Time-dependence of the conductance of SnO2: Pt: SB in atmospheres containing oxygen, carbon monoxide and water vapour I. Non-oscillatory behaviour

被引：7

作者：

机构：

[1] Ionescu, R.

[2] Vancu, Ana

来源：

Ionescu, R. | 1600年 / Publ by Elsevier Science Publishers B.V., Amsterdam, Netherlands卷 / 74期

关键词：

Carbon monoxide - Vapors - Water;

D O I：

10.1016/0169-4332(94)90001-9

中图分类号：

学科分类号：

摘要：

The time-dependence of the conductance G (T) of SnO2:Pt:Sb gas sensors after introducing CO in atmospheres containing oxygen and water vapour was investigated. Depending on experimental conditions, different G (t) behaviours were observed over different temperature ranges: either monotonic increases towards steady-state values, or self-sustained oscillations. Part I describes and analyzes the non-oscillatory, Part II the oscillatory behaviour. A unitary model is proposed, which offers a qualitative explanation for both, by taking into account an assembly of interdependent surface phenomena, including adsorption, desorption, spill-over and chemical reactions of oxygen, carbon monoxide and water. The role of water vapor is emphasized. Though speculative, the model is consistent with a broad range of experimental results and it also allows for some general considerations about utilizing the SnO2: Pt: Sb material as CO sensor and as oxidation catalyst.

引用