贵金属Pd离子掺杂纳米ZnSnO3的氢敏性能及掺杂机理

为了提高ZnSnO3的氢敏性能,以共沉淀法制备ZnSnO3并对其进行了贵金属Pd2＋掺杂.采用X射线衍射仪（X-ray diffraction,XRD）及透射电镜（transmission electron microscopy,TEM）对制备的气敏材料进行结构及形貌表征,并使用静态配气法测试了掺杂前后ZnSnO3的氢敏性能.结果表明：掺杂Pd2＋可显著提高ZnSnO3的氢敏性能.在工作温度为240℃、浓度为300×10-6的条件下,Pd2＋掺杂纳米ZnSnO3对氢气的灵敏度为12,是未掺杂时的3倍.基于第一性原理探讨气敏机理,计算结果表明：Pd2＋掺杂改变了ZnSnO3能带间的电子运动状态,使ZnSnO3费米能级由0.725 eV移动到1.035 eV,在费米能级附近产生新的电子峰,使其电导性能在气敏反应过程中改变更为明显.Pd2＋掺杂还使ZnSnO3表面吸附氧的能力显著增加,对提高氢敏性能起到了关键作用.

Hydrogen Sensing Properties and Doping Mechanism of Nano ZnSnO3 Doped with Noble Metallic Pd Ions

To improve the hydrogen sensing properties of ZnSnO3,nano ZnSnO3 doped with Pd ions was prepared using coprecipitation method in this paper.The microstructure and morphology of the prepared gas-sensitive materials were characterized using X-ray diffraction（XRD） and transmission electron microscopy（TEM）,respectively.The hydrogen sensing properties of the undoped and Pd2＋ doped ZnSnO3 were investigated using the static volumetric method.Results show that doping of Pd ions can significantly improve the hydrogen sensing properties of ZnSnO3.At the operating temperature of 240 ℃ and with the concentration of 300×10-6,the sensitivity of Pd2＋-doped ZnSnO3 to hydrogen is 12,which is three times that of the undoped sample.Further investigation of the gas sensing mechanism based on first-principles was conducted and calculation results indicate that the electronic athletic state of ZnSnO3 is changed after Pd2＋ was doped.The Fermi energy shifted from 0.725 eV to 1.035 eV and a new electronic peak was formed near the Fermi energy,leading to greater variation of conductivity in the gas-sensing reaction process.In addition,doping of Pd2＋ remarkably enhances the competence of oxygen adsorption on the surface of ZnSnO3,which plays a crucial role in improving the hydrogen sensing properties of ZnSnO3.