Study On Improving The Acetone Sensing Performance Of In₂O₃ Nanoparticles

Acetone as an organic compound,is often used in scientific research and industrial production.Acetone is a highly volatile toxic gas,inhaled by the human body will stimulate the respiratory system and even damage the organs.In addition,acetone is not only inflammable and explosive,but also closely related to diabetes.It has become a new research topic to detect the content of acetone in exhale gas to assist the diagnosis and monitoring of diabetes.Therefore,it is of great significance to further explore and develop the acetone gas sensors.In₂O₃,a wide bandgap semiconductor material,with excellent physical and chemical properties and is widely used in the fields of photocatalysis,pollutant degradation and gas sensing.However,the In₂O₃based gas sensor still has many defects,such as low response value,high energy consumption and poor stability.So in order to improve the In₂O₃ gas sensing properties,make its can be applied in the actual production and life.In this paper,the original In₂O₃,Fe doped In₂O₃,Au and Cl co-doped In₂O₃,LaFeO₃/In₂O₃ composite,La₂O₃/In₂O₃composite and Fe₂O₃/In₂O₃ composite were prepared by sol-gel method,respectively,and investigated the effects of the above measures on the gas-sensing properties of In₂O₃.The conclusions are as follows:(1)A series of Fe doped In₂O₃ nanomaterials were prepared by sol-gel method.The molar content of Fe was 0,1%,5%,and 10%,respectively.The gas sensing of these materials to acetone was tested.Firstly,the optimum operating temperature of the gas sensors is 200?.The gas response value first increases with the increase of Fe doping amount and reaches the peak value at5%,and then decreases with the further increase of Fe doping amount.Compared with other proportions of Fe-In₂O₃ materials,the sensor with x=5%not only has the highest response value,but also better performance in selectivity and stability.The overall improvement of gas sensing properties may be attributed to the fact that the introduction of Fe changed the structure and morphology of the material to a certain extent,resulting in the increase of specific surface area and the formation of more oxygen vacancies,which provided more adsorption sites and positively promoted the gas sensing characteristics.(2)Different molar ratios(x=0,0.5%,1%,2%)of Au and Cl co-doped In₂O₃ nanomaterials were prepared by sol-gel method,in which the material with x=1%had a higher gas-sensing response to acetone,but the optimum operating temperature increased by tens of degrees Celsius compared with the original In₂O₃,which meant higher energy consumption.At the same time,the response recovery speed is not as fast as the original In₂O₃.The introduction of Au and Cl did not reduce the reaction activation energy and accelerate the reaction with the target gas as expected.But it might work better in high temperatures.(3)LaFeO₃/In₂O₃,La₂O₃/In₂O₃ and Fe₂O₃/In₂O₃ nanocomposites with different mole percentages have been prepared successively,among which Fe₂O₃/In₂O₃ nanocomposites show the highest gas response value to acetone,and Fe₂O₃/In₂O₃ composites with molar ratio x=15%have excellent performance in gas response,sensitivity and stability.The characterization results of TEM,BET and XPS show that heterostructure is formed at the interface of Fe₂O₃/In₂O₃ composite material.Electrons from Fe₂O₃ with higher Fermi energy level flow to In₂O₃ through the interface and form a accumulation layer on its surface,which provides more sites for oxygen adsorption in the air.