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.