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Pollutant trapping studies. 1—Resonance and spontaneous Raman spectra of the decomposition products of nitrogen dioxide on oxide surfaces
Author(s) -
Cooney Ralph P.,
Tsai Peter
Publication year - 1980
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250090109
Subject(s) - raman spectroscopy , chemistry , zeolite , decomposition , nitrate , inorganic chemistry , oxide , nitrogen , adsorption , photochemistry , analytical chemistry (journal) , catalysis , organic chemistry , physics , optics
The products of the surface decomposition of NO 2 /N 2 O 4 on zeolites X and A and γ‐alumina have been investigated using Raman spectroscopy. On the zeolite surfaces results indicate that a self‐ionization surface reaction occurs to generate nitrate (NO 3 − ) and nitrosonium (NO + ) ions. The extent of self‐ionization of NO 2 /N 2 O 4 appears to be far greater for the zeolitic absorbed phase than for the liquid phase. The nitrate appears to be held on cation sites while the nitrosonium ion is associated with the zeolitic oxide framework. Two different nitrate species form on zeolite A while only one nitrate species was detected on zeolite X. In the zeolite systems the spectra of adsorbed NO + were resonance enhanced using shorter wavelength exciting lines while the nitrate spectra were conventional (spontaneous) Raman spectra. On γ‐alumina the products of the surface decomposition of NO 2 /N 2 O 4 consist of three distinct types of surface nitrate with NO + not being detected.