Abstract
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 language | English |
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Pages (from-to) | 561-569 |
Number of pages | 9 |
Journal | Sensors and Actuators, B: Chemical |
Volume | 229 |
DOIs | |
Publication status | Published - 2016 Jun 28 |
Keywords
- 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