Research And Design Of NO₂ Gas Detection

In the 21 st century, with high speed development of science, technology and economy, environmental pollution has become a widespread concern. Atmospheric environmental pollutants mainly come from all kinds of chemical reactions in the process of industrial and agricultural. And NO₂ is one of the major pollutants of air pollution; it is a major factor in the formation of photochemical smog and acid rain. It is also one of the national environmental monitoring projects. NO₂ is highly hazardous to people. And it may damage to your lung even you exposure to NO₂ just for a short time. So it has a special significance of monitoring of NO₂ in environmental protection, pollution control.In this dissertation, a study is performed about NO₂ system analysis and design, which mainly analyses the adsorption properties of graphene for NO₂. The experiment of adsorption properties of graphene for NO₂ is based on the special two-dimensional material graphene. Because of its special structure, graphene has the great advantages of gas sensor. This paper calculates adsorption properties of graphene for NO₂ by soft simulation firstly. Then design a NO₂ gas sensor based on graphene to carry out the experiment. The experimental data are in reasonable agreement with simulation result. The response and recovery time are main parameters for gas sensor. The graphene-based sensor could recover to their initial states, but the recovering time is longer, which is impeding the sensor applications in time. The experiment shows that the sensor’s response time is fast and the recovery time is slow. Some literatures have proposed method that a UV light shining is useful to expedite desorption of NO₂ molecules and improve the recovery time of the sensor based on graphene. In order to test and verify this method, we carried out this experiment and observed this phenomena. The study also found that a white light and blue light is also useful. So we speculate that this is because of the NO₂ have its specific absorption line patterns. Finally we design a system to analyze the absorption spectrum of NO₂.As a new material which has many excellent performance, graphene still has great potential in many aspects. This paper analyses the adsorption properties of graphene for NO₂ is in order to explore the new method for the detection of NO₂. Otherwise, is also hope it can make further development of graphene in gas sensing.