). In addition, Ag2S/MWCNTs modified sensor also exhibited good properties. The catalytic oxidation potential was -0.35 V, the linear range for the determination of H2O2 was found to be 8.0×10-7·2.4×10-3mol·L-1 and the detection limit was 4.0×10-7mol·L-1 (S/N= 3).Fabrication of electrochemical sensors based on the four kinds of carbon nanomaterials are simple, and the linear ranges are all broad. In three of glucose sensing materials, Cu/MnO2/MWCNTs modified sensor exhibited highest sensitivity.3. HNTs were used as substrates, two kinds of non-enzymatic electrochemical sensors were fabricated by layer-by-layer assembly. Pt/GE/HNTs and Ni(OH)2/HNTs-BMIMPF6 nanocomposite were used in these sensors. We investigated the electrochemical and electrocatalytic behavior and performed new electroanalytical methods for detection of glucose. The experimental results indicated that Pt/GE/HNTs modified sensor exhibited good properties with a catalytic oxidation potential of 0.35 V, a detection limit of 1.0×10-7 mol·L-1 (S/N= 3) and the linear range of 3.0×10-7?5.7×10-3 mol·L-1. The Ni(OH)2/HNTs-BMIMPF6 modified sensor exhibited good properties with a catalytic oxidation potential of 0.50 V. For determinating glucose, the detection limit was 1.7×10-6 mol·L-1 (S/N= 3) and the linear range was found to be 5.0×10?5.6×10-3 mol·L-1. Compared with Ni(OH)2/HNTs-BMIMPF6, Pt/GE/HNTs modified sensor exhibited the broader linear range and lower detection limit.