Research On Detection Technology Of Hydrogen Sulfide Based On Semiconductor Polymer

H₂S gas is naturally produced as a result of the breakdown of organic materials.H2 S gas is colorless,corrosive,flammable,extremely toxic and potentially lethal in low concentrations,as low as few parts per million.In addition,H2 S gas is flammable and explosive,which is easily mixed with oxygen in the air and is liable to cause catastrophic disaster.Therefore,the inevitable risks of H2 S gas and the demand for higher performance with lower power-consumption sensors urge the search of new materials that are capable of fulfilling these demands.This work aims to study gas sensing performance of the H2 S sensor based on chitosan composite material.The sensors designed in this work are electrical resistance types which are composed of stainless steel grid top electrode,bottom electrode and sensing films.The sensing films we studied are chitosan film,nanowire chitosan film and chitosan/graphene oxide composite film,respectively.The differences between the gas sensing properties of the three sensors were tested on a self-assembled gas sensing test platform,and the results were analyzed.Firstly,we study the sensing performance of chitosan film for H2 S gas detection at different temperture.The results revealed that the sensitivity of the sensor increases with operating temperture within a certain range,but the sensor could detect effectively H2 S gas at room temperture.The liner response and selectivity of the sensor to H2 S gas are excellent.The sensor shows a high resolution for H2 S gas.Secondly,the nanowire chitosan film was prepared which using silicon wafer with a period of 1.5um as mask through self-assembled two-beam interference system.The gas sensing performance was investigated.The results show that the response time and sensitivity of the nanowire sensor are improved due to larger specific surface area of the chitosan film and more functional groups exposed,which provides more adsorption sites for H2 S molecules,thus enhancing the corresponding gas sensitivity of the chitosan film.Finally,the chitosan/graphene oxide composite film was fabricated by solution blending method.The optimal ratio of graphene oxide to chitosan was found and the sensing properties of the sensor were investigated.The results show that the incorporation of GO has a positive impact on the sensitivity and stability of the sensor.It is speculated that a large number of functional groups on the surface of the GO promote hydrogen bond generation and cross-link with chitosan molecules to form a more complex spatial network structure,which enhances the mechanical properties of the material and positively locks the moisture inside the film.