不定比酸化物による化学ポテンシャルポンピング効果の考え方と,ペロブスカイト型La0.5Sr0.5FeO3によるNOxセンシングの機構 A Concept of Chemical Potential Pumping Effect of Nonstoichiometric Oxides and the NO<sub>x</sub> Sensing Mechanism of the Perovskite-Type La<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3</sub>

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Author(s)

Abstract

A concept of chemical potential pumping effect was introduced to describe the NO<sub>x</sub> sensing mechanism of oxide catalysts with high electronic conductivity and large carrier density. When NO<sub>x</sub> gas in a gas-stream decomposed on the surface of the catalyst oxides continuously, the high oxygen potential released by the decomposition of NO<sub>x</sub> stationarily covered the whole surface of the oxide. Then, the bulk oxide was equilibrated with the steady-state high oxygen potential of the surface, which was much larger than that determined by the oxygen pressure of the surrounding gas-phase. This effect was confirmed by the conductivity enhancement of La<sub>2</sub>CuO<sub>4</sub> and La<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3</sub> with NO<sub>2</sub> as well as nonstoichiometry variation of La<sub>0.5</sub>Sr<sub>0.5</sub>CoO<sub>3</sub> and EMF of galvanic cell with La<sub>0.6</sub>Sr<sub>0.4</sub>CoO<sub>3−d</sub>. It was shown that the chemical potential pumping effect appears essentially on dense materials while the effect is hardly observed on porous material with large surface relative. On La<sub>0.5</sub>Sr<sub>0.5</sub>FeO<sub>3</sub> as well as on La<sub>2</sub>CuO<sub>4</sub>, NO<sub>2</sub> was found to decompose into NO and O<sub>2</sub>, while NO was almost inactive on these oxides.

Journal

  • Electrochemistry

    Electrochemistry 74(12), 949-955, 2006

    The Electrochemical Society of Japan

Codes

  • NII Article ID (NAID)
    130002150999
  • NII NACSIS-CAT ID (NCID)
    AN00151637
  • Text Lang
    ENG
  • ISSN
    1344-3542
  • NDL Article ID
    8604897
  • NDL Source Classification
    ZP1(科学技術--化学・化学工業)
  • NDL Call No.
    Z17-14
  • Data Source
    NDL  J-STAGE 
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