A New Catalyzed HC Trap Technology that Enhances the Conversion of Gasoline Fuel Cold-Start Emissions

Lupescu, Jason; Xu, Lifeng; Jen, Hung-Wen; Harwell, Amy L.; Nunan, John; Alltizer, Chad; Denison, Gregory

doi:10.4271/2018-01-0938

Cited by 19 publications

(4 citation statements)

References 22 publications

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“…Palladium-doped zeolites seem to provide unique advantages over other metals. First, Pd ions are adsorption centers for unsaturated hydrocarbons which expands the trapping capabilities of the zeolite [21]. Additionally, Pd serves as an oxidation catalyst which can oxidize the incoming and trapped hydrocarbons and can impact the desorption properties due to the exotherm generated when hydrocarbons are oxidized [16].…”

Section: Introductionmentioning

confidence: 99%

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Zelinsky

Epling

2021

Catalysts

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Hydrocarbon traps for exhaust emissions control adsorb hydrocarbons in low temperature exhaust and release them as the exhaust warms up. In this work, a Pd/BEA hydrocarbon trap was tested under lean exhaust conditions using ethylene and dodecane as model hydrocarbons. Ethylene uptake was partially inhibited by CO and H2O when fed separately. When both were added, the loss in ethylene uptake was 90% relative to the condition with no H2O or CO. Dodecane uptake was unchanged under all conditions tested. During a temperature ramp, ethylene desorbed and was combusted to CO2 and H2O over active Pd centers. Further, oxidation light-off of dodecane generated an exotherm which caused rapid desorption of the remaining hydrocarbon species from the zeolite. For both hydrocarbons, CO co-feed led to a decreased oxidation light-off temperature, and therefore lower desorption temperature. By pretreating the catalyst in CO and H2O at 80 °C, and even after removing CO from the feed, the enhanced oxidation light-off behavior was observed. DRIFTS characterization shows that some form of oxidized Pd was reducible to Pd0 by CO at 80 °C only in the presence of H2O. Further, this reduction appears reversible by high temperature oxygen treatment. We speculate that this reduced Pd phase serves as the active site for low temperature hydrocarbon oxidation.

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Section: Introductionmentioning

confidence: 99%

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Zelinsky

Epling

2021

Catalysts

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“…This was observed by Lupescu et al as they studied direct-injected gasoline into the exhaust aftertreatment system of a Ford Focus passenger car. They found that the Brønsted acid sites, Pd, and redox-active metals allow the polymerisation of stored HC compounds and that the base redox metal also helps stabilize the Pd from sintering [30].…”

Section: Introductionmentioning

confidence: 99%

Zeolite Beta Doped with La, Fe, and Pd as a Hydrocarbon Trap

et al. 2020

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Hydrocarbon trapping is a technique of great relevance, since a substantial part of hydrocarbon emissions from engines are released from engines before the catalyst has reached the temperature for efficient conversion of the hydrocarbons. In this work, the influence of doping zeolite beta (BEA) with Fe, Pd, and La on the storage and release of propene and toluene is studied. Five monolith samples were prepared; Fe/BEA, La/BEA, Pd/BEA, Pd/Fe/BEA, and Pd/La/BEA using incipient wetness impregnation, and the corresponding powder samples were used for catalyst characterization by Inductively coupled plasma sector field mass spectrometry (ICP-SFMS), Temperature-programmed oxidation (TPO), X-ray photoelectron spectroscopy (XPS) and Scanning transmission electron microscopy with Energy dispersive X-ray analysis (STEM-EDX). The hydrocarbon trapping ability of the samples was quantified using Temperature-programmed desorption (TPD) of propene and toluene, and in situ Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results from the TPD experiments show that the addition of Pd and La to the zeolite affected the release patterns of the stored hydrocarbons on the trapping material in a positive way. The in situ DRIFTS results indicate that these elements provide H-BEA with additional sites for the storage of hydrocarbons. Furthermore, EDX-mapping showed that the La and Pd are located in close connection.

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“…[3][4][5][6] Both have been proven to have low NO x reduction efficiency when the exhaust temperature is lower than 200 °C. [7][8][9][10] Furthermore, the emissions from the coldstart period make up a large proportion of the total NO x emissions during a drive cycle, which cannot be removed effectively by SCR or NSR technologies. 11 What is more, in future, emission regulations will be stringent enough to have to deal with low-temperature exhausts.…”

Section: Introductionmentioning

confidence: 99%

Ultra-stable Pd ions at Al T1/T2 sites on a dealuminated Pd/beta passive NO_xadsorber

Zhu,

Wang,

Wang

et al. 2023

Catal. Sci. Technol.

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A New Catalyzed HC Trap Technology that Enhances the Conversion of Gasoline Fuel Cold-Start Emissions

Cited by 19 publications

References 22 publications

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Zeolite Beta Doped with La, Fe, and Pd as a Hydrocarbon Trap

Ultra-stable Pd ions at Al T1/T2 sites on a dealuminated Pd/beta passive NO_xadsorber

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A New Catalyzed HC Trap Technology that Enhances the Conversion of Gasoline Fuel Cold-Start Emissions

Cited by 19 publications

References 22 publications

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Zeolite Beta Doped with La, Fe, and Pd as a Hydrocarbon Trap

Ultra-stable Pd ions at Al T1/T2 sites on a dealuminated Pd/beta passive NOxadsorber

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About

Ultra-stable Pd ions at Al T1/T2 sites on a dealuminated Pd/beta passive NO_xadsorber