The enhancement of response speed by loading the noble metal into the sensing layer for FET-Type N O2 sensors

Hirofumi Inoue, Masayoshi Yuasa, Tetsuya Kida, Noboru Yamazoe, Kengo Shimanoe

Research output: Contribution to journalArticle

Abstract

In order to enhance the response speed, noble metal (Ru) loading into the W O3-NaN O2 sensing layer for the field effect transistor (FET)-based N O2 sensors was investigated. The sensing layer was prepared by heat-treating the mixture powder of NaN O2 and noble metal (Ru)-loaded W O3 at 300°C. The effects of loading amounts of the noble metal on N O2 sensing performances as well as the microstructure of the sensing layer have been examined. It was found that the optimization of the noble metal loading amount into the sensing layer was important for the improvement of 90% response-and recovery-times. Field emission scanning electron microscopy observations revealed that the sensing layer became porous with increasing noble metal loading amounts. However, extensive addition of Ru (above 0.2 wt % to W O3) into the sensing layer resulted in the degradation of sensing characteristics, although the sensing layer showed a highly porous structure. According to theoretical analysis based on Knudsen gas diffusion reported by Matsunaga, the diffusion of gas molecules into such a porous sensing layer is very fast. Therefore the obtained results suggested that the improvement of the response-and recovery-speeds is owing to the large contribution of noble metal nanoparticle to the electrochemical promotion rather than the diffusion of N O2 gas into the sensing layer.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume158
Issue number2
DOIs
Publication statusPublished - Jan 5 2011

Fingerprint

Precious metals
Field effect transistors
noble metals
field effect transistors
augmentation
sensors
Sensors
Gases
Recovery
Diffusion in gases
Metal nanoparticles
Field emission
Powders
recovery
Degradation
gaseous diffusion
Microstructure
Scanning electron microscopy
Molecules
promotion

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

Cite this

The enhancement of response speed by loading the noble metal into the sensing layer for FET-Type N O2 sensors. / Inoue, Hirofumi; Yuasa, Masayoshi; Kida, Tetsuya; Yamazoe, Noboru; Shimanoe, Kengo.

In: Journal of the Electrochemical Society, Vol. 158, No. 2, 05.01.2011.

Research output: Contribution to journalArticle

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