Metallic phases of cobalt-based catalysts in ethanol steam reforming: The effect of cerium oxide

Journal Article · Sat Feb 28 04:00:00 EST 2009 · Applied Catalysis. A, General, 355(1-2):69-77

DOI:https://doi.org/10.1016/j.apcata.2008.11.032· OSTI ID:953789

Lin, Sean S.-Y.; Kim, Do Heui; Ha, Su Y

The catalytic activity of cobalt in the production of hydrogen via ethanol steam reforming has been investigated in its relation to the crystalline structure of metallic cobalt. At a reaction temperature of 350 8C, the specific hydrogen production rates show that hexagonal close-packed (hcp) cobalt possesses higher activity than face-centered cubic (fcc) cobalt. However, at typical reaction temperatures (400– 500 8C) for ethanol steam reforming, hcp cobalt is transformed to less active fcc cobalt, as confirmed by in situ X-ray diffractometry (XRD). The addition of CeO2 promoter (10 wt.%) stabilizes the hcp cobalt structure at reforming temperatures up to 600 8C. Moreover, during the pre-reduction process, CeO2 promoter prevents sintering during the transformation of Co3O4 to hcp cobalt. Both reforming experiments and in situ diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS) showed that the surface reactions were modified by CeO2 promoter on 10% Ce–Co (hcp) to give a lower CO selectivity and a higher H2 yield as compared with the unpromoted hcp Co.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 953789
• Report Number(s): PNNL-SA-64624; VT0401000
• Journal Information: Applied Catalysis. A, General, 355(1-2):69-77, Journal Name: Applied Catalysis. A, General, 355(1-2):69-77 Journal Issue: 1-2 Vol. 355; ISSN ACAGE4; ISSN 0926-860X
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
CATALYSTS
CERIUM OXIDES
COBALT
CRYSTAL STRUCTURE
ETHANOL
HYDROGEN
INTERSTITIAL HYDROGEN GENERATION
PRODUCTION
PROMOTERS
SINTERING
SPECTROSCOPY
STEAM REFORMER PROCESSES
SURFACES
TEMPERATURE DEPENDENCE
TRANSFORMATIONS
X-RAY DIFFRACTION