Li 도핑된 NiO 합성 및 열전식 수소센서에의 적용

Synthesis of Li-doped NiO and its application of thermoelectric gas sensor

  • 한치환 (한국에너지기술연구원 센서소재연구센터) ;
  • 한상도 (한국에너지기술연구원 센서소재연구센터) ;
  • 김병권 (한국에너지기술연구원 센서소재연구센터)
  • Han, Chi-Hwan (Sensors and Materials Research Center, Korea Institute of Energy Research) ;
  • Han, Sang-Do (Sensors and Materials Research Center, Korea Institute of Energy Research) ;
  • Kim, Byung-Kwon (Sensors and Materials Research Center, Korea Institute of Energy Research)
  • 발행 : 2005.06.15

초록

Li-doped NiO was synthesized by molten salt method. $LiNO_3$-LiOH flux was used as a source for Li doping. $NiCl_2$ was added to the molten Li flux and then processed to make the Li-doped NiO material. Li:Ni ratios were maintained from 5:1 to 30:1 during the synthetic procedure and the Li doping amount of synthesized materials were found between 0.086-0.190 as a Li ion to Ni ion ratio. Li doping did not change the basic cubic structural characteristics of NiO as evidenced by XRD studies, however the lattice parameter decreased from 0.41769nm in pure NiO to 0.41271nm as Li doping amount increased. Hydrogen gas sensors were fabricated using these materials as thick films on alumina substrates. The half surface of each sensor was coated with the Pt catalyst. The sensor when exposed to the hydrogen gas blended in air, heated up the catalytic surface leaving rest half surface (without catalyst) cold. The thermoelectric voltage thus built up along the hot and cold surface of the Li-doped NiO made the basis for detecting hydrogen gas. The linearity of the voltage signal vs $H_2$ concentration was checked up to 4% of $H_2$ in air (as higher concentrations above 4.65% are explosive in air) using Li doped NiO of Li ion/Ni ion=0.111 as the sensor material. The response time T90 and the recovery time RT90 were less than 25 sec. There was minimum interference of other gases and hence $H_2$ gas can easily be detected.

키워드

참고문헌

  1. R. Schmidt and A. W. Brinkman: 'Preparation and characterisation of $NiMn_{2}O_{4}$ films', International Journal of Inorganic Materials, Vol. 3, 2001, pp. 1215-1217 https://doi.org/10.1016/S1466-6049(01)00131-3
  2. H. Sato, T. Minami, S. Takata and T. Yamada: 'Transparent conducting p-type NiO thin films prepared by magnetron sputtering', Thin Solid Films, Vol.236, 1993, pp. 27-31 https://doi.org/10.1016/0040-6090(93)90636-4
  3. W. Shin, N. Murayama, K. Ikeda S. Sago: 'Thermoelectric power generation using Li-doped NiO and (Ba, Sr)$PbO_{3}$ module', Journal of Power Sources, Vol. 103, 2001, pp 80-85 https://doi.org/10.1016/S0378-7753(01)00837-0
  4. M. Matsumiya, F. Qui, W. Shin, N. Izu, N. Murayama, S. Kanzaki: 'Thin-film Li-doped NiO for thermoelectric hydrogen gas sensor', Thin solid films, Vol. 419, 2002, pp. 213-217 https://doi.org/10.1016/S0040-6090(02)00762-9
  5. M. Matsumiya, W. Shin, N. Izu, N. Murayama: 'Nano-structured thin-film Pt catalyst for thermoelectric hydrogen gas sensor', Sensors & Actuators B, Vol. 93, 2003, pp. 309-315 https://doi.org/10.1016/S0925-4005(03)00223-5
  6. W. Shin, N. Murayama: 'High performance p-type thermoelectric oxide based NiO', Materials Letters, Vol.45, 2000, pp 302-306 https://doi.org/10.1016/S0167-577X(00)00122-1
  7. F. Qiu, W. Shin, M. Matsumiya, N. Izu, I. Matsubara, N. Murayama: 'Miniaturization of thermoelectric hydrogen sensor prepared on glass substrate with low-temperature crystallized SiGe film', Sensors & Actuators B, Vol. 103, 2004, pp 252-259 https://doi.org/10.1016/j.snb.2004.04.057
  8. W. Shin, M. Matsumiya, F. Qiu, N. Izu, N. Murayama: 'Thermoelectric gas sensor for detection of high hydrogen concentration', Sensors & Actuators B, Vol 97, 2004, pp 344-347 https://doi.org/10.1016/j.snb.2003.08.029
  9. F. Qui, W. Shin. M. Matsumiya, N. Izu, N. Murayama: 'Hydrogen-sensing properties of multi-layer device Pt/SiGe sputtered on oxidized silicon substrate', Materials Chemistry and Physics, Vol. 82, 2003, pp 575-582 https://doi.org/10.1016/S0254-0584(03)00317-1
  10. C. H. Han, Y. S. Hong, E. J. Kang, J. S. Shin, K. Kim: 'Synthesis and electrochemical properties of HT-LiCoO.8NiO.20z prepared by molten salt synthesis method using $0.59LiNO_{3}-0.4lLiOH system', Korean, Journal of Chemical Engineering, Vol. 18, 2001, pp 765-769. https://doi.org/10.1007/BF02706398