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

Kim, Do Heui; Szanyi, János; Kwak, Ja Hun; Szailer, Tamás; Hanson, Jonathan C.; Wang, Chong Min; Peden, Charles H. F.

doi:10.1021/jp060119f

Cited by 33 publications

(39 citation statements)

References 28 publications

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“…Time-resolved operando synchrotron-based studies (time-resolved x-ray diffraction) and EXAFS and XANES studies (Figure 4.3) clearly showed the mechanism of desulfation and thermal degradation of the fully formulated catalyst. The information obtained from these combined microscopy/spectroscopy/diffraction studies were essential to the successful introduction of this technology by Cummins Inc., in 2007-a remarkable example of detailed, fundamental, operando catalyst characterization leading to the development of a commercial technology (Kim et al 2006;Kwak et al 2009b). Pd on La-stabilized alumina: Recent work on Pd automotive catalysts revealed the unique role of La 2 O 3 .…”

Section: Ba/aluminamentioning

confidence: 99%

Compact X-ray Light Source Workshop Report

Thevuthasan¹,

Evans²,

Terminello³

et al. 2012

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Executive SummaryThis report is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology. The U.S. Department of Energy (DOE) and National Academy of Sciences (NAS) have repeatedly described the need for advanced instruments that "predict, control, and design the components of energetic processes and environmental balance," most notably in biological, chemical, environmental, and materials science. In numerous DOE and NAS reports, direct molecular-scale imaging and timedependent studies are seen as a powerful means to develop an atomistic-level understanding of scientific issues associated with current and future energy and environmental needs, including energy production and storage from both fossil-based and fossil-free sources and cleanup of government and industrial sites worldwide.One of the major enabling capabilities for meeting these needs is a high-brightness x-ray light source. The DOE report, Next-Generation Photon Sources for Grand Challenges in Science and Energy, identifies "spectroscopic and structural imaging of nano-objects (or nanoscale regions of inhomogeneous materials) with nanometer spatial resolution and ultimate spectral resolution" as one of the two aspects of energy science in which current and next-generation x-ray light sources will have the deepest and broadest impact. The report further stresses the power of direct observation in understanding transformational chemical processes. The report also discusses the importance of molecular "movies" of complex reactions that show bond breaking and reforming in natural time scales, along with the intermediate states to understand the mechanisms that govern chemical transformations. Existing accelerator-based x-ray sources have greatly extended capabilities in the time and space domain for scientific investigations in many disciplines. Despite these successes, a number of scientific challenges would benefit greatly from having an x-ray resource that has much of the attractive capability of these large machines but lends itself to operating in conjunction with other characterization tools in a correlative fashion. Such an integrated multiscale and multimodal approach could fully address the fundamental needs expressed by DOE's Office of Biological and Environmental Research (BER) in regards to understanding how genomic information is translated with confidence to redesign microbes, plants, or ecosystems (http://science.energy.gov/).Fortunately, recent advances in laser and super-cooled linear particle accelerator, or linac, technology have enabled development of a long-promised CXLS that uses inverse Compton scattering for generating x-rays. The new CXLS holds the promise of simultaneous energy tuning-from the soft to hard x-ray regime-as well as a pulsed structure closely coupled to the laser pulse duration of pico-to femtoseconds. With a projected brilliance equal to third-generation light sourc...

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Section: Ba/aluminamentioning

confidence: 99%

Compact X-ray Light Source Workshop Report

Thevuthasan¹,

Evans²,

Terminello³

et al. 2012

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“…Sintering of the sulfate during sulfur circulation is controlled in such a form, and this control leads to improvement in sulfur desorption. It has been shown that the decomposition temperature is lowered when the particle size of generated sulfates is smaller [13], and it has also been reported that barium sulfate with a particle size of 3 nm or less is resolved easily at lower temperature [14]. Furthermore, using pore size controlled supports has been found to improve the decomposition of sulfates by physically inhibiting the sintering of the sulfate [30].…”

Section: Catalytic Performancementioning

confidence: 99%

“…Consequently, the deactivation of NSR catalysts depends on the amount of sulfur poisoning of the catalyst [12]. Sulfur deactivation also depends on the particle size of the sulfate produced by the NSR catalyst [13]. It has been reported that the decomposition temperature of sulfates decreases if the BaSO 4 particles in the catalyst are kept under 3 nm in size [14].…”

Section: Introductionmentioning

confidence: 99%

Improvement in sulfur desorption of NOX storage and reduction catalysts using a Ba–Ti composite oxide

Tanaka

Tajima

Kato

et al. 2011

Applied Catalysis B: Environmental

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A Ba-Ti composite oxide was formed on a NOx storage and reduction catalyst via impregnation of a Ba-Ti precursor solution composed of H 2 O 2 added to a complex prepared using the citric acid method. The structure of the Ba-Ti composite in solution was analyzed by chemical composition analysis and FT-Raman and UV-vis spectroscopy. MM2 calculations were performed to propose its chemical structure. Both Ba and Ti together were found to form a composite molecule in the solution.Furthermore, TEM-EDX and XRD analyses of the Ba-Ti composite oxide on the catalyst prepared by impregnation with the Ba-Ti composite aqueous solution revealed that Ba and Ti in the catalyst were highly dispersed at the nm scale. The formation of the Ba-Ti composite oxide on the NSR catalyst enhanced sulfur desorption efficiency and led to high-performance NO X conversion as a NO X storage and reduction activity catalyst after desulfation treatment. It was assumed that the existence of microscopic Ba compounds combined with Ti was efficient for the inhibition of the sintering of barium sulfate and its facile 2 decomposition. It was found that dispersion of Ba compounds for NO X storage materials using a Ba-Ti complex solution is an efficient way to improve the durability of NSR catalysts.

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“…Desulfation of the accumulated SO x involves heating the catalyst to the temperature above 700°C or switching to a reducing atmosphere (CO or H 2 ) [12][13][14][15][16]. The main issue for the high-temperature desulfation is the loss of the catalytic activity caused by thermal aging (precious metal sintering and formation of BaAl 2 O 4 [17]).…”

Section: Introductionmentioning

confidence: 99%

Sulfur Deactivation of NO_xStorage Catalysts: A Multiscale Modeling Approach

Rankovic

Chizallet

Nicolle

et al. 2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Re´sume´-Empoisonnement des mate´riaux de stockage des NO x par le soufre : approche multi-e´chelles -Les pie`ges a`NO x repre´sentent une technologie prometteuse pour la re´duction des e´missions d'oxydes d'azote issus des moteurs ope´rant en me´lange pauvre. Leur utilisation est limite´e par la pre´sence de compose´s soufre´s dans les gaz d'e´chappement. Le soufre contenu dans le carburant et le lubrifiant est oxyde´lors de la combustion en SO 2 et SO 3 . Ces oxydes de soufre pre´sentent une forte affinite´pour le mate´riau de stockage du pie`ge, la formation de sulfate e´tant favorise´e thermodynamiquement. Cette formation contribue au blocage des sites d'adsorption des NO x et influence l'ope´ration de l'organe de post-traitement. La mode´lisation mole´culaire repre´sente un outil pre´cieux pour pre´dire le comportement et les performances du syste`me catalytique. Notre e´tude pre´sente une me´thodologie d'exploitation des calculs ab initio pour la formulation de mode`les cine´tiques de´veloppe´s dans la librairie de post-traitement ve´hicule IFP Exhaust. Nous illustrons notre approche par le cas de l'adsorption de SO 3 sur un mate´riau mode`le, BaO. Afin d'obtenir une description fide`le du mate´riau de stockage re´el, l'adsorption de SO 3 est de´crite sur plusieurs sites : terrasses, marches, crans et le site massique. Des analyses de sensibilite´et de vitesses de re´actions permettent d'obtenir une compre´hension plus approfondie des phe´nome`nes d'empoisonnement mis en jeu.Abstract -Sulfur Deactivation of NO x Storage Catalysts: A Multiscale Modeling ApproachLean NO x Trap (LNT) catalysts, a promising solution for reducing the noxious nitrogen oxide emissions from the lean burn and Diesel engines, are technologically limited by the presence of sulfur in the exhaust gas stream. Sulfur stemming from both fuels and lubricating oils is oxidized during the combustion event and mainly exists as SO x (SO 2 and SO 3 ) in the exhaust. Sulfur oxides interact strongly with the NO x trapping material of a LNT to form thermodynamically favored sulfate species, consequently leading to the blockage of NO x sorption sites and altering the catalyst operation. Molecular and kinetic modeling represent a valuable tool for predicting system behavior and evaluating catalytic performances. The present paper demonstrates how fundamental ab initio calculations can be used as a valuable source for designing kinetic models developed in the IFP Exhaust library, intended for vehicle simulations. The concrete example we chose to illustrate our

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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

Cited by 33 publications

References 28 publications

Compact X-ray Light Source Workshop Report

Compact X-ray Light Source Workshop Report

Improvement in sulfur desorption of NOX storage and reduction catalysts using a Ba–Ti composite oxide

Sulfur Deactivation of NO_xStorage Catalysts: A Multiscale Modeling Approach

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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

Cited by 33 publications

References 28 publications

Compact X-ray Light Source Workshop Report

Compact X-ray Light Source Workshop Report

Improvement in sulfur desorption of NOX storage and reduction catalysts using a Ba–Ti composite oxide

Sulfur Deactivation of NOxStorage Catalysts: A Multiscale Modeling Approach

Contact Info

Product

Resources

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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

Sulfur Deactivation of NO_xStorage Catalysts: A Multiscale Modeling Approach