A highly selective ammonia gas sensor using surface-ruthenated zinc oxide

Preparation and characterisation of a highly selective surface-ruthenated z inc oxide sensor for ammonia in trace levels is demonstrated. The introduct ion of some RuO linkages on the surface of ZnO leads to a dramatic enhancem ent in the sensitivity (S) to 1000 ppm level of ammonia at 300 degrees C (S = 440) as compared to the similar response obtained for pure ZnO (S = 1.5) . A systematic study using various characterisation techniques such as EDAX , SEM, CV and XPS indicates the key role played by the amount and distribut ion of Ru species on the surface. (C) 1999 Elsevier Science S.A. All rights reserved.