High Performance Mixed Potential Type NO₂ Gas Sensor Based on Porous YSZ Layer Formed with Graphite Doping

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Sensing

Background:

• Nitrogen dioxide (NO2) is a critical air pollutant.
• Development of sensitive and selective NO2 sensors is essential for environmental monitoring.
• Mixed potential sensors offer a promising approach for gas detection.

Purpose of the Study:

• To fabricate and characterize high-performance mixed potential type NO2 sensors.
• To investigate the effect of graphite doping on sensor performance.
• To evaluate sensor response, linearity, repeatability, and cross-sensitivity.

Main Methods:

• Fabrication of porous yttria-stabilized zirconia (YSZ) layers doped with graphite.
• Preparation of LaFeO3 sensing electrode via citrate sol-gel method.
• Characterization using X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM).
• Performance evaluation of mixed potential NO2 sensors.

Main Results:

• The sensor doped with 3 wt% graphite exhibited the highest response (-76.4 mV to 80 ppm NO2).
• A linear relationship was observed between sensor response and the logarithm of NO2 concentration (10-200 ppm).
• The developed sensor demonstrated good repeatability and cross-sensitivity.

Conclusions:

• Graphite doping significantly enhances the performance of mixed potential NO2 sensors.
• The fabricated sensor shows potential for accurate and reliable NO2 detection.
• Further research can optimize sensor design for improved gas sensing applications.