Promotion effect of ultraviolet light on NO + CO reaction over Pt/TiO2 and Pt/CeO2-TiO2 catalysts
Abstract
Pt catalysts supported on TiO2 and CeO2-TiO2 (Pt/TiO2 and Pt/CeO2-TiO2) were prepared by a two-step precipitation-deposition method, respectively. As compared to Pt/TiO2, Pt/CeO2-TiO2 exhibits a higher thermo-catalytic activity and stability for CO + NO reaction, and also exhibits a stronger effect of ultraviolet light (UV) on promoting this reaction. The in-situ FTIR results indicate that the doped CeO2 can significantly improve the adsorption of NO at Pt/CeO2-TiO2, while UV light further enhance the adsorption of NO and its activation. Based on the results of Raman spectrum, electron paramagnetic resonance and the X-ray photoelectron spectroscopy testing, it is proposed that UV irradiation can cause the increase in surface electron density of Pt nanoparticles by the photo-induced electron transfer from TiO2 to Pt. Moreover, the doped CeO2 can further improve the electron transfer from TiO2 to Pt through a process of Ce4+ → Ce3+ under UV irradiation, resulting in the adsorption and activation of CO and NO species at Pt/CeO2-TiO2. This result also indicates that the photo-excitation of supports can strengthen the strong interaction between support and metal nanoparticles, and then promote the thermo-catalytic reactivity of catalysts.
- Publication:
-
Applied Catalysis B: Environmental
- Pub Date:
- December 2015
- DOI:
- 10.1016/j.apcatb.2015.05.044
- Bibcode:
- 2015AppCB.179..395H
- Keywords:
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- Nitrogen monoxide reduction;
- Carbon monoxide oxidation;
- Platinum nanoparticles;
- Electron transfer;
- Photo-assisted effect