Effects of CoFe₂O₄ electrode microstructure on the sensing properties for mixed potential NH₃ sensor

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• 作者：Yu YuanAuthor Vitae ; Bing WangAuthor Vitae ; Chao WangAuthor Vitae ; Xiangdong LiAuthor Vitae ; Jinqiang HuangAuthor Vitae ; Haibo ZhangAuthor Vitae ; Feng XiaAuthor Vitae ; Jianzhong Xiao ; ^{jzxiao@mail.hust.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; ^{jzxiao@126.com" class="auth_mail" title="E-mail the corresponding author}Author Vitae
• 关键词：Mixed-potential ; NH3 sensor ; CoFe2O4 ; TPB ; Microstructure ; Co-sintered
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：239
• 期：Complete
• 页码：462-466
• 全文大小：1458 K

文摘

Mixed potential ammonia sensors based on 5YSZ (ZrO₂ doped 5 mol% Y₂O₃) were prepared, with ferrite CoFe₂O₄ as sensing electrode material. Co-sintering of electrode and electrolyte has been realized. Sensors with different electrode microstructure characterized by Environmental Scanning Electron Microscope (ESEM) were made by different sintering process, and its influences on the sensors’ performance were investigated. The co-sintered sensor, with a porous three dimensional network structure electrode and great adhesion with electrolyte, exhibits the largest response (about 81 mV for 320 ppm NH₃) and the highest NH₃ sensitivity (55 mV/decade) with the response time (8–10 s) and recovery time (10–12 s) at 450 °C, it also shows satisfying NH₃ selectivity compared with NO_x, and O₂ has few influence on the sensor responses. The enhancement of the NH₃ sensitivity may owe to the porous three dimensional network structures, which is beneficial to adsorption and diffusion of the target gas, and better bonded interface between the electrode and electrolyte also provides more quantity of triple-phase boundary (TPB).