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Title: In situ studies of surface of NiFe2O4 catalyst during complete oxidation of methane

Here, NiFe2O4 with an inverse spinel structure exhibits high activity for a complete oxidation of methane at 400 °C–425 °C and a higher temperature. The surface of the catalyst and its adsorbates were well characterized with ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and in situ infrared spectroscopy (IR). In situ studies of the surface of NiFe2O4 using AP-XPS suggest the formation of methoxy-like and formate-like intermediates at a temperature lower than 200 °C, supported by the observed vibrational signatures in in situ IR studies. Evolutions of C1s photoemission features and the nominal atomic ratios of C/(Ni + Fe) of the catalyst surface suggest that the formate-like intermediate is transformed to product molecules CO2 and H2O in the temperature range of 250–300 °C. In situ studies suggest the formation of a spectator, – Olattice – CH2 – Olattice –. It strongly bonds to surface through C–O bonds and cannot be activated even at 400 °C.
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [4]
  1. Univ. of Kansas, Lawrence, KS (United States)
  2. Hubei Univ. of Technology, Wuhan (People's Republic of China)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. (Feng) [Univ. of Kansas, Lawrence, KS (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Surface Science
Additional Journal Information:
Journal Volume: 648; Journal Issue: C; Journal ID: ISSN 0039-6028
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY complete oxidation; transition metal oxide; methane; in situ study