Defect Engineering for SnO2 Improves NO2 Gas Sensitivity by Plasma Spraying.

Large emissions of nitrogen dioxide (NO2) pose a significant threat to human health, Monitoring its content and implementing timely measures are crucial. Utilizing oxide semiconductors, such as tin dioxide (SnO2), has proven to be an effective way to detect and analyze NO2. The design and preparation of sensing materials with high sensitivity and excellent selectivity is the key to improve the detection efficiency. SnO2 nanopowders with small and uniform particle size, large specific surface area, adjustable defect content, and no impurities were prepared by a new plasma spraying method. The SnO2 nanopowders exhibit outstanding performance in detecting NO2 at a low temperature of 100 °C, the response to 5 ppm of NO2 reaches 48, and the material demonstrates rapid response and recovery times, coupled with excellent selectivity. The exceptional gas-sensitive properties can be attributed to the superior morphology and structure of SnO2. It provides more reaction sites for gas sensitive reactions, fast electron transport, a large number of charge carriers, and improved adsorption of the material to the target gas. This study provides valuable insights into nanomaterial preparation and the enhancement of gas-sensitive properties for SnO2.