7. PTCR-Co Ceramics as Chemical Sensors

  1. Sheng Yao,
  2. Bruce Tuttle,
  3. Clive Randall and
  4. Dwight Viehland
  1. Zhi-Gang Zhou1,
  2. Zi-Long Tang2 and
  3. Zhong-Tai Zhang3

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291252.ch7

Advances in Electronic Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 26, Number 5

Advances in Electronic Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 26, Number 5

How to Cite

Zhou, Z.-G., Tang, Z.-L. and Zhang, Z.-T. (2005) PTCR-Co Ceramics as Chemical Sensors, in Advances in Electronic Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 26, Number 5 (eds S. Yao, B. Tuttle, C. Randall and D. Viehland), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291252.ch7

Author Information

  1. 1

    State Key Laboratory of Fine Ceramics and New Processing Department of Materials Science and Engineering Tsinghuna University Haidian District Beijing 100084, China

  2. 2

    State Key Laboratory of Fine Ceramics and New Processing Department of Materials Science and Engineering Tsinghua University Haidian District Beijing 100084, China

  3. 3

    State Key Laboratory of Fine Ceramics and New Processing Department of Materials Science and Engineering Tsinghua University Haidian District Beijing 100084, China

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2005

ISBN Information

Print ISBN: 9781574982350

Online ISBN: 9780470291252

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Keywords:

  • capable;
  • ceramics;
  • semiconducting;
  • phenomenon;
  • concentration

Summary

A new CO gas sensor of Perovskite-type oxide, semiconducting doped BaTiO3 based PTCR ceramics was studied. PTCR ceramic is capable of detecting carbon monoxide in the concentration range of 1–5% in the PTCR / NTCR region below/above the critical temperature, by means of higher barrier potential of PTCR / NTCR effect. The phenomenon is based on anionic adsorption, the extreme activity of the oxygen atoms at the surfaces of grain boundaries at the lower temperature while the bulk defect structures are frozen-in. The interaction between CO gases with the oxygen at the surface layer of the PTCR ceramics participates in the sensing reaction, and the itinerant electron comes from the conduction band of the n-type semiconducting ceramics. The creation of the new electron traps in the grain boundaries bring about to a decrease in resistivity of the material. The physisorption between the CO gas on the surface of the PTCR grains is the key for the ceramics working at lower temperature. The adsorption of CO gas on PTCR ceramics and mechanism of PTCR-CO working in lower temperature as well as kinetic process of defects are discussed.