Hydrophobic Tungsten-Containing MFI-Type Zeolite Films for Exhaust Gas Detection

Abstract : The assembly of highly hydrophobic nanosized tungsten containing MFI type zeolite nanocrystals (W-MFI) in films, and their further use for selective exhaust gas (CO, CO2, NO and NO2) detection was investigated by operando IR spectroscopy. Due to the hydrophobic nature and the presence of tungsten in the framework, the W-MFI films showed excellent sorption capacity towards all analytes, in comparison to the pure silica (Si-MFI) film. The high sensitivity of the W-MFI film towards low concentration of CO2 and NO2 (1-3 ppm) was demonstrated. In addition, the interactions between the analytes and zeolite films have been studied by quantum chemical calculations modeling of the W centers based on the density functional theory method.