颗粒线度和非谐效应对传感器电极材料导电性能及其热稳定性的影响

本文考虑到原子的非简谐振动,应用固体物理理论和方法,研究了氧传感器多孔电极材料导电性能及热稳定性随温度和颗粒线度的变化规律,探讨原子非简谐振动和材料颗粒线度的影响.结果表明:(1)多孔Pt电极材料的电导率随温度的升高而非线性减小;电导率随颗粒半径的增大而非线性增大;电导率随时间增长而减小,但变化极小;(2)多孔Pt电极材料的电导率远小于Pt纳米材料的电导率,也小于块状Pt电极材料的电导率,且颗粒越小,颗粒线度效应越显著;(3)电导率的温度稳定性系数随温度的升高和颗粒线度的减小以及表面层参数的增大而非线性减小,即温度越高、颗粒线度越小、表面层参数越大,电极材料导电性的热稳定性越好;(4)表面层的存在使电导率降低,且降低情况与温度和颗粒线度有关,即颗粒越小,温度越低,电导率下降越明显;非简谐效应对电极材料的电导率几乎没有影响.

Effect of particle linearity and anharmonicity on the conductivity and thermal stability of electrode material of sensor

Taking into account the atomic anharmonic vibration, this paper applies solid-state physics theories and methods to study the changes in the conductivity and thermal stability of the porous electrode material of the oxygen sensor with temperature and particle linearity. Furthermore, the effect of atomic anharmonic vibration and particle linearity are discussed. The results show that: Firstly, the conductivity of porous Pt electrode materials decreases nonlinearly with increasing temperature, increases nonlinearly with increasing particle radius, and decreases with time but the change is very small. Secondly, the conductivity of porous Pt electrode materials is much smaller than that of Pt nanomaterials, and also smaller than that of bulk Pt electrode materials. The smaller the particles, the more significant the particle linearity effect. Thirdly, the temperature stability coefficient of conductivity decreases nonlinearly with increasing temperature, decreasing particle linearity and increasing surface effect parameters, that is, the higher the temperature, the smaller the particle size, and the larger the surface effect parameter, the better the thermal stability of conductivity of the electrode materials. Finally, the surface layer reduces the conductivity of the materials, and the decrease is related to temperature and particle linearity, that is, the lower the temperature, the smaller the particle, the more obvious the decrease of conductivity. The anharmonicity has almost no effect on the conductivity of the electrode materials.