Catalytic reduction of NO on copper/MCM-41 studied by in situ EXAFS and XANES

Y. J. Huang, H. Paul Wang, Jyh Fu Lee

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26 Citations (Scopus)

Abstract

Speciation of copper in the channels of MCM-41 during reduction of NO with CO at 473-773 K was studied by in situ extended X-ray absorption fine structural (EXAFS) and X-ray absorption near edge structural (XANES) spectroscopies in the present work. The component fitted (in situ) XANES spectra of the catalyst showed that about 72% of metallic copper (Cu(O)) in MCM-41 was oxidized to higher oxidation state coppers (Cu(II) (46%) and Cu(I) (26%)) during the NO reduction process (at 473 K). By EXAFS, we also found that in the NO reduction process, oxygen was inserted into the metallic copper matrix and led to a formation of the copper oxide species with a Cu-O bond distance of 1.93 Å which was greater than that of the model compound Cu2O (typically 1.86 Å). At 573-673 K, mainly Cu(II) was found in the channels of MCM-41. Nevertheless, at a higher temperature (e.g., 773 K), about 61% Cu(I), 31% Cu(II), and 8% Cu(O) with averaged Cu-Cu and Cu-O bond distances of 3.04 and 1.88 Å, respectively were observed, that might account for the high selectivity-to-decomposition (S/D) ratios for yields of N2 and CO2 in the catalytic reduction of NO with CO.

Original languageEnglish
Pages (from-to)1035-1041
Number of pages7
JournalChemosphere
Volume50
Issue number8
DOIs
Publication statusPublished - 2003 Mar 1

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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