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Title: Isothermal desulfation of pre-sulfated Pt-BaO/γ-Al2O3 lean NOx trap catalysts with H2: the effect of H2 concentration and the roles of CO2 and H2O

Abstract

The desulfation mechanisms of pre-sulfated Pt-BaO/{gamma}-Al{sub 2}O{sub 3} lean NOx trap catalysts were investigated under isothermal conditions (600 C) using H{sub 2} as the reductant. Sulfates were found to be reduced first with H{sub 2} to produce SO{sub 2}, followed by a reaction between SO{sub 2} and H{sub 2} to produce H{sub 2}S. Gas analysis during the rich pulse reveals that the sulfur removal efficiency is initially proportional to the H{sub 2} concentration. At constant H{sub 2} concentration the overall desulfation efficiency decreases in the order of H{sub 2}/CO{sub 2}/H{sub 2}O > H{sub 2}/CO{sub 2} > H{sub 2}/H{sub 2}O > H{sub 2}, as confirmed by XPS analysis of residual sulfur in the desulfated samples. H{sub 2}O limits the evolution of SO{sub 2} at an early stage of the rich pulse and enhances the production of H{sub 2}S in later stages of reduction. CO{sub 2} is involved in both the formation of COS and the production of H{sub 2}O (via the reverse water-gas shift reaction), therefore, resulting in an increased overall efficiency.

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1032678
Report Number(s):
PNNL-SA-78545
Journal ID: ISSN 0926-3373; ACBEE3; 35404; VT0401000; TRN: US201202%%278
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Applied Catalysis. B, Environmental
Additional Journal Information:
Journal Volume: 111-112; Journal Issue: 1; Journal ID: ISSN 0926-3373
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CATALYSTS; EFFICIENCY; GAS ANALYSIS; PRODUCTION; REMOVAL; SULFATES; SULFUR; WATER GAS; X-RAY PHOTOELECTRON SPECTROSCOPY; Pt-BaO/γ-Al2O3; SO2; lean NOx trap; desulfation; H2S; COS; Environmental Molecular Sciences Laboratory

Citation Formats

Kim, Do Heui, Kwak, Ja Hun, Szanyi, Janos, and Peden, Charles HF. Isothermal desulfation of pre-sulfated Pt-BaO/γ-Al2O3 lean NOx trap catalysts with H2: the effect of H2 concentration and the roles of CO2 and H2O. United States: N. p., 2012. Web. doi:10.1016/j.apcatb.2011.10.017.
Kim, Do Heui, Kwak, Ja Hun, Szanyi, Janos, & Peden, Charles HF. Isothermal desulfation of pre-sulfated Pt-BaO/γ-Al2O3 lean NOx trap catalysts with H2: the effect of H2 concentration and the roles of CO2 and H2O. United States. https://doi.org/10.1016/j.apcatb.2011.10.017
Kim, Do Heui, Kwak, Ja Hun, Szanyi, Janos, and Peden, Charles HF. 2012. "Isothermal desulfation of pre-sulfated Pt-BaO/γ-Al2O3 lean NOx trap catalysts with H2: the effect of H2 concentration and the roles of CO2 and H2O". United States. https://doi.org/10.1016/j.apcatb.2011.10.017.
@article{osti_1032678,
title = {Isothermal desulfation of pre-sulfated Pt-BaO/γ-Al2O3 lean NOx trap catalysts with H2: the effect of H2 concentration and the roles of CO2 and H2O},
author = {Kim, Do Heui and Kwak, Ja Hun and Szanyi, Janos and Peden, Charles HF},
abstractNote = {The desulfation mechanisms of pre-sulfated Pt-BaO/{gamma}-Al{sub 2}O{sub 3} lean NOx trap catalysts were investigated under isothermal conditions (600 C) using H{sub 2} as the reductant. Sulfates were found to be reduced first with H{sub 2} to produce SO{sub 2}, followed by a reaction between SO{sub 2} and H{sub 2} to produce H{sub 2}S. Gas analysis during the rich pulse reveals that the sulfur removal efficiency is initially proportional to the H{sub 2} concentration. At constant H{sub 2} concentration the overall desulfation efficiency decreases in the order of H{sub 2}/CO{sub 2}/H{sub 2}O > H{sub 2}/CO{sub 2} > H{sub 2}/H{sub 2}O > H{sub 2}, as confirmed by XPS analysis of residual sulfur in the desulfated samples. H{sub 2}O limits the evolution of SO{sub 2} at an early stage of the rich pulse and enhances the production of H{sub 2}S in later stages of reduction. CO{sub 2} is involved in both the formation of COS and the production of H{sub 2}O (via the reverse water-gas shift reaction), therefore, resulting in an increased overall efficiency.},
doi = {10.1016/j.apcatb.2011.10.017},
url = {https://www.osti.gov/biblio/1032678}, journal = {Applied Catalysis. B, Environmental},
issn = {0926-3373},
number = 1,
volume = 111-112,
place = {United States},
year = {Thu Jan 12 00:00:00 EST 2012},
month = {Thu Jan 12 00:00:00 EST 2012}
}