Study On Enhancing The Gas Sensitivity Of SnO₂ By Surface Modification And UV Excitiation

NO₂is the main cause of low-level atmospheric ozone and urban smog formation,and NO₂gas and water vapor can also cause acid rain.High-performance NO₂sensors are urgently needed to detect or monitor NO₂in the atmosphere.The acid ion-modified material can increase the specific surface area and defect state of the material.Ultraviolet light excites the composite material to increase the free electrons on the surface of the material,which is conducive to carrier migration and gas activation.It can improve the sensitive properties of the material and accelerate the response recovery speed.This paper mainly focuses on hollow structures,quantum dots,UV excitation,surface functionalization and other directions,including the following contents.(1)The SnO₂hollow nanospheres were prepared by a hydrothermal process,and then the morphologies and sensitive properties were characterized.It is found that SnO₂has an excellent response to NO₂,but along with a long recovery time.(2)The obtained SnO₂hollow nanospheres were acidified with different acids,and their morphologies and sensitivities toward NO₂were characterized.As expected,the SnO₂material has a significant improvement on NO₂gas.(3)Physically stir the prepared TiO₂quantum dots with S-SnO₂material to form sensitive composite materials.Various characterisations and gas-sensing tests were carried out to control the ratio of composite quantum dots.The optimum gas sensing performance of the sensor is obtained under ultraviolet excitation.This paper investigates the properties of gas-sensitive materials excited by UV light.First,the SnO₂hollow nanospheres were treated with different acids to functionalize the surface of the material and increase the specific surface area and defect state of the material.The obtained material is compounded with TiO₂quantum dots,and the gas is detected under the action of ultraviolet light excitation.The gas sensing results show that the gas sensitivity of S-SnO₂can be well improved by compositing a certain proportion of TiO₂quantum dots and the UV excitation.This work provides theoretical and experimental support for the study of novel UV light excites the gas sensor.