Preparation Of Vertical Graphene Electrode And Its Application In Water Ice Sensor

Graphene is one of the ideal materials for sensor electrodes because of its large specific surface area,high carrier mobility,excellent conductivity,at the same time has a good high temperature resistance,resistance,low temperature characteristics,excellent optical,thermodynamic,mechanical properties and very high mechanical strength.In this paper,a series of vertical graphene electrodes have been developed on Tantalum substrates by using electron assisted hot wire Chemical vapor deposition,ethanol as carbon source and nitrogen atmosphere as assistant.The growth mechanism of vertical graphene shows that the oxygen-containing atmosphere of ethanol decomposition is combined with nitrogen ions produced by plasma glow discharge,this provides a dynamic equilibrium environment for the growth of high purity graphene sheets with a low number of layers of carbon atoms.The optimized vertical graphene electrode has a charge transfer rate constant of more than 0.3 cm s^-1,an effective surface area of 1.8 cm 2,and a very low charge transfer resistance,this provides a rich and stable redox site for collecting the polarization current of biomolecules.Then,using graphene as the working electrode,platinum as the counter electrode,platinum wire as the reference electrode,and a custom made polytetrafluoroethylene cell,the above electrodes are connected to the electrochemical workstation,a three-electrode electrochemical apparatus for water ice detection was developed.The Electron Mobility and temperature stability advantages of graphene at very low temperatures,combined with freeze concentration principles,have led to the first development of a Electrochemical analysis technique for identifying organic ice and inorganic salt ice crystals.The results show that the above-mentioned vertical graphene film-based sensing system qualitatively and quantitatively responds to organic compounds containing carbon and nitrogen such as uric acid,methyl red and methyl orange at room temperature,polarization currents were also collected from the organic water ice,but the polarization current was only about 1/1000th of the liquid state,polarization current of organic compounds and salts in water ice the polarization current of the sensor from organic matter is obviously higher than that of inorganic matter and increases with the increase of its concentration.In addition,the difference of freezing mechanism between Inorganic and organic solutions was explored,and a new method of judging carbon-containing inorganic water ice and organic water ice was proposed based on the difference of impedance stability at-25?.In this paper,an electrochemical strategy was proposed to predict the carbon content in water ice at extremely low temperatures,and inorganic and organic water ice were identified in Situ.The technique can be applied to the exploration of the Earth's extreme environment and even the space resources,including the in-situ detection of organic components in water and ice on the moon and Mars,and the detection of frozen soil resources in the Arctic and Antarctic.