Antimony Doping in SnO₂ Nanoparticles for Sensitive NO₂ Sensors.

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Developing cost-effective nitrogen dioxide (NO2) sensors with parts per billion (ppb)-level limit of detection (LOD) is critical for monitoring this toxic gas.
• Tin dioxide (SnO2) based sensors show promise but face challenges like poor selectivity, high operating temperatures, and moisture sensitivity.

Purpose of the Study:

• To synthesize high-performance antimony-doped tin dioxide (Sb-doped SnO2) sensors.
• To investigate the effect of antimony doping on the sensing properties of SnO2 for NO2 detection.
• To optimize sensor performance for enhanced selectivity, sensitivity, and stability.

Main Methods:

• Hydrothermal synthesis of Sb-doped SnO2 nanoparticles.
• Characterization of crystalline structure and nanoparticle size.
• Fabrication and testing of gas sensors under varying temperatures and humidity.
• Density functional theory (DFT) calculations to understand doping effects.

Main Results:

• Sb-doped SnO2 sensors exhibited rutile tetragonal crystalline structures with fine nanoparticles.
• Optimal annealing at 300 °C and specific doping concentrations (0.1-2.0 atom %) enhanced sensor performance.
• Sensors showed prominent selectivity towards NO2, with peak responses varying with temperature and doping.
• The SnO2:0.1%Sb sensor demonstrated excellent stability, a high response (2.65 × 10^4), rapid response/recovery times (153 s/11 s), and a low LOD (20 ppb) at 75 °C.
• DFT calculations confirmed that moderate Sb doping enhances NO2 adsorption.

Conclusions:

• Antimony doping effectively improves the performance of SnO2-based NO2 sensors.
• Optimized Sb-doped SnO2 sensors offer a cost-effective solution for ppb-level NO2 detection.
• The developed sensors exhibit enhanced selectivity, sensitivity, and stability, making them suitable for environmental monitoring applications.