Mesoporous tin oxide nanospheres for a NO_x in air sensor

Mesoporous tin oxide (SnO₂) with a high surface area of 147.5 m²/g has been successfully synthesized via self-assembly process, combining the driven forces of water-evaporation and molecular interactions. Scanning electron microscope, X-ray diffraction, transmission electron micrograph, Fourier transform infrared and Brunauer-Emmett-Teller were employed to analyze the morphology and crystal structure of the as-synthesized mesoporous materials. As a gas sensor, mesoporous SnO₂ shows impressive performances towards NO_x gas with high selectivity and stability as well as ultra high sensitivity about 94.3 to 10 ppm NO_xgas at 300 °C. The best response time of the sample S-500 is about 3.4 s to 10 ppm NO_xat 450°C. (paper)