Development of a porous layer catalytically activated for improving gas sensors performances

• Published in: Ceramics international 2007-01, Vol.33 (7), p.1199-1203
• Main Authors: Tulliani, J.M., Moggi, P.
• Format: Article
• Language: English
• Subjects: A. Films; B. Microstructure-final; Carbon monoxide; Catalysis; Chemistry; Colloidal state and disperse state; E. Sensors; Exact sciences and technology; General and physical chemistry; Porous materials; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2006.04.005

A screen-printed thick film was developed to be overlapped to a gas sensing device for preserving it from contamination and degradation occurring in hostile environments, and also for improving its selectivity to a single pollutant gas when exposed to a complex atmosphere. This protective layer incorporated Al 2O 3 doped with Cs or Ba oxides as a catalyst material for eliminating gaseous interfering species, precisely CO 2, to improve sensor response to CO. The best performances were obtained by depositing two, successive layers: the lower one, made of an alumina sol with a dispersed commercial α-alumina powder, just plays the role of protecting the sensitive material and electrodes from degradation, while the upper layer was obtained by the deposition of a screen-printable ink made of doped-alumina powders and is able to selectively adsorb CO 2, just allowing CO to interact at the sensing material surface.