posted on 2024-02-15, 01:43authored byHong Zhang, Yanqing Liu, Hailin Su, Yuelong Zhu, Haowei Zhu, Shibin Nie, Liangji Xu
In this work, unusual
potentiometric hydrogen sensing of mixed
conducting Ba0.5Sr0.5Co0.8Fe0.2O3–δ was reported. Inspired
by the unusual polarity, a dual sensing electrode (SE) potentiometric
hydrogen sensor was fabricated by pairing Ba0.5Sr0.5Co0.8Fe0.2O3–δ with electronic conducting ZnO to enhance the hydrogen response.
Hydrogen sensing measurements suggested that significantly higher
response, larger sensitivity, and lower limit of detection (LOD) were
achieved by the dual SE sensor when compared with the single SE sensor
based on Ba0.5Sr0.5Co0.8Fe0.2O3–δ or ZnO. A high response of
97.3 mV for 500 ppm hydrogen and a low LOD of 2.5 ppm were obtained
by the dual SE sensor at 450 °C. Furthermore, the effect of the
Fe doping concentration in Ba0.5Sr0.5Co1–yFeyO3–δ (y = 0.2, 0.5,
and 0.8) on hydrogen sensing response was investigated. The potentiometric
response values to hydrogen increased monotonically with increasing
Fe doping concentration. With the Fe/Co atomic ratio increased from
0.25 to 4, the responses to 500 ppm hydrogen raised by 69.6 and 94%
at 350 and 450 °C, respectively. The sensing behaviors of unusual
Ba0.5Sr0.5Co1–yFeyO3–δ may be ascribed to the predominant surface electrostatic effect.
These results show that mixed conducting Ba0.5Sr0.5Co1–yFeyO3–δ is desirable for developing
high-performance dual SE hydrogen sensors.