Spectroscopic IR, EPR, and operando DRIFT insights into surface reaction pathways of selective reduction of NO by propene over the Co-BEA zeolite

doi:10.1039/C1CP23038G

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punktacja MNiSW [2012 A]: 40

tytuł	Spectroscopic IR, EPR, and operando DRIFT insights into surface reaction pathways of selective reduction of NO by propene over the Co-BEA zeolite
autor	Pietrzyk Piotr , Dujardin Christophe, Góra-Marek Kinga , Granger Pascal, Sojka Zbigniew
tytuł czasopisma	Physical Chemistry Chemical Physics
tom	14
numer	7
data wydania	2012
strony	2203-2215
ISSN	1463-9076
eISSN	1463-9084
DOI	10.1039/C1CP23038G
adres URL	http://pubs.rsc.org/en/content/articlepdf/2012/cp/c1cp23038g
data dostępu	2015-04-29
język	angielski
język czasopisma	angielski
abstrakt w j. angielskim	Interaction of a Co–BEA catalyst with individual components (NO, C 3 H 6,CO,O 2) and mixtures simulating the real feed of the selective catalytic reduction (SCR) of nitric oxide in static and pulse experiments at variable temperatures was investigated by means of IR, EPR, and operando DRIFT spectroscopy coupled with QMS/GC analysis of the products. Speciation of cobalt active sites into Co( II ), mono- and polynuclear oxo-cobalt species as well as CoO clusters was quantified by IR using CO and NO as probe molecules. The key intermediates, by-products, and final products of the SCR reaction were identified and their spectroscopic signatures ascertained. Based on the spectroscopicoperando results, a concise mechanistic scheme of the selective catalytic reduction of nitric oxide by propene, triggered by a two-electron Co( II )/Co(0) redox couple, was developed. It consists of a complex network of the sequential/parallel selective reduction steps that are interlocked by the rival nonselective oxidation of the intermediates and their thermal decomposition. It has been shown that the SCR process is initiated by the chemoselective capture of NO from the reaction mixture by the cobalt active sites leading to the cobalt(II) dinitrosyls, which in the excess of oxygen are partially oxidized to surface nitrates and nitrites. N 2 Oisproduced by semi-decomposition of the dinitrosyl intermediates on the mononuclear centers, whereas NO 2 via NO oxidation on the polynuclear oxo-cobalt sites. Cyanide and isocyanate species, formed together with propene oxygenates in the course of the CQC bond scission, are the mechanistically pivotal reaction intermediates of C 3 H 6 interaction with the dinitrosyles and NO 3 /NO 2 surface species. Dinitrogen is produced by three main reaction routes involving oxidation of cyanides by NO/NO 2, reduction of dinitrosyls, nitrates, and nitrites by propene oxygenates (medium temperature range) or their reduction by carbon monoxide (high temperature range)
punktacja wydziałowa	40
wydział:instytut/zakład/katedra	Wydział Chemii : Zakład Chemii Nieorganicznej
typ	artykuł w czasopiśmie
podtyp	artykuł