Do Cu(II) ions need Al atoms in their environment to make CuSiBEA active in the SCR of NO by ethanol or propane? A spectroscopy and catalysis study

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Do Cu(II) ions need Al atoms in their environment to make CuSiBEA active in the SCR of NO by ethanol or propane? A spectroscopy and catalysis study

Stanislaw Dzwigaj - Nama Orang; Tetsuya Shishido - Nama Orang; Janusz Janas - Nama Orang; Jacek Gurgul - Nama Orang; Robert P. Socha - Nama Orang; Michel Che - Nama Orang;

Abstract.
The two-step postsynthesis method (creation of vacant T-sites and associated SiOH groups by
dealumination of BEA zeolite with nitric acid followed by incorporation of copper in the resulting SiBEA
by impregnation with an aqueous solution of copper nitrate) allows to obtain a CuSiBEA zeolite which
contains 0.8 Cu wt%. The incorporation of Cu(II) into the lattice of SiBEA is evidenced by XRD while the
concomitant consumption of SiOH groups is monitored by FTIR. The presence of mainly isolated
mononuclear Cu(II) in D2d-distorted tetrahedral symmetry is evidenced by diffuse reflectance UV–vis-
NIR, EXAFS and XANES. The CuSiBEA zeolite is active in the selective catalytic reduction (SCR) of NO with
ethanol or propane withmaximum NO conversion of 40 and 20% and selectivity toward N2 close to 80–90
and 90–100%, respectively. These results suggest that the SCR process occurs on isolated mononuclear
Cu(II) in D2d-distorted tetrahedral symmetry after Al atoms have been removed from the zeolite
structure. Thus, Cu(II) ions do not need Al atoms in their environment to be catalytically active. The lack of correlation between the SCR activity in presence of ethanol and the oxidation of NO to NO2 suggests that
the two reactions are more competitive than sequential. The higher activity of CuSiBEA with ethanol than
with propane may be due to different activation energies and/or reaction mechanisms.

Keywords: SiBEA zeolite, Copper, NO, Ethanol, Propane, FTIR, DR UV–vis-NIR, XAS.

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Judul Seri: Applied Catalysis B: Environmental
No. Panggil: -
Penerbit: London : Elsevier B.V.., 2009
Deskripsi Fisik: Applied Catalysis B: Environmental 85 (2009) 131–138
Bahasa: English
ISBN/ISSN: -
Klasifikasi: -
Tipe Isi: -
Tipe Media: -
Tipe Pembawa: -
Edisi: -
Subjek: KIMIA
Info Detail Spesifik: -
Pernyataan Tanggungjawab: agus

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Do Cu(II) ions need Al atoms in their environment to make CuSiBEA active in the SCR of NO by ethanol or propane? A spectroscopy and catalysis study

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