Novel Ru-Mg-Al-O Catalyst Derived from Hydrotalcite-like Compound for NO Storage/Decomposition/Reduction
详细信息 查看全文
- 作者：Lan Dong Li ; Jun Jie Yu ; Zheng Ping Hao ; Zhi Ping Xu
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：July 19, 2007
- 年：2007
- 卷：111
- 期：28
- 页码：10552 - 10559
- 全文大小：709K
- 年卷期：v.111,no.28(July 19, 2007)
- ISSN：1932-7455
文摘
Ru-Mg-Al hydrotalcite-like anionic clay (Mg/Al/Ru = 90:29:1) was successfully prepared with a constant-pH coprecipitation method. Calcination of a hydrotalcite-like precursor at 600 
C in the air gave rise to thewell-mixed oxide Ru-Mg-Al-O that possesses a good dispersion of Ru species. Ru-Mg-Al-O catalystafter suitable pretreatment exhibits quite high NOx storage capability in the temperature range of 250-400C, and the highest NOx storage capability of about 220 
mol g-1 is obtained at 350 C with flowing 790ppm NO and 8% O2 in N2 stream. Meanwhile, the decomposition of 25-60% NO to N2 as well as N2O isclearly observed on the catalyst at 300-400 C. In situ diffuse reflectance Fourier transform (DRIFT) spectraindicate that NOx is adsorbed and stored on a catalyst mainly in the form of various coordinated nitrites/nitrates. On the basis of the NOx adsorption-desorption profiles as well as the in situ DRIFTS spectra, wehave proposed a schematic outline for NOx storage and NO decomposition. Finally, the reduction of storedNOx species on the catalyst by H2 was carried out at 350 C, indicating that all adsorbed NOx species can bereadily reduced by hydrogen.
C in the air gave rise to thewell-mixed oxide Ru-Mg-Al-O that possesses a good dispersion of Ru species. Ru-Mg-Al-O catalystafter suitable pretreatment exhibits quite high NOx storage capability in the temperature range of 250-400C, and the highest NOx storage capability of about 220 mol g-1 is obtained at 350 C with flowing 790ppm NO and 8% O2 in N2 stream. Meanwhile, the decomposition of 25-60% NO to N2 as well as N2O isclearly observed on the catalyst at 300-400 C. In situ diffuse reflectance Fourier transform (DRIFT) spectraindicate that NOx is adsorbed and stored on a catalyst mainly in the form of various coordinated nitrites/nitrates. On the basis of the NOx adsorption-desorption profiles as well as the in situ DRIFTS spectra, wehave proposed a schematic outline for NOx storage and NO decomposition. Finally, the reduction of storedNOx species on the catalyst by H2 was carried out at 350 C, indicating that all adsorbed NOx species can bereadily reduced by hydrogen.