Adsorbed water as key to room temperature gas-sensitive reactions in work function type sensors: the carbonate-carbon dioxide system

Citation
B. Ostrick et al., Adsorbed water as key to room temperature gas-sensitive reactions in work function type sensors: the carbonate-carbon dioxide system, SENS ACTU-B, 57(1-3), 1999, pp. 115-119
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences","Instrumentation & Measurement
Journal title
SENSORS AND ACTUATORS B-CHEMICAL
ISSN journal
0925-4005 → ACNP
Volume
57
Issue
1-3
Year of publication
1999
Pages
115 - 119
Database
ISI
SICI code
0925-4005(19990907)57:1-3<115:AWAKTR>2.0.ZU;2-I
Abstract
In this work, it was found that exposure of barium carbonate to carbon diox ide (0.003%-5%) as active gas in wet synthetic air as carrier gas leads to an increase in work function between 50 and 150 meV at room temperature. Ot her carbonates show a similar behaviour and lower sensitivities. Without hu midity in the carrier gas, the sensitivity of barium carbonate disappears. Measurements were performed on pressed pellets, thick films (10-100 mu m) a nd thin films (1-2 mu m) of the material using a Kelvin probe with gold gri d as reference electrode. The effect was found to be independent of prepara tion. Between 23 degrees C and 100 degrees C, maximum sensitivity is reache d at about 50 degrees C. The work function change is attributed to the form ation of dimeric HCO3- species which have been identified using diffuse ref lectance infrared fourier transform (DRIFT) spectroscopy. (C) 1999 Elsevier Science S.A. All rights reserved.