NOx Sensing Characteristics of Semiconductor Gas Sensors under Controlled Oxygen Activity Conditions Using a Proton-Conducting Electrolyte
NOx Sensing Characteristics of Semiconductor Gas Sensors under Controlled Oxygen Activity Conditions Using a Proton-Conducting Electrolyte
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DOI：
10.1149/2.0361709jes
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发表时间：
2017
影响因子：
3.9
通讯作者：
M. Nagao;Kazuyo Kobayashi;P. Lv;S. Teranishi;T. Hibino
中科院分区：
文献类型：
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作者：
M. Nagao;Kazuyo Kobayashi;P. Lv;S. Teranishi;T. Hibino
通过将金属氧化物电极连接到质子导电的Sn0.9In0.1P2O7电解液中，然后在200 ℃下进行电极极化，研究了在NOx（NO和NO2）检测过程中WO 3和In 2 O3内部及其周围高度氧化和还原态的形成。质子的插入和释放发生在WO 3电极，而金属离子的氧化还原反应进行在In 2 O3电极。阴极极化下生成的氢钨青铜对NO和NO2不敏感，而阳极极化下生成的WO 3对NO和NO2敏感。这些气体的添加以类似的方式增加了欧姆电阻、电荷转移电阻和气体扩散电阻。随着外加电压的极性和大小的改变，In 2 O3的NOx敏感能力发生了显著的变化。在阴极极化条件下，在-0.5 ~-1.5V范围内，NO和NO2的加入降低了传感器的电阻，但在-2.0V时，由于In 3+还原为低价态，从-1.7V开始选择性地吸收NO2，传感器的电阻增加。H2、CO或nC 4 H10的敏感性，随着WO 3和In 2 O3粒径的减小，传感器对NO2的敏感性增强。
The formation of highly oxidative and reductive states within and around WO 3 and In 2 O 3 during detection of NO x (NO and NO 2) was investigated by attaching the metal oxide electrode to a proton-conducting Sn 0.9 In 0.1 P 2 O 7 electrolyte, followed by electrode polarization at 200 C. Proton insertion and release occurred at the WO 3 electrode, while metal-ion redox reactions proceeded at the In 2 O 3 electrode. Although the hydrogen tungsten bronze formed under cathodic polarization was insensitive to NO and NO 2, the WO 3 operating under anodic polarization possessed sensitivity toward NO and NO 2. Addition of these gases increased the ohmic, charge-transfer, and gas-diffusion resistances in a similar manner. The In 2 O 3 underwent significant changes in NO x sensing ability upon changes in polarity and magnitude of the applied voltage. In particular, under cathodic polarization, the sensor resistance decreased upon addition of NO and NO 2 in the range of–0.5 to–1.5 V, but increased upon addition at–2.0 V, due to reduction of In 3+ to lower valence states, which selectively absorbed NO 2 beginning at–1.7 V. The WO 3 and In 2 O 3 sensing abilities were not significantly affected by interference from O 2, H 2, CO, or nC 4 H 10, and the sensors became more sensitive toward NO 2 as the WO 3 and In 2 O 3 particle size decreased.