Synthesis?Characterization And Gas Sensitive Properties Of Tungsten Trioxide Nanomaterials

With the growth of economy,advancement of society,the development of industrialization has been greatly promoted by the arrival of the era of technology and information,mass exhaust gases are unrestrainedlly discharged into the air,acid rainfall,dust-haze,photochemical aerosol,climate warming and other issues emerge in endlessly,environmental pollution has become an urgent issue to be addressed,people gradually award the significance of controlling environmental pollution.For testing toxic,hazardous,flammable and explosive gases in the environment,gas sensor has become the focus of development.In the actual demand,the complicated natural conditions have put forward higher requirements for the properties of gas sensing materials.For the special performances,WO₃ is widely applied in elctrochromic,catalytic and gas sensing fields because of its.Nowadays,tungsten oxide-based gas sensor has become the focus of research and is considered as a potential oxide gas sensing material because of its many advantages,such as simple structure,low cost and excellent gas sensitive properties.The paper aims to improve the gas sensitive performance of tungsten oxide to acetone and H₂S and reduce the fabricating cost.WO₃ is prepared by hydrothermal method,p-n junction is formed by compound CuO to enhance the gas-sensitive performance,and finally a gas sensor is also prepared.The specific work is as follows:Using hydrothermal method,WO₃ with different crystal phase,crystal appearance and size is prepared by controlling different hydrothermal conditions,and the gas sensor based on different morphology materials is also prepared.The results show that the tungsten oxide nanowires as gas-sensing materials of gas sensors of acetone has good gas sensitive performance,and the optimal working temperature is 220?,the sensitivity to 10 ppm acetone gas is about 17.6,the response time and recovery time are 4 s and 15 s,respectively,and the response to 0.9 ppm and 1.8 ppm acetone are significantly different,which provides a favorable condition for the diagnosis of respiratory diabetes.The synthesis method is simple,low cost,and the product has high sensitivity and good stability.The CuO/WO₃ nanocomposite structure with different proportions is synthesized by two hydrothermal methods and processed into gas-sensitive elements.The hydrogen sulfide gas is detected and its principle is analyzed,the result indicates that the CuO/WO₃ composite with W:Cu of 100:5 shows the best gas sensitive properties.The sensitivity to H₂S at 10 ppm at 180?is about 318.4,the response time is about 40 s,and the recovery time is about 30 s.Besides,it has good moisture resistance and good selectivity,is not sensitive to gases such as acetone,methanol,ethanol and ammonia.