کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
55723 | 47063 | 2011 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Support effect on the NOx storage and sulfur-resisting performance of the NOx trap catalysts Pt/Li/TiO2–MOx (M = Al, Zr, Si, Sn) Support effect on the NOx storage and sulfur-resisting performance of the NOx trap catalysts Pt/Li/TiO2–MOx (M = Al, Zr, Si, Sn)](/preview/png/55723.png)
A series of Li-based lean-burn NOx trap (LNT) catalysts Pt/Li/TiO2–MOx (M = Al, Zr, Si, Sn) were prepared by sequential impregnation with the supports TiO2–MOx synthesized by co-precipitation. The support effect on the NOx storage and sulfur-resisting performance of Pt/Li/TiO2–MOx catalysts was investigated carefully. The NOx storage capacity of fresh Pt/Li/TiO2 is greatly improved by doping with Al2O3 or ZrO2 due to the remarkably increased specific surface area and the oxidation ability of the catalysts. HR-TEM and H2-chemisorption results reveal that the oxidation ability of Pt/Li/TiO2–MOx is mainly determined by Pt crystallite size. Larger Pt crystallites correspond to stronger oxidation ability. The regeneration of sulfated Pt/Li/TiO2–MOx strongly depends on the total acidity of the supports, including Brønsted and Lewis acid; the supports with larger acidity possess higher ability of sulfur-resistance and regeneration. The results of in situ DRIFTS show that over Pt/Li/TiO2–MOx (M = Al, Zr, Si, Sn) NOx is mainly stored as ionic nitrate species at 350 °C. Taking the NSC and regeneration ability into account, the catalyst Pt/Li/TiO2–Al2O3 is the most promising one for practical application.
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► The BET area and acidity of TiO2 are increased by the addition of MOx (M = Al/Zr/Si).
► The NOx storage capacity of Pt/Li/TiO2 is enhanced by MOx(M = Al/Zr/Si/Sn) addition.
► The ability of the catalysts for NO to NO2 oxidation is related to Pt particle size.
► The sulfur-resistance and regeneration of the catalysts depends on support acidity.
Journal: Catalysis Today - Volume 175, Issue 1, 25 October 2011, Pages 72–77