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Title: 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

Abstract

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.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
883679
Report Number(s):
PNNL-SA-47920
6695; VT0401000; TRN: US200614%%689
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B, 110(21):10441-10448
Additional Journal Information:
Journal Volume: 110; Journal Issue: 21
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Kim, Do Heui, Szanyi, Janos, Kwak, Ja Hun, Szailer, Tamas, Hanson, Jonathan, Wang, Chong M, and Peden, Charles HF. 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. United States: N. p., 2006. Web.
Kim, Do Heui, Szanyi, Janos, Kwak, Ja Hun, Szailer, Tamas, Hanson, Jonathan, Wang, Chong M, & Peden, Charles HF. 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. United States.
Kim, Do Heui, Szanyi, Janos, Kwak, Ja Hun, Szailer, Tamas, Hanson, Jonathan, Wang, Chong M, and Peden, Charles HF. Thu . "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". United States.
@article{osti_883679,
title = {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},
author = {Kim, Do Heui and Szanyi, Janos and Kwak, Ja Hun and Szailer, Tamas and Hanson, Jonathan and Wang, Chong M and Peden, Charles HF},
abstractNote = {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.},
doi = {},
journal = {Journal of Physical Chemistry B, 110(21):10441-10448},
number = 21,
volume = 110,
place = {United States},
year = {2006},
month = {6}
}