Preparation And Gas Sensing Properties Of Stannate-Based Gas Sensors

The stannate metal oxides have potential applications in the fields of capacitors,photocatalysis,moisture sensitivity and gas sensitivity.Meanwhile,the stannate can be modified by equivalent,non-equivalent metal doping to achieve selective response to a specific target gas.Therefore,it is of great theoretical and practical significance to control the morphology of stannate metal oxides,which could operate at lower working temperatures.and dope metal elements to improve gas sensing properties.ZnSnO3,Mn2SnO4 and PbSnO3 samples were prepared by hydrothermal synthesis with mild reaction conditions.The microstructure of the materials was systematically studied by XRD,SEM and XPS.Through the synthesis of ZnSnO3,Mn2SnO4 and PbSnO3,the working temperature was successively reduced,and the stannate-based gas sensor materials which can be used for ethanol detection at a lower optimal working temperature was explored.(1)The hollow spherical morphology of ZnSnO3 was prepared by chemically induced self-transformed Oswald ripening and chemical dehydration,and no surfactant or blocking agent was used in the synthesis.The regulation and optimization of morphology were carried out by changing the reaction temperature,reaction time and the concentration of sodium hydroxide.The synthesis mechanism and response mechanism of ZnSnO3 hollow spheres were analyzed.At an optimum operating temperature of 240?,the ZnSnO3 sample showed good selectivity response to ethanol gas,indicating that ZnSnO3 hollow sphere is a potential ethanol sensing material.(2)The cubic structure of MnSn(OH)6 was prepared by rapid coprecipitation and self-assembly of Sn4+ and Mn2+ under alkaline conditions.A cubic-like Mn2Sn4 sample was prepared by using MnSn(OH)6 as a precursor combined with chemical dehydration and volume shrinkage at high temperatures.The hydrothermal synthesis conditions were optimized,and the influence of synthesis conditions on the morphology and gas sensing properties of Mn2SnO4 was investigated.Then the doping of Co2+,Ni2+ and Cu2+ was carried out.The doping of metal ions improved the response of ethanol.At the optimum working temperature of 200 0C,the response of Ni-Mn2SnO4 to ethanol was increased by 53.9%compared with Mn2SnO4.(3)Controlled preparation of lead stannate nanoparticles was achieved by rapid adsorption of polyvinylpyrrolidone(pvp)on the surface of the material to inhibit crystal growth.The aggregation of lead stannate particles was adjusted by changing the reaction temperature,reaction time and molecular weight of PVP.The doping of metal ions improved the ethanol response.At the optimum working temperature of 160?,the ethanol response of Cu-PbSnO3 sample was better than that of pure PbSnO3 samples,which was 28.8%higher than that of Co-PbSnO3.However,the doping of Ni2+did not significantly improve the ethanol response of PbSnO3.