Compared with Pt/TiO2, tungsten-loaded Pt–W/TiO2 catalysts exhibit improved activity for NO and soot oxidation. Using catalysts prepared by an incipient wetness method, the tungsten loading effect was investigated using Brunauer–Emmett–Teller surface areas, X-ray diffraction, transmission electron microscopy (TEM), CO pulse chemisorption, H2 temperature-programmed reduction, NH3 temperature-programmed desorption (NH3-TPD), and pyridine Fourier transform infrared (FT-IR) spectroscopy. Loading tungsten on the Pt/TiO2 catalyst reduced the platinum particle size, as revealed in TEM images. CO pulse chemisorption showed that platinum was covered with tungsten and the dispersion of platinum decreased when 5 wt.% or more of tungsten was loaded. The NH3-TPD and pyridine-FT-IR results demonstrated that the number of strong acid sites and Brønsted acid sites in the catalyst were increased by the presence of tungsten. Therefore, a catalyst containing an appropriate amount of tungsten increased the dispersion of platinum, thereby increasing the number of active sites for NO and soot oxidation, and increased the acidity of the catalyst, thereby increasing the activity of soot oxidation by NO2 .
Bibliographical noteFunding Information:
Funding: This research was funded by the CEFV (Center for Environmentally Friendly Vehicle) as Global-Top Project of KMOE (Ministry of Environment, Korea).
Acknowledgments: This research was supported by the CEFV (Center for Environmentally Friendly Vehicle) as Global-Top Project of KMOE (Ministry of Environment, Korea).
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- Exhaust gas after-treatment
- Oxidation catalyst
- Particulate matter (PM)
- Platinum catalyst
ASJC Scopus subject areas
- Physical and Theoretical Chemistry