Patent ID: 8974657
Filing Date: 2015-03-10
Classification: G01N

Abstract:
1. A method for amperometrically detecting the concentration of one or more nitrogen oxides (NOX) and/or ammonia (NH3) in a gaseous oxidizing atmosphere, comprising: exposing an amperometric sensor to the gaseous atmosphere, wherein the sensor includes wherein the sensing and counter electrode layers are positioned on opposite sides of the porous electrolyte, and the sensing electrode layer is exposed to the gaseous atmosphere, and further wherein the ceramic phase of the sensing electrode layer comprises Gd or Sm-doped ceria, and the metallic phase of the sensing electrode layer comprises Pt, Pd, or an alloy or mixture thereof; applying a voltage bias between the sensing electrode and counter electrode layers of about 0.1 to about 1 volt, such that oxygen ion current flows through a thickness of the porous electrolyte layer and the oxygen ions are oxidized to oxygen gas at the counter electrode; measuring the resulting current through the sensor, wherein the oxygen gas from the counter electrode is vented from the sensor through the porous electrolyte membrane; and determining the concentration of nitrogen oxides (NOX) and/or ammonia (NH3) based on the measured current.