| 摘要 |
PROBLEM TO BE SOLVED: To detect total NOx by oxidizing NOx to an excessively oxidized state using a catalyst electrode until it is detected by a detection electrode and increasing the oxygen concentration by an oxygen pump electrode so that a peroxide cannot be decomposed. SOLUTION: A noble metal electrode is used as a nitrogen oxide conversion electrode 2 for a zirconia ion conductive solid electrolyte substrate 1, and a platinum counter electrode 3 is formed on the opposite surface of the substrate 1. An oxygen pump electrode 4 is formed on the same surface as the conversion electrode 2 and the platinum counter electrode 3 is formed on the opposite surface. Also, a noble metal electrode is formed as a nitrogen oxide detection electrode 6 on another zirconia substrate 5, a precious metal reference electrode 7 is formed on the opposite surface, and a noble metal oxide detection electrode 8 is formed on the same surface as the nitrogen oxide detection electrode 6. The reference electrode 7 and the detection electrode 8 are inactive and active to a nitrogen oxide and oxygen, respectively. The substrates 1 and 5 are adhered and sintered via a spacer with a similar solid electrolyte. A voltage to be applied to the conversion electrode 2 to oxidize the nitrogen oxide to an excessively oxidized state preferably ranges from 0.4 to 1.0 V. |
