Gas sensor e.g. ammonia sensor, for e.g. diesel combustion engine, has measuring electrode covered with catalyst e.g. selective catalytic-reduction catalyst, for chemical reaction of nitrogen oxides

摘要

The sensor has a sensor cell (2) comprising measuring electrodes (4, 5) exposed to a measuring gas. The measuring electrode (4) is covered with a catalyst (6) e.g. selective catalytic-reduction (SCR) catalyst, for a chemical reaction of nitrogen oxides such as nitrous oxide, nitrogen dioxide and ammonia. The catalyst is catalytically effective with respect to the reaction between the nitrogen oxides. An electrically insulating layer (7) is formed between the electrode (4) and the catalyst. The electrodes are formed from metal e.g. platinum and platinum-gold compound, and/or metal oxide.