CO_2气氛中界限电流型氧传感器输出特性的研究

Study of Output Character of Limiting Current Oxygen Sensor in CO_2 Mixed Gas

本文对钇稳定ZrO2界限电流型氧传感器在高CO2低O2浓度气氛中的输出特性进行了研究.研究结果显示:在高CO2低O2浓度气氛中,给界限电流型氧传感器施加0.4～0.7V范围工作电压时,输出电流出现了第一饱和输出平台,且饱和输出电流与氧浓度的关系符合经典的理论公式;但当工作电压增加后,输出电流急剧增加,并在1.1～1.3V和1.5～1.7V工作电压范围内出现了第二和第三饱和输出平台.为此,本文尝试采用新的假设机理:在较高工作电压下,气体中的CO2在氧传感器Pt电极表面,气体中的CO2可能催化分解产生出附加新的氧分子浓度的设想的假设机理对试验数据进行了合理解释.同时也发现,由于N2的存在,会提高延迟了工作电压促使CO2产生分解的电压的作用.

The output character of ZrO2 oxygen sensor working in a mixed gas of low O2 and high CO2 concentration was studied. The theoretical analyses showed that in this mixed gas of low O2 and high CO2 concentration and the saturated output current of oxygen sensor fitted the classical theory formula at low voltage. But as the working voltage became high the saturated output current of the oxygen sensor sharply increased and appeared second saturated step in 1.1- 1.3 V and third saturated step in 1.5 - 1. 7 V. By means of mechanism of CO2 decomposition at high working voltage the examination results can be rationally explained. And in this test a new phenomenon was discovered that course of CO2 decomposition was delayed because of existence of N2 gas.