Study On Enzyme-free Electrochemical Sensor Based On Nickel Composites

Nickel and nickel oxide have stable chemical properties,excellent biocompatibility and good electrocatalytic performance,is widely used in enzyme-free electrocheical sensors.However,there is a certain defect in nickel and its oxides,which leads to some restrictions on the application of enzyme-free electrochemical sensors.In this paper,nickel-based composites were prepared by doping nickel and its oxides with other materials to improve the electrocatalytic activity of Ni-based composites and construct novel enzyme-free sensors.The main contents of this thesis are follows:?1?Preparation of carbon-nitrogen doped nickel oxide microspheres?Ni O?novel composites?C-N/Ni O?and fabricate hydrogen peroxide?H₂O₂?enzyme-free electrochemical sensors.Ni O was prepared by solvothermal method,and C-N/Ni O composites were obtained by calcining the mixture of Ni O and diblock copolymer poly?2-hydroxyethyl methacrylate?-b-poly?2-?dimethylamino?ethyl methacrylate?(PHEMA₂₀₀-b-PDMAEMA₁₀₀)at high temperature.The morphology and electrocatalytic performance of the samples as prepared were characterized by scanning electron microscopy?SEM?,X-ray diffraction?XRD?,cyclic voltammetry?CV?and amperometrc current-time curve?i-t?.The result shows that the C-N/Ni O modified glass carbon electrodes?GCE??denoted as C-N/Ni O/GCE?exhibits excellent electrocatalytic performance for hydrogen peroxide?H₂O₂?determination:alower detection limit with 0.042?M?S/N=3?.Therefore,the Ni O@C/N/GCE has potential to be excellent for fast determination of hydrogen peroxide,which is applied to medicine management,environmental protection and food safety.?2?Preparation of Ag coated Ni O hollow spheres composites?Ag/Ni O HS?and fabricate glucose enzyme-free electrochemical sensors.Ni O HS was synthesized by hydrothermal method,and then Ag/Ni O HS was fabricate by seed-induced growth procedure.The morphology and electrocatalytic performance of the samples as prepared were characterized by SEM,XRD,and CV.The result shows that the 2%Ag/Ni O HS modified GCE?denoted as 2%Ag/Ni O HS/GCE?exhibits excellent electrocatalytic performance for glucose determination:a much higher sensitivity withrange under the synergistic effect was achieved between Ag and Overall,these results indicate that the Ag Ni O HS based sensor is a promising candidate in the development of highly sensitive and selective nonenzymatic glucose sensors.?3?Preparation of nickel doped graphitic carbon nitride?Ni/g-C₃N₄?composites and fabricate bisphenol A?BPA?enzyme-free electrochemical sensors.Ni/g-C₃N₄ was prepared by thermal treatment the mixture of melamine and Ni Cl₂·6H₂O.The morphology and electrocatalytic performance of the samples as prepared were characterized by SEM,XRD,infrared?IR?,alternating-current impedance?EIS?and differential pulse voltammetry?DPV?.The result shows that the 10%Ni/g-C₃N₄modified GCE?denoted as 10%Ni/g-C₃N₄/GCE?exhibits excellent electrocatalytic performance for BPA determination:the linear range are 0.01 n M to 1?M and 1?M to 100?M,with a limited detection of 4.34 n M?3S/N?.Therefore,Ni/g-C₃N₄composites based sensor has great potential value in BPA detection.