极限电流氧传感器中Pt／ZrO_2电极的极化

Polarization of Pt/ZrO 2 Electrode in Limiting Current Oxygen Sensor

用“三电极”法测试了Ｐｔ／ＺｒＯ２电极在４００～６００℃温度范围内分别充作阴、阳极时的极化规律。用数学处理将该电极的极化分离为电化学极化和欧姆极化两部分，讨论了气氛、工作电流、温度对它们的影响。得出该电极适用于高工作温度、低工作电流情形。指出设计使用于低温、高氧分压下的极限电流氧传感器，如选用Ｐｔ／ＺｒＯ２电极应特别注意扩散障的结构。

The cathode and anode polarizations of Pt/ZrO 2 electrode with common ZrO 2 oxygen sensor were studied by ‘three-electrode-method' within 400～600℃. The over-potentials were divided into electrochemical and ohmic parts with mathematical treatment. The influences of oxygen partial pressure, electrical current and temperature on the polarizations were discussed. It was derived that the electrode was adaptable to the working condition of high temperature and low oxygen pressure. It was proposed that the designer of the limiting current oxygen sensor working in low temperature and high oxygen pressure should pay more attention to the structure of the diffusion barrier if the Pt/ZrO 2 electrode was used. Otherwise, more reactive electrode should be used.