Controllable Preparation Of Nanomaterials With Different Dimensions And Their High Performance In Electrochemical Biosensor

Graphene and conductive polymer nanomaterials have been widely used in the field of sensoring, energy storage and electronic devices, due to their excellent properties, such as high conductivity, large specific area, low-cost preparation, and good biocompatibility. The syntheses of one-dimensional PANI nanotubes and PANI/Au composite nanotubes, two-dimensional Mn O2/graphene nanocomposites and network structural three-dimensional nitrogen-doped graphene have been achieved by template method, hydrothermal method, and chemical vapor disposition(CVD). The structure, morphology, and composition of the resulting products were characterized by transmission electron microscopy(TEM), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD), thermogravimetric analysis(TGA), Fourier transform infrared spectroscopy(FT-IR), Ultraviolet visible(UV-vis) absorption spectrum and Raman spectrum. The applications in electrochemical biosensor of the as-prepared nanomaterials have been studied as well. The main contents could be summarized as follows:1. One-dimensional polyaniline(PANI) nanotubes with improved electrochemical activity were synthesized by using a self-degradable Mn O2 template and were developed as electrode materials for biosensors. The results confirmed that the obtained PANI nanotubes had a perfect tubular structure with uniform diameters and lengths. The obtained PANI-modified GCE showed high catalytic activity in the electrochemical oxidation of dopamine(DA) in a near neutral environment. Differential pulse voltammogram(DPV) results illustrated that the fabricated DA biosensor had high anti-interference ability towards uric acid(UA), ascorbic acid(AA), and glucose(GC). In addition, the fabricated biosensor showed superior performance with two wide linear ranges from 7×10-5 to 3×10-4 M and 3×10-4 to 5×10-3 M with a lower limit of detection of 0.5×10-9 M.2. One-dimensional polyaniline(PANI) /Au composite nanotubes were synthesized and developed as an electrode material for the detection of NADH(nicotinamide adenine dinucleotide). Cyclic voltammogram(CV) experiments indicated that PANI/Au-modified GCE showed a higher electrocatalytic activity towards the oxidation of NADH compared with that of PANI-modified GCE in a neutral environment. Differential pulse voltammogram(DPV) results illustrated that the fabricated NADH sensor had excellent anti-interference ability and displayed a wide linear range from 4×10-4 to 8×10-3 M with a detection limit of 0.5×10-7 M.3. Two-dimensional Mn O2/graphene nanocomposites with different morphologies were synthesized and the petal-shaped nanosheet Mn O2/graphene composite was developed as an electrode material for nonenzymatic hydrogen peroxide(H2O2) sensor. Cyclic voltammogram(CV) experiments indicated that Mn O2/graphene-modified electrode showed good electrocatalytic activity towards both the oxidation and reduction of H2O2 in a neutral environment. Amperometric response results illustrated that this nonenzymatic sensor had excellent anti-interference ability and displayed two linear ranges from 10 to 90 mM and from 0.2 to 0.9 m M with a detection limit of 2 mM.4. Three-dimensional nitrogen-doped graphene(3D N-doped graphene) was prepared through the chemical vapor deposition(CVD) by using porous nickel foam as a substrate. As a model, a dopamine biosensor was constructed based on the 3D N-doped graphene porous foam. Electrochemical experiments exhibited that this biosensor had remarkable detective ability with a wide linear detection range from 3×10-6 M to 1×10-4 M and a low detection limit of 1 n M. Moreover, the fabricated biosensor also showed excellent anti-interference ability, reproducibility, and stability.