Efficient ppt-Level H<sub>2</sub>S Gas Sensor Based on YSZ and α-Fe<sub>2</sub>O<sub>3</sub> Nanofoam Sensing Electrode
Xidong Hao, Xiangli Meng, Tianling Yu, Zihao Wang, Yinglin Wang, Shanfu Sun, Pengfei Cheng, Yintang Yang, Qianyong Yang
Abstract
Herein, porous α-Fe 2 O 3 nanofoam was successfully synthesized and used as a sensing electrode to fabricate a yttria-stabilized zirconia (YSZ) mixed-potential hydrogen sulfide (H 2 S) sensor for real-time monitoring of hazardous H 2 S gas. The sintering temperature was adjusted to modify the microstructure of the sensing electrode material and its electrochemical reaction intensity to H 2 S, enhancing the sensor’s performance. Among the tested materials, α-Fe 2 O 3 nanofoam sintered at 800 °C exhibited the highest electrochemical catalytic activity toward H 2 S in electrochemical tests, suggesting its suitability as a sensing electrode material for YSZ-based H 2 S sensors. The sensor incorporating α-Fe 2 O 3 nanofoam sintered at 800 °C achieved the highest response of −273 mV to 10 ppm of H 2 S at 625 °C. Moreover, this sensor exhibited a low detection limit of 100 ppt and, within the H 2 S concentration range of 0.5–10 ppm, a high sensitivity of −180.3 mV/decade, outperforming other reported YSZ-based H 2 S sensors. Furthermore, this fabricated sensor exhibited excellent repeatability, selectivity, and long-term stability, indicating its potential for industrial safety early warnings and precise environmental monitoring. This study provides a valuable reference for designing porous sensing electrode materials and enhancing the sensing performance of mixed-potential gas sensor.