P2.0.3 Nanostructured Metal Oxides for High-Temperature Gas Sensing: Structural Stabilization in Porous Metal Oxides
- Event
- 14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
Nürnberg/Nuremberg, Germany - Chapter
- P2.0 Metal Oxide-based Sensors
- Author(s)
- D. Klaus, M. Tiemann, T. Wagner - Universität Paderborn, Naturwissenschaftliche Fakultät, Department Chemie (Germany)
- Pages
- 1264 - 1266
- DOI
- 10.5162/IMCS2012/P2.0.3
- ISBN
- 978-3-9813484-2-2
- Price
- free
Abstract
As recently shown, nanostructured SnO2 and In2O3 prepared by nanocasting exhibit higher thermal structural stability than their non-ordered counterparts.In the presented work we will show a correlation of the thermal stability with the crystallite size of the nanostructure. In2O3is utilized as model material since preparation of nanocast phases with variable crystallite sizes is possible and it is a qualified sensing material. Two samples with different crystallite sizes but otherwise comparable structural features arethermally treated stepwise in a temperature range between 250°C and 700°C. The specific surface area (BET) is observed as a probe for the structural integrity of the material. Results show a shift of the mesostructure breakdown (steep decrease in BET surface area) to higher treatment temperatures for the sample with the larger lateral crystallite size. This breakdown is attributed to a coalescence-based growth mechanism. A linear decrease in surface area observed for both samples is assigned to Ostwald ripening which leads to a smoothing of the inner surfaces and a sealing of the micropores in the walls of the nanocast material.