GAS SENSOR AND GAS DETECTOR

申请公布号：

JP2000356614(A)

申请号：

JP20000110970

申请日期：

2000.04.12

申请公布日期：

2000.12.26

申请人：

OSAKA GAS CO LTD

发明人：

ONISHI HISAO;TABATA SOICHI;YOKOYAMA KOUTA

分类号：

G01N27/12;(IPC1-7):G01N27/12

主分类号：

G01N27/12

摘要：

PROBLEM TO BE SOLVED: To make detectable a very small content of methane without being affected by other combustible components by adjusting the content of platinum in a lower layer zone in a catalyst layer to be below a specific value, and adjusting the content of platinum in an upper layer zone to be above a specific value. SOLUTION: A lower layer part positioned at approximately less than 2μm from an oxide semiconductor surface in a catalyst layer, does not include platinum, or includes by not more than approximately 1 wt.%, and an upper layer positioned at approximately not less than 2μm from the oxide semiconductor surface includes approximately not less than 1.5 wt.% of platinum. The concentration of platinum in the lower layer part in the catalyst layer is less than about 1/4 of that of the upper layer part, to obtain the selectively to hydrogen and isobutane. For example, when the catalyst layer of approximately 400μm thick is formed, and the concentration of platinum in the upper layer part is approximately 5 wt.%, the concentration of platinum in the lower layer part within approximately 40μm from the oxide semiconductor surface is adjusted to be less than 1/4 with respect to that of the upper layer part to increase the sensitivity to methane. Thereby, a gas sensor is provided with a sensitivity to methane of 500 ppm, the same as that to hydrogen of 10,000 ppm and isobutane of 5,000 ppm.