Promotional Effects of H2O Treatment on NOx Storage over Fresh and Thermally Aged Pt-BaO/Al2O3 Lean NOx Trap Catalysts

Journal Article · Fri Aug 01 00:00:00 EDT 2008 · Catalysis Letters, 124(1-2):39-45

DOI:https://doi.org/10.1007/s10562-008-9505-6· OSTI ID:949106

Kim, Do Heui; Chin, Ya-Huei; Kwak, Ja Hun; Peden, Charles HF

A simple liquid water treatment applied to fresh and thermally aged Pt(2wt%)-BaO(20wt%)/Al2O3 lean NOx trap catalysts at room temperature induces morphological and structural changes in the barium species as followed by XRD and TEM analysis. During the water treatment, liquid water sufficient to fill the catalyst pore volume is brought into contact with the samples. It was found that irrespective of the original barium chemical state (highly dispersed BaO or crystalline BaAl2O4), exposing the sample to this liquid water treatment promotes the formation of BaCO3 crystallites (about 15 – 25 nm of its size) without changing the Pt particle size. Such transformations of the barium species are found to significantly promote NOx uptake from 250 °C to 450 °C. The increase in the NOx uptake for the water-treated samples can be attributed to an enhanced Pt-Ba interaction through the redistribution of barium species. These results provide useful information for the regeneration of aged lean NOx trap catalysts since water is plentiful in the exhaust of diesel or lean-burn engines.

• 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: 949106
• Report Number(s): PNNL-SA-60403; CALEER; 19800; VT0401000; TRN: US200907%%324
• Journal Information: Catalysis Letters, 124(1-2):39-45, Vol. 124, Issue 1-2; ISSN 1011-372X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
BARIUM OXIDES
PLATINUM
ALUMINIUM OXIDES
CATALYSTS
CHEMICAL STATE
PARTICLE SIZE
REGENERATION
WATER
NITROGEN OXIDES
AIR POLLUTION CONTROL
MORPHOLOGICAL CHANGES
BARIUM CARBONATES
PROMOTERS
SORPTION
Pt-BaO/Al2O3
Lean NOx trap catalyst
water treatment
BaAl2O4
Environmental Molecular Sciences Laboratory