Effect of Barium Loading on the Desulfation of Pt-BaO/Al2O3 Studied by H2 TPRX, TEM, Sulfur K-edge XANES, and in Situ TR-XRD

Journal Article · Thu Jun 01 00:00:00 EDT 2006 · Journal of Physical Chemistry B, 110(21):10441-10448

OSTI ID:883679

Kim, Do Heui; Szanyi, Janos; Kwak, Ja Hun; Szailer, Tamas; Hanson, Jonathan; Wang, Chong M; Peden, Charles HF

Desulfation processes were investigated over sulfated Pt BaO/Al2O3 with different barium loading (8 wt% and 20 wt%) by using H2 temperature programmed reaction (TPRX), transmission electron microscope (TEM) with energy dispersive spectroscopy (EDS), sulfur K-edge X-ray absorption near-edge spectroscopy (XANES), and in situ time-resolved X-ray diffraction (TR-XRD) techniques. Both sulfated samples (8 wt% and 20 wt%) form sulfate species (primarily BaSO4) as evidenced by S K-edge XANES and in situ TR-XRD. However, the desulfation behavior is strongly dependant on the barium loading. Sulfated Pt BaO(8)/Al2O3, consisting predominantly of surface BaO/BaCO3 species, displays more facile desulfation by H2 at lower temperatures than sulfated Pt BaO(20)/Al2O3, a material containing primarily bulk BaO/BaCO3 species. Therefore, after desulfation with H2 up to 1073 K, the amount of the remaining sulfur species on the former, mostly as BaS, is much less than on the latter. This suggests that the initial morphology differences between the two samples play a crucial role in determining the extent of desulfation and the temperature at which it occurs. It is concluded that the removal of sulfur is significantly easier at lower barium loading. This finding can potentially be important in developing more sulfur resistant LNT catalyst systems.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 883679
• Report Number(s): PNNL-SA-47920; 6695; VT0401000; TRN: US200614%%689
• Journal Information: Journal of Physical Chemistry B, 110(21):10441-10448, Vol. 110, Issue 21
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
BARIUM
CATALYSTS
MORPHOLOGY
REMOVAL
SULFATES
PLATINUM
BARIUM OXIDES
DESULFURIZATION
CONCENTRATION RATIO
CATALYTIC EFFECTS
Lean NOx trap
NOx storage
SO2
Sulfur XANES
TR-XRD
TEM
H2 TPRX
Pt BaO/Al2O3
Environmental Molecular Sciences Laboratory