Sulfur Poisoning Mechanism of Steam Reforming Catalysts: an X-ray Absorption Near Edge Structure (XANES) Spectroscopic Study
The present XANES study aims at elucidating the roles of carbon deposits and metal sulfides in the catalyst deactivation in steam reforming reactions with the presence of sulfur. CeO{sub 2}-Al{sub 2}O{sub 3}-supported Ni and Rh-based catalysts were tested in steam reforming of liquid hydrocarbon fuel containing 350 ppm sulfur for H{sub 2} production at 800 C. The Rhcatalyst demonstrated much better sulfur tolerance than the Nicatalyst. XANES revealed that there are various sulfur species (metal sulfide, sulfonate, sulfate and organic sulfide) on the used Ni and Rhcatalysts. Metal sulfide and organic sulfide are the dominant sulfur species on the Nicatalyst whereas sulfonate and sulfate predominate on the Rhcatalyst. Meanwhile organic sulfide and sulfate are also observed on the support alone. Furthermore, there are more carbon deposits formed in the presence of sulfur on both catalysts. More carboxylgroups occur on the carbon deposits formed on the same catalyst when there is no sulfur in the fuel. From correlation analysis of the amounts of nickel sulfide and carbon deposits along with the relative catalytic activity loss, we conclude that sulfur causes the initial deactivation of the Nicatalyst by metal sulfide formation in the first few hours while build-up of carbon deposits contributes mainly to the subsequent deactivation.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1020021
- Report Number(s):
- BNL-95867-2011-JA; TRN: US201116%%5
- Journal Information:
- Physical Chemistry Chemical Physics, Vol. 12, Issue 21; ISSN 1463-9076
- Country of Publication:
- United States
- Language:
- English
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