The Gas Sensing Properties Of Semiconductor Metal Oxides On Volatile Organic Compounds Gases

Today's social development is changing with each passing day,and the environment we rely on to survive is becoming more and more complex.Volatile organic compounds gases?formaldehyde,benzene and benzene compounds,methanol,acetone,etc.?can be encountered everywhere in our lives,always harming human health.Once the disease is triggered,it will be an irreversible situation.Gas sensors are responsible for detecting and monitoring the ambient air.The semiconductor metal oxide gas sensors are convenient,portable,economical,and have outstanding response performance.They have attracted the attention of researchers.However,semiconductor metal oxide gas sensors have always the problems of poor selectivity,high operating temperature,and high detection limits.Although the metal oxides modified by precious metals can improve the response value and speed to a certain extent,it does not improve the selectivity problem.In addition,precious metal is poor storage and expensive,which greatly limits its research and application value.Therefore,our research goal is to achieve low working temperature,selective detection of indoor volatile organic compounds gases by using semiconductor metal oxide gas sensors.1.WO_x clusters-modified indium oxide ultrathin nanosheets obtained by a simple solvothermal-impregnation-calcination method,and were used as sensitive materials for the detection of formaldehyde gas.The response value of 4 wt%WO_x/In₂O₃ composite sensor is about twice as high as that of the pure In₂O₃ sensor.In addition,the WO_x-In₂O₃ sensors were operated at a lower working temperature?170??,detection limit can reach 100 ppb,with good selectivity and long-term stability.It achieves the targets of non-precious metal modification,low operation temperature,and selective detection.2.MoO₃ nanobelts obtained by the hydrothermal method and used for the detection of xylene after heat treatment,showing good gas-sensing performance.First,the lower operating temperature?180??,followed by good selectivity.Not only can identify a variety of organic substances?formaldehyde,ethanol,acetone,etc.?,but also can effectively distinguish between benzene and its homologues.In addition,the response value is high?10 ppm o-xylene,response value³.8?,the lowest detectable to 0.5 ppm,and good stability.