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

Journal Article · Thu Jan 12 04:00:00 EST 2012 · Applied Catalysis. B, Environmental

DOI:https://doi.org/10.1016/j.apcatb.2011.10.017· OSTI ID:1032678

Kim, Do Heui; Kwak, Ja Hun; Szanyi, Janos; Peden, Charles HF

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.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1032678
• Report Number(s): PNNL-SA-78545; 35404; VT0401000
• Journal Information: Applied Catalysis. B, Environmental, Journal Name: Applied Catalysis. B, Environmental Journal Issue: 1 Vol. 111-112; ISSN 0926-3373; ISSN ACBEE3
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CATALYSTS
COS
EFFICIENCY
Environmental Molecular Sciences Laboratory
GAS ANALYSIS
H2S
PRODUCTION
Pt-BaO/γ-Al2O3
REMOVAL
SO2
SULFATES
SULFUR
WATER GAS
X-RAY PHOTOELECTRON SPECTROSCOPY
desulfation
lean NOx trap