Fabrication Of 3D Nirtrogen Doped Graphene Functional Nanocomposites And Their Electrochemical Properties And Applications

In this thesis,the prepared 3D nitrogen doped graphene herogel?3DNGH?not only maintain the excellent property of graphene,but also had an exceptionally large accessible surface area even tightly packed.Particularly,nitrogen doping was an effective method to intrinsically improve the conductivity of 3DNGH.Based on the outstanding electrochemical property,the application of the 3DNGH nanocomposites was in the field of the electric catalysis activity of methanol oxidation,PEC sensors and the application of biological sensors.The details research content were focused on:1.A simple hydrothermal method was developed for the successful preparation of platinum nanoparticles?PtNPs?decorated 3DNGH.Pt NPs with a size about 2-3 nm were well-dispersed and tightly anchored on the3 D porous graphene sheet.Compared to PtNPs-decorated 3D graphene hydrogel?PtNPs/3DGH?and PtNPs-decorated 2D graphene?PtNPs/2DG?composites,PtNPs/3DNGH electrode demonstrates excellent electrocatalytic activity for the oxidation of methanol,which could enhance the peak current density by 1.6 times and 2.2 times,respectively.And the electrochemical active surface area of PtNPs/3DNGH is 42.17m2/g while those of PtNPs/3DGH and PtNPs/2DG composites are 19.38m2/g and 12.05 m2/g.Therefore,the catalyst with a good catalytic property has a potential application value in the high-performance fuelcell.2.The ZnO/3DNGH nanocomposites were prepared through a one-pot hydrothermal method.Compared to ZnO decorated 3D graphene hydrogel and ZnO decorated 2D graphene,the PtNPs/3DNGH enhanced photocurrent intensity by 1.5 times and 2.1 times,respectively.Futhermore,using the prepared ZnO/3DNGH nanocomposites as HRP immobilization supporter,On the basic of biocatalytic precipitation reaction and steric hindrance,established photoelectrochemical biosensor for the determination of H₂O₂.The resulting PEC sensor exhibited a wide linear range from 0.001 to 5 mM with a low detection limit of 0.33 ?M?S/N = 3?.And the resulting platform was also extended for glucose detection by further immobilizing glucose oxidase.Meanwhile,the proposed PEC sensor displayed a linear response for glucose in the range from 0.002 to 8 mM,with an extremely low detection limit of 0.66 ?M?S/N = 3?.The sensor exhibited good stability and reproducibility,which had potential application prospect and value in the detection of orange juice.3.The AgBr/3DNGH nanocomposites were firstly obtained by hydrothermal method.Further,using the prepared luminol/AgBr/3DNGH?luminol/AgBr/3DNGH?nanocomposites as aptamer immobilization supporter and the as-prepared luminol/AgBr/3DNGH nanocomposite could react with the coreactant H₂O₂ to generate strong and stableelectrochemiluminescent?ECL?.The AgBr/3DNGH showed nearly2-fold,3-fold and 8-fold enhancement ECL intensity compared to AgBr/3DGH,3DNGH and AgBr/2D nitrogen-doped graphene,which developed a novel electrochemiluminescence spectroscopy for detection of E.Coil.Under the optimal condition,a good linear relationship was obtained between the ECL intensity and the E.coil concentration over the range from 0.5 to 500 cfu/mL with a detection limit of 0.17 cfu/mL?S/N=3?.The developed sensor,which could be applied for the detection of milk samples.