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

The assembly of highly hydrophobic nanosized tungsten-containing MFI-type zeolite nanocrystals (W-MFI) in films and further use of the films for selective exhaust gas (CO, CO 2, NO, and NO 2 ) detection were investigated by operando IR spectroscopy. Because of the hydrophobic nature and presence of tungsten in the framework, the W-MFI films showed excellent sorption capacity toward all analytes, in comparison to the pure silica (Si-MFI) film. The high sensitivity of the W-MFI film toward low concentration of CO 2 and NO 2 (1–3 ppm) was demonstrated. In addition, the interactions between the analytes and zeolite films have been studied by quantum chemical calculation modeling of the W centers based on the density functional theory method.