Evolution of unburnt hydrocarbons under “cold-start” conditions from adsorption/desorption to conversion: On the screening of zeolitic materials

Westermann, Alexandre; Azambre, B.; Finqueneisel, G.; Costa, Patrick Da; Can, Fabien

doi:10.1016/j.apcatb.2014.04.005

Cited by 50 publications

(36 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This indicates that the desorption of propene in this temperature range can be associated with desorption from the zeolite BEA, i.e., the Brønstedt acid sites [5,17]. The high storage capacity of propene in Figure 4 can be explained by the low SiO 2 /Al 2 O 3 ratio of the zeolite used in the present study, which is consistent with previous studies [17,18,25]. Furthermore, the XPS results (see Figure 2) show that the oxidation state of Pd becomes lower when introducing Fe and especially La.…”

Section: Temperature-programmed Desorption Of Hydrocarbonssupporting

confidence: 92%

“…These results contradict the results from the propene-TPD experiments, where the addition of Pd resulted in lower storage capacity of propene in dry conditions. We suggest that the reason for this difference is that the phenyl ring of toluene can also adsorb Lewis acid sites [10][11][12][18][19][20], such as Pd, while propene preferentially interacts with Brønsted acid sites through hydrogen bonding with the π electrons in the C=C bond [17]. Some desorption peaks also appear at higher temperatures in Figure 5.…”

Section: Beamentioning

confidence: 96%

“…Toluene; however, is proposed to interact with both the Brønsted and Lewis acid sites. Negatively charged oxygen in the zeolite structure interacts with the methyl group in toluene, while the Lewis and Brønsted acid sites interact with the phenyl ring [10][11][12][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2020

View full text Add to dashboard Cite

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.

show abstract

Section: Temperature-programmed Desorption Of Hydrocarbonssupporting

confidence: 92%

Section: Beamentioning

confidence: 96%

See 1 more Smart Citation

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

et al. 2020

View full text Add to dashboard Cite

show abstract

“…M a n u s c r i p t 9 The thermal behavior of the catalyst was studied in a Metter Toledo TGA/SDTA 851 instrument. The weight changes of the catalyst (≈15 mg of the samples) were analyzed from 25 to 900 ºC with a heating rate of 10 ºC.…”

Section: Thermal Gravimetric Analysismentioning

confidence: 99%

“…It has long been recognized that the key to reduce hydrocarbon emissions is to rapidly increase the temperature of the modern three-way catalysts when the vehicle is first started [6]. In this sense, the majority of HC emissions (up to 80 %) occur A c c e p t e d M a n u s c r i p t 5 during the cold-start period where any unburned HC is simply released from the tailpipe to the atmosphere [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Hydrocarbon adsorption and NOx-SCR on (Cs,Co)mordenite

Serra

Aspromonte

Miró

et al. 2015

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

Effect of temperature Ramp on hydrocarbon desorption profiles from zeolite ZSM‐12

et al. 2016

View full text Add to dashboard Cite

Zeolite ZSM-12 with different Si:Al molar ratios and one-dimensional channels with 12 oxygen ring apertures (12R) was synthesized and characterized by different techniques such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area (BET), elemental analysis by atomic absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) of adsorbed pyridine, and NH 3 temperature-programmed desorption (TPD). The synthesized samples were tested as hydrocarbon (HC) trap adsorbents using toluene and ethylene as heavy and light probe molecules for HCs in the exhaust stream at engine cold-start. High heating rate desorption experiments were performed using the Phytronix Laser Diode Thermal Desorption system (S-960 LDTD) coupled with an Atmospheric Pressure Chemical Ionization (APCI) chamber (Phytronix Technologies, Canada) after adsorption of toluene-ethylene mixtures. Three heating rates, which reflect the actual heating rates of the catalytic muffler, were used for the desorption process: 3 8C/s, 5 8C/s, and 9 8C/s. For all solids considered in this study, the two HCs desorbed above 240 8C, which is the light-off temperature of the three-way catalyst. Ag-ZSM-12 with different Si:Al ratios was found the most appropriate HC trapping adsorbent in spite of its slightly lower adsorption capacity. A high desorption temperature for ethylene and toluene was associated with the large density of strong Lewis acid sites in this solid.

show abstract

Evolution of unburnt hydrocarbons under “cold-start” conditions from adsorption/desorption to conversion: On the screening of zeolitic materials

Cited by 50 publications

References 37 publications

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

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

Hydrocarbon adsorption and NOx-SCR on (Cs,Co)mordenite

Effect of temperature Ramp on hydrocarbon desorption profiles from zeolite ZSM‐12

Contact Info

Product

Resources

About