Electrochemical Behaviour Of Gases In Ionic Liquid Sensor

With the rapid development of morden industry,except for the conventional industrial gases such as oxygen and nitrogen,many other gases including hydrogen,carbon dioxide and ozone have been widely used in daily life and industry due to their excellent properties.However,they could also cause severe damage to human beings and environment when they mixed with conventional gases and their gas content beyond a certain concentration range.Thus,the determination of these gases has great research significance.Electrochemical gas sensors has profound application prospect in gas detection because of its small volume,high sensitivity and real-time detection,etc.Ionic liquids could be applied as electrolyte since it has many excellent characteristics such as large electrochemical window,low vapor pressure and low volatility.This thesis focused on the electrochemical behaviour of ionic liquid based electrochemical gas sensor,selected the O₂/H₂,O₂/CO₂ and O₃ system.Several results as following were obtained:?1?Usingcyclicvoltammetryandchronoamperometrytostudythe electrochemical behaviour of different gases including H₂,O₂ and O₃ in[Bmpy][NTf₂]and[Bmim][NTf₂].The result show that compared to[Bmim][NTf₂],gases has better sensitivity and response ability in[Bmpy][NTf₂].[Bmpy][NTf₂]is an excellent electrolyte and could provide the basis for further study.?2?Usingcyclicvoltammetryandchronoamperometrytostudythe electrochemical behaviour and trend as well as performance including sensitivity and stability of O₂/H₂ system in ionic liquid[Bmpy][NTf₂]based-electrochemical gas sensor.The results show that theoxidation potential of H₂ is 0.4V and the reduction potential of O₂ is-1.2V.The current signals of this gas system was found to be in proportion to the gas concentrations and potentials,respectively.Besides,the O₂/H₂ coupling reaction also had great influence on this gas sensor:at positive potentials,the addition of oxygen would decrease the current signal of hydrogen;at negative potentials,the addition of hydrogen would decrease the current signal of oxygen.Moreover,the standard error range is 0.7-0.8,which indicates this gas sensor has good stability.?3?Investigating the electrochemical behaviour and trend as well as performance including sensitivity and stability of O₂/CO₂ system in ionic liquid[Bmpy][NTf₂]based-electrochemical gas sensor.The results show that the reduction potential of CO₂is-2.4V,the current signal of gas system was studied to be in proportion to the oxygen gas concentrations and potentials,respectively.It was found that CO₂ could react with O₂^-whchi result to the increase of the current signals of mixture gas.Besides,this gas sensor has good sensitivity and stability,the standard error is 0.2-0.5nA.