Sub PPM Detection of NO₂ Using Strontium Doped Bismuth Ferrite Nanostructures

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Acceptor-doped ferrite perovskites are explored for gas sensing applications.
• Bismuth Ferrite (BiFeO3) nanostructures offer potential due to their unique properties.

Purpose of the Study:

• To investigate the NO2 sensing properties of strontium (Sr)-doped BiFeO3 nanostructures.
• To synthesize and characterize these nanostructures for chemoresistive gas sensor fabrication.

Main Methods:

• Synthesis of Sr-doped BiFeO3 nanostructures using a modified Pechini method.
• Characterization via X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS).
• Fabrication of chemoresistive gas sensors using a drop-coating technique.

Main Results:

• Achieved a maximum sensitivity of 5.2 towards 2 ppm NO2 at 260 °C.
• Response and recovery times recorded at 95 s and 280 s, respectively.
• Demonstrated a low limit of detection (LOD) of 200 ppb for the Bi0.8Sr0.2FeO3-δ (BSFO) sensor.

Conclusions:

• Sr-doped BiFeO3 nanostructures exhibit promising repeatability and selectivity for NO2 sensing.
• The developed sensor material shows potential for competitive gas sensing applications.
• A gas-sensing mechanism based on surface adsorption and reaction behavior was proposed.