Nanosized Sn-MFI zeolite for selective detection of exhaust gases

摘要

The properties of tin containing MFI type zeolite nanocrystals (Sn-MFI) synthesized under hydrothermal conditions from colloidal suspensions, and further application for selective detection of automotive exhaust gases (CO, CO2, NOx) are reported. The properties of the Sn-MFI nanosized zeolite are compared with the pure silicalite-1 nanocrystals (Si-MFI) synthesized under identical conditions, and used as a reference. Additionally, both samples (Si-MFI and Sn-MFI) with high crystallinity and high porosity were stabilized in coating suspensions and deposited in films by spin-coating approach. The Si-MFI and Sn-MFI samples as self-supported pellets and thin films were exposed to different concentrations of exhaust gases in the presence of 100 ppm of water. The sorption behavior of the Sn-MFI and the Si-MFI towards CO, CO2, NO and NO2 gases was followed by in situ IR spectroscopy. The influence of the tin concentration in the zeolite nanocrystals and the type of assembly (self-supported pellets and films) on the gas detection was studied. The fast detection of NO2 with the Sn-MFI sample in comparison to the other gases implies that the tin containing zeolite could be considered for further use a selective material for detection of low concentrations of NO2 (0-20 ppm). (C) 2016 Elsevier Ltd. All rights reserved.