Redox Pathways for HCOOH Decomposition over CeO2 Surfaces
The reaction of HCOOH, the simplest C-1 carboxylic acid, has been studied on oxidized (CeO2) and reduced cerium oxide (CeOX) thin films. HCOOH has been proposed as an important C1 precursor to the formation of CO2 and H2 in the water-gas-shift (WGS) reaction, in which ceria is also used as a stable support rich in oxygen. The HCOOH is observed to adsorb by way of a formate intermediate species (HCOO-) through the dissociation of the acidic H over both CeO2 (Ce4+) and CeOX (Ce4+/Ce3+) surfaces. On the fully oxidized CeO2 surface, this H species reacts with surface O and desorbs as H2O when the temperature is <300 K. In addition to water, temperature programmed desorption spectra indicate the evolution of CO2 and H2 between 350 and 400 K followed by CO desorption in two regimes at 450 and 525 K. On reduced ceria, only CO and H2 were produced between 450 and 600 K. The reaction of HCOOH with ceria therefore leads to both the reduction of the oxide, through the formation of H2O and CO2, and oxidation of the oxide, through decomposition to H2 and CO, depending on the initial state of the ceria. C K-edge near-edge X-ray absorption fine structure and soft X-ray photoelectron spectroscopy indicate that formate and -OH were the only surface intermediates.
- Research Organization:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 960117
- Report Number(s):
- BNL--83103-2009-JA
- Journal Information:
- Journal of Physical Chemistry C, Journal Name: Journal of Physical Chemistry C Journal Issue: 26 Vol. 112; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- English
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