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

Jun Sik Kim, Ji Wook Yoon, Young Jun Hong, Yun Chan Kang, Faissal Abdel-Hady, A. A. Wazzan, Jong Heun Lee

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62 Citations (Scopus)


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 °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.

Original languageEnglish
Pages (from-to)561-569
Number of pages9
JournalSensors and Actuators, B: Chemical
Publication statusPublished - 2016 Jun 28


  • NO sensor
  • Oxide semiconductor
  • WO
  • Yolk-shell sphere

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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