Burr & Brown
NOx-decomposing electrode and NOx concentration-measuring apparatus
 Disclosed is a NOx concentration-measuring apparatus for measuring a NOx concentration by using a main pumping cell including an electrode (inner pumping electrode and outer pumping electrode) having no or low decomposing/reducing ability with respect to NOx to control an oxygen concentration in a measurement gas to have a predetermined value which substantially does not affect measurement of NOx component, and using a detecting electrode having certain or high decomposing/reducing ability with respect to NOx to decompose NOx so that an amount of oxygen produced during this process is measured, wherein the detecting electrode is a cermet electrode composed of an alloy of Pt--Rh and a ceramic component, and Pt and Rh are contained in a weight ratio of Pt:Rh=20:80 to 1:99. 
NGK Insulators, Ltd.
Y G G G
Y02A G01N G01N G01N
additional inventional inventional additional
Satoshi Kunihiko Nobuhide
Nishikawa Nakagaki Kato