Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 156-162 |
| Number of pages | 7 |
| Journal | Surface Science |
| Volume | 648 |
| DOIs | |
| State | Published - Jun 2016 |
Funding
F.T. acknowledges the funding support from the Chemical Sciences, Geoscience and Biosciences Division, Office of Basic Energy Sciences, Office of Sciences, the U.S. Department of Energy under grant No. DE-SC0014561 . Part of this research including the in situ IR work was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.
Keywords
- In situ study
- complete oxidation
- methane
- transition metal oxide