Preparation,Characterization And Gas Sensing Properties Of Pr-doped ZnO/SnO₂ Nanoflowers

Methanol is a kind of colorless,alcohol-odor gas that is widely used in industrial production especially in the manufacture of formaldehyde and pesticides.It can also be used as an extractant for organic matter and a denaturant for alcohol.However,once the methanol leaks,it can form an explosive mixture when mixed with air.It have the danger of burning and exploding if the heat source and the light flame exist.In addition,if the human body inhales the methanol gas,there will be methanol poisoning phenomenon: paralysis,blurred consciousness and sudden drop of vision.Therefore,the timely detection of methanol gas has great significance for protecting human health and life safety.Tin oxide（SnO₂）and zinc oxide（ZnO）are important gas sensing materials due to their advantages of heat resistance,corrosion resistance and low cost ect,and have been widely studied in the field of gas sensors.However at the same time,the traditional ZnO and SnO₂ gas sensors have the disadvantages of low response,poor selectivity,and high operating temperature,which have inhibited their application in actual production and life.Studies have shown that the composition of the material,microstructure,surface defects and surface modification and other factors have an important impact on the gas sensor performance.Therefore,in this paper,Pr-doped ZnO/SnO₂ was prepared by the simultaneous doping of two semiconductors with metal ions,and its gas sensitivity was tested.The main research work is as follows:ZnO/SnO₂ and Pr-doped ZnO/SnO₂ nanoflowers were fabricated through a facile two-step method.The samples were characterized by XRD,EDX,XPS,SEM and TEM analysis.The gas sensing behaviors of the sensors were systematically investigated.Compared with ZnO/SnO₂ samples,Pr-doped ZnO/SnO₂ exhibit improved sensing performance at 200?C,and the sensors was proved to be excellent in selectivity to methanol.The methanol sensing mechanism of Pr-doped ZnO/SnO₂ nanoflowers is discussed,too.This work combines compounding and doping,which is very innovative and challenging.