摘要
Through the impregnation method, Ag catalysts with different support (such as TiO<sub>2</sub> and γ-Al<sub>2</sub>O<sub>3</sub>) were prepared and then tested for catalytic oxidation of formaldehyde (HCHO) at low temperatures. The Ag/TiO<sub>2</sub> catalyst exhibited strong catalytic performance, converting HCHO to CO<sub>2</sub> and H<sub>2</sub>O at around 95°C. However, the Ag/Al<sub>2</sub>O<sub>3</sub> catalysts showed much lower activity and reached 100% conversion at 125°C. The Ag-based catalysts were next characterized by several methods (XRD, TEM, FT-R, BET and H<sub>2</sub>-TPR). Results of characterization revealed that support dramatically impacts the size and dispersion of Ag particles. The XRD analysis showed the existence of different peaks of the silver on the surface of Al<sub>2</sub>O<sub>3</sub> in the contrast with TiO<sub>2</sub> no specific peaks exist. Therefore, the size of the Ag particles and their dispersion are the most important factors that affect their catalytic performance for formaldehyde oxidation. In terms of catalytic performance for HCHO oxidation, the Ag/TiO<sub>2 </sub>catalyst possesses the best Ag dispersion, as well as the smallest Ag particle size.
Through the impregnation method, Ag catalysts with different support (such as TiO<sub>2</sub> and γ-Al<sub>2</sub>O<sub>3</sub>) were prepared and then tested for catalytic oxidation of formaldehyde (HCHO) at low temperatures. The Ag/TiO<sub>2</sub> catalyst exhibited strong catalytic performance, converting HCHO to CO<sub>2</sub> and H<sub>2</sub>O at around 95°C. However, the Ag/Al<sub>2</sub>O<sub>3</sub> catalysts showed much lower activity and reached 100% conversion at 125°C. The Ag-based catalysts were next characterized by several methods (XRD, TEM, FT-R, BET and H<sub>2</sub>-TPR). Results of characterization revealed that support dramatically impacts the size and dispersion of Ag particles. The XRD analysis showed the existence of different peaks of the silver on the surface of Al<sub>2</sub>O<sub>3</sub> in the contrast with TiO<sub>2</sub> no specific peaks exist. Therefore, the size of the Ag particles and their dispersion are the most important factors that affect their catalytic performance for formaldehyde oxidation. In terms of catalytic performance for HCHO oxidation, the Ag/TiO<sub>2 </sub>catalyst possesses the best Ag dispersion, as well as the smallest Ag particle size.
作者
Rached Ousji
Zouhaier Ksibi
Abdelhamid Ghorbel
Céline Fontaine
Rached Ousji;Zouhaier Ksibi;Abdelhamid Ghorbel;Céline Fontaine(Laboratory of Materials Chemistry and Catalysis, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia;Institute of Chemistry of Poitiers: Materials and Natural Resources (IC2MP), University of Poitiers, Poitiers, France)
