Journal of information and communication convergence engineering

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
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Pd-doped $SnO_2$-based oxide semiconductor thick-film gas sensors prepared by three different catalyst-addition processes

  • Lee, Kyu-Chung (Department of Information Technology, Sungkyul University) ;
  • Hur, Chang-Wu (Department of Electronic Engineering, Mokwon University)
  • Published : 2009.03.30
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Abstract

Three different procedures for adding Pd compounds to $SnO_2$ particles have been investigated. These processes are: (1) coprecipitation; (2) dried powder impregnation; and (3) calcined powder impregnation. The microstructures of $SnO_2$ particles have been analyzed by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). In the coprecipitaion method, the process does not restrain the growth of $SnO_2$ particles and it forms huge agglomerates. In the dried powder impregnation method, the process restrains the growth of $SnO_2$ particles and the surfaces of the agglomerates have many minute pores. In the calcined powder impregnation method, the process restrains the growth of $SnO_2$ particles further and the agglomerates have a lot more minute pores. The sensitivity ($S=R_{air}/R_{gas}$) of the $SnO_2$ gas sensor made by the calcined powder impregnation process shows the highest value (S = 21.5 at 5350 ppm of $C_3H_8$) and the sensor also indicates the lowest operating temperature of around $410^{\circ}C$. It is believed that the best result is caused by the plenty of minute pores at the surface of the microstructure and by the catalyst Pd that is dispersed at the surface rather than the inside of the agglomerate. Schematic models of Pd distribution in and on the three different $SnO_2$ particles are presented.

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References

  1. K. Ihokura, and J. Watson, Stannic oxide gas sensor -Principles and applications, CRC Press 1994
  2. P. T. Moseley and B. C. Tofield, Solid state gas sensors, Adam Hilger, 1987
  3. N. yamazoe, "New approaches for improving semiconductor gas sensors," Sensors and Actuators B, Vol. 5, pp. 7-19,1991
  4. Y. S. Shyr, and W. R. Ernst, "Preparation of nonuniformly active catalysts," J Catalysis, Vol. 63,pp.425-432,1980 https://doi.org/10.1016/0021-9517(80)90096-2
  5. S. Matsushima, Y. Teraoka, N. Miura and N.Yamazoe, "Electronic interaction between metal additives and tin dioxide in tin-dioxide-based gas sensors," Jpn. J Appl. Phys., Vol. 27[10], pp. 1798-1802,1988 https://doi.org/10.1143/JJAP.27.1798
  6. L. V. Azaroff and J. J. Brophy, Electronic processes in materials, Mcgraw-Hill Inc., 1963
  7. J. H. Lee and S. J. Park, "Sn02 powder preparation from hydroxide and oxalate and its characterization," J Kor. Ceram. Soc., Vol. 27[2], pp. 274-282, 1990
  8. J H. Lee and S. J. Park, "Crystal structure ofTiOr Sn02 fine powders prepared by coprecipitation," J Kor. Ceram. Soc., Vol. 30[9], pp. 740-746,1993
  9. K. Lee, K.-R. Ryu and c.- W. Hur, 'Thick-film ammonia gas sensor with high sensitivity and excellent selectivity," The Korean Institute of Maritime Info. and Communicatn Sci., Vol. 2, pp. 22-25, 2004
  10. C. D. Wagner, W. M. Riggs, L. E. Davis, J. F. Moulder and G. E. Muilenberg, Handbook of xray photoelectron spectroscopy, Perkin-Elmer Co., 1979