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NH3 Oxidation Mechanism over Cu/SAPO-34 Catalysts Prepared by Different Methods.
- Source :
-
ChemCatChem . Jul2014, Vol. 6 Issue 7, p2074-2083. 10p. - Publication Year :
- 2014
-
Abstract
- NH3 oxidation mechanism and its inhibition effect on the selective catalytic reduction of NO x by NH3 (NH3-SCR) reaction over two series of Cu/SAPO-34 catalysts were studied. It was found that the different NO conversions were induced by the diverse NH3 oxidation degree. X-ray diffraction, scanning electron microscopy, H2 temperature-programmed reduction (H2-TPR), and CO diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS) analyses were conducted to estimate the Cu species distribution. The TPR results showed that the CuO species was dominant in impregnated Cu/SAPO-34 samples, and the ion-exchanged Cu/SAPO-34 samples contained more isolated Cu2+ species. Furthermore, H2-TPR, electron paramagnetic resonance, and CO-DRIFTS analyses were utilized to quantify the CuO, Cu2+, and Cu+ species. The results together with the kinetic results revealed the CuO is the active site for NH3 oxidation, and the NH3 oxidation over Cu/SAPO-34 sample consists two steps: (a) NO production; (b) further NO consumption by adsorbed NH3 species on Cu2+ sites. Finally, the inhibition of NH3 oxidation on NH3-SCR activity was explained and the NO conversion at high temperature was related to the Cu2+/CuO ratio in Cu/SAPO-34 sample. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18673880
- Volume :
- 6
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- ChemCatChem
- Publication Type :
- Academic Journal
- Accession number :
- 97053631
- Full Text :
- https://doi.org/10.1002/cctc.201402048