New insight into the promoting role of process on the CeO2–WO3/TiO2 catalyst for NO reduction with NH3 at low-temperature.

This study aimed at investigating the reason of high catalytic activity for CeO 2 –WO 3 /TiO 2 catalyst from the aspects of WO 3 interaction with other species and the NO oxidation process. Analysis by X-ray diffractometry, photoluminescence spectra, diffuse reflectance UV–visible, X-ray photoelectron spectroscopy, density functional theory calculations, electron paramagnetic resonance spectroscopy, temperature-programmed-desorption of NO and in situ diffuse reflectance infrared transform spectroscopy showed that WO 3 could interact with CeO 2 to improve the electron gaining capability of CeO 2 species. In addition, WO 3 species acted as electron donating groups to transfer the electrons to CeO 2 species. The two aspects enhanced the formation of reduced CeO 2 species to improve the formation of superoxide ions. Furthermore, the Ce species were the active sites for the NO adsorption and the superoxide ions over the catalyst needed oxidizing the adsorbed NO to improve the NO oxidation. This process was responsible for the high catalytic activity of CeO 2 –WO 3 /TiO 2 catalyst. [ABSTRACT FROM AUTHOR]