Patent ID: 7306712
Filing Date: 2007-12-11
Classification: G01N

Abstract:
1. A gas sensor for measuring a hydrogen concentration of a gas atmosphere containing H 2 and H 2 O, comprising a proton-conductive polymer electrolyte layer, a first electrode and a second electrode formed in contact with the proton-conductive polymer electrolyte layer and sandwiching the proton conductive polymer electrolyte layer, a partition wall provided between the first electrode and the gas atmosphere to be measured, and a diffusion-controlling hole provided in the partition wall and extending through the partition wall between the first measuring electrode and the gas atmosphere to be measured, the gas sensor being characterized in that A/(B×C) is not less than 9.5×10 −5 mm −1 , where A (mm 2 ) is an opening area of the diffusion-controlling hole on a side toward the gas atmosphere to be measured, B (mm) is a length of the diffusion-controlling hole, and C (mm 2 ) is an area of the first electrode or that of the second electrode, whichever is smaller and wherein I 30 /I 20 is less than 1.2, where I 30 is a limiting current as measured with an atmosphere to be measured which contains H 2 in an amount of 50% by volume and H 2 O in an amount of 30% by volume, and I 20 is a limiting current as measured with an atmosphere to be measured which contains H 2 in an amount of 50% by volume and H 2 O in an amount of 20% by volume.