Back to overview

Flame synthesis of TiO2-based gas sensors

English title Flame synthesis of TiO2-based gas sensors
Applicant Pratsinis Sotiris E.
Number 112111
Funding scheme Project funding (Div. I-III)
Research institution Institut für Verfahrenstechnik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Chemical Engineering
Start/End 01.04.2006 - 31.07.2007
Approved amount 96'192.00
Show all

Keywords (4)

Combustion synthesis of materials; Flame spray pyrolysis; nanoparticles; Gas sensing

Lay Summary (English)

Lay summary
The goal of the project is to systematically investigate flame synthesis of nanostructured materials for gas sensing. This research is motivated by the growing demand for low-priced gas sensors that can function under diverse conditions of temperature and humidity. Tighter emission, security and health control regulations require sensors of higher sensitivity, stability and selectivity at different environments. This poses a challenge on the efficient manufacture of these materials as particle properties such as size, composition, crystallinity and morphology need to be precisely controlled. Flame processes have high potential for sensors as they are capable of producing fine particles and films of high purity (e.g. optical fibers) with closely controlled properties (as has been shown by ours and other academic and industrial laboratories) at a rather low cost. Note that a number of commodities (carbon blacks, fumed silica and pigmentary TiO2) are made industrially with flame processes.

Nb- and Cu-doped TiO2 nanoparticles were produced by flame spray pyrolysis (FSP) and tested for sensing of CO and ethanol at 400 °C in dry air. The as-prepared powders were characterized by transmission electron microscopy, x-ray diffraction, Raman spectroscopy and nitrogen adsorption. Niobium stabilized the anatase phase and retarded grain growth up to 600 °C. Copper promoted rutile formation and an anatase to rutile transformation was already observed just above 400 °C during post-synthesis calcination. This was accompanied by a segregation of large (> 100 nm) CuO crystals which were initially small (< 5 nm) asperities on the titania surface. Pure as well as doped TiO2 showed an n-type signal to CO and ethanol. Both dopants improved the sensitivity towards CO over that of pure TiO2. In contrast, for ethanol a high increase in sensitivity was observed only for Nb/TiO2.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
113114 Thermal Analysis System for the Investigation of Nanoparticle-based Processes and Products 01.07.2006 R'EQUIP
100325 Non-agglomerated and Nanocoated Nanoparticles 01.08.2003 Project funding (Div. I-III)