Preparation And Electrochemical Properties Of Indium Oxide Nanosheets Arrays/3d Graphene Composite

Indium oxide?In₂O₃?,a kind of N-type semiconductor functional material,which has a band gap of 3.55-3.75 e V with low resistivity and high catalytic activity has been widely used in photoelectron,gas sensor and catalyst fields.At present,various shapes of In₂O₃ have been developed,such as nanofibers,nanodots,nanotubes,nanosheets,nanofolwers,etc.Compared with nanofibers,nanotubes and so on,nanosheets have larger specific surface area.That means that when it is used as a biosensor electrode,the area that it can contact with the solution is larger,and the active sites that it can provide for biomolecules are also increased.However,the semiconductor band gap determines that its electrochemical performance can not be compared with that of conductor.In order to improve the conductivity of In₂O₃ nanomaterials,three-dimensional graphene?3D Gr?was prepared first by means of chemical vapor deposition?CVD?using foam nickel as template and then In₂O₃ nanosheets arrays were grown on the skeleton of it by hydrothermal synthesis.The In₂O₃ nanosheets arrays/three-dimensional graphene?In₂O₃ NSAs/3D Gr?obtained not only expands the specific surface area,but also improves the conductivity of a single material.The structure and morphologies of In₂O₃ NSAs/3D Gr were characterized by scanning electron microscopy?SEM?,high resolution transmission electron microscopy?HR-TEM?,X-ray diffraction?XRD?,Raman spectroscopy,X-ray photoelectron spectroscopy?XPS?and Brunner-Emmet-Teller?BET?.We can see that graphene has a good three-dimensional porous structure??200?m?and the In₂O₃NSAs grow uniformly on the skeleton of 3D Gr??0.4?m?.According to the analyses of structural characterization,it can be determined that the material is acturally In₂O₃NSAs/3D Gr and the Raman spectra shows that the number of layers of graphene with HR-TEM.The In₂O₃ NSAs/3D Gr was placed on ITO to assemble a three electrode system and dopamine?DA?was detected by electrochemical workstation.The electrochemical analysis of the electrode was carried out mainly by cyclic voltammetry?CV?,differential pulse cyclic voltammetry?DPV?and DPV test with different hydrothermal time and various interferences.The results show that the sensitivity of the electrode is2.69?A·?M^-1·cm^-1 and the detection limit is as low as 0.1?M when concentration of DA is 0-60?M.The sensitivity of DA under UA interference is still 2.47?A·?M^-1·cm^-1 which indicates that In₂O₃ NSAs/3D Gr electrode has good selectivity.In addition,the repeatability,stability and the detection in real samples all meet the ideal standards,which means that this electrode is hopeful to be used in clinical testing.