Highly sensitive and selective detection of ppb-level NO2 using multi-shelled WO3 yolk-shell spheres

作者：Kim Jun Sik; Yoon Ji Wook; Hong Young Jun; Kang Yun Chan; Abdel Hady Faissal; Wazzan A A; Lee Jong Heun

来源：Sensors and Actuators B: Chemical , 2016, 229: 561-569.

DOI：10.1016/j.snb.2016.02.003

• WO3
• Yolk-shell sphere
• Oxide semiconductor
• NO2 sensor

Triple-shelled, double-shelled, and dense WO3 spheres were prepared by ultrasonic spray pyrolysis and their NO2 gas sensing characteristics were investigated. Triple-shelled WO3 yolk-shell spheres showed an unprecedentedly high response (resistance ratio =100-49.0) to 50 ppb NO2 at 100-200 degrees C with negligible cross-responses to 5 ppm acetone, CO, NH3, ethanol, and toluene, whereas dense WO3 spheres showed low NO2 response (8.9-3.1). The response and selectivity to NO2 were maintained in a highly humid (relative humidity 80%) atmosphere. The ultrahigh response and selectivity of triple-shelled WO3 spheres to several tens ppb levels NO2 was attributed to the enhanced gas accessibility of the yolk-shell morphology with thin and permeable multiple shells.

• 出版日期2016-6-28