The Effect of Phosphorus Exposure on Diesel Oxidation Catalysts—Part II: Characterization of Structural Changes by Transmission Electron Microscopy

Honkanen, Mari; Kärkkäinen, Mikko; Heikkinen, Olli; Kallinen, Kauko; Kolli, Tanja; Huuhtanen, Mika; Lahtinen, Jouko; Keiski, Riitta L.; Lepistö, Toivo; Vippola, Minnamari

doi:10.1007/s11244-015-0465-y

Cited by 11 publications

(12 citation statements)

References 11 publications

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“…Such changes in platinum particle morphology may, in turn, affect catalyst activity, as they may affect the distribution of catalyst particle surface planes available for reactants to interact with. Similar changes in precious metal particle morphology have also been observed by Honkanen et al [19] after thermal aging performed during the flow-through of a gas phase containing a vaporized solution of a phosphorus salt. Their results showed a change in morphology towards more spherical precious metal particles after such aging compared to what was observed after similar thermal aging without the presence of phosphorus.…”

Section: Resultssupporting

confidence: 80%

Assessment of the Impact of Trace Elements in FAME Biodiesel on Diesel Oxidation Catalyst Activity after Full Lifetime of Operation in A Heavy-Duty Truck

et al. 2020

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Fatty acid methyl ester (FAME) biodiesel contains some trace amounts of Na, K, P, Ca, and Mg. Our objective was to investigate whether the presence of such elements can poison a diesel oxidation catalyst that has been used for an entire regulatory lifetime in a heavy-duty truck fueled by FAME biodiesel. The investigated vehicle-aged catalyst contained high loadings of S, P, and Na, as well as a visible layer of soot. Activity in the NO oxidation reaction was severely decreased compared to a fresh catalyst of the same type, while the CO and C3H6 oxidation reactions were less affected. Subsequent selective trace element removal procedures, followed by activity tests, were used to decouple the effect of different poisons. Sintering was observed to be the main cause of catalyst deactivation. Of the trace elements present on the catalyst, P had the greatest effect on catalyst activity, while the other trace elements had little effect.

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Section: Resultssupporting

confidence: 80%

Assessment of the Impact of Trace Elements in FAME Biodiesel on Diesel Oxidation Catalyst Activity after Full Lifetime of Operation in A Heavy-Duty Truck

et al. 2020

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“…In addition, carbon (soot) and phosphorus were detected regularly ( Figure 4b and c). Phosphorus exposure is known to cause such growth and shape effects in the noble metals [11,12]. The cross-sectional TEM images from the fresh and vehicle-aged diesel oxidation catalysts are presented in Figure 5.…”

Section: Electron Microscopymentioning

confidence: 99%

“…For example, biodiesel, ethanol and natural gas are challenging the traditional fuels in transportation use for the future. Although there have been advances in the lowering of emissions of these more efficient combustion processes, the deactivation and ageing problems of the catalysts remain at a certain level [1][2][3][4][5][6][7][8][9][10][11][12]. To meet the demands for more efficient and clean engines, there is a great need to study deactivation and ageing effects of these different types of fuels with catalytic materials and other phenomena.…”

Section: Introductionmentioning

confidence: 99%

“…Thermal ageing due to high temperature conditions in the vehicle engine can cause loss of the active surface via, for example, sintering and phase transformations. In heavy-duty vehicle engines, the roles and characteristics of these problems are still quite seldom addressed in comparison to studies from smaller vehicles and/or gasoline-fueled cars [7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Microstructural Characteristics of Vehicle-Aged Heavy-Duty Diesel Oxidation Catalyst and Natural Gas Three-Way Catalyst

et al. 2019

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Techniques to control vehicle engine emissions have been under increasing need for development during the last few years in the more and more strictly regulated society. In this study, vehicle-aged heavy-duty catalysts from diesel and natural gas engines were analyzed using a cross-sectional electron microscopy method with both a scanning electron microscope and a transmission electron microscope. Also, additional supporting characterization methods including X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and catalytic performance analyses were used to reveal the ageing effects. Structural and elemental investigations were performed on these samples, and the effect of real-life ageing of the catalyst was studied in comparison with fresh catalyst samples. In the real-life use of two different catalysts, the poison penetration varied greatly depending on the engine and fuel at hand: the diesel oxidation catalyst appeared to suffer more thorough changes than the natural gas catalyst, which was affected only in the inlet part of the catalyst. The most common poison, sulphur, in the diesel oxidation catalyst was connected to cerium-rich areas. On the other hand, the severities of the ageing effects were more pronounced in the natural gas catalyst, with heavy structural changes in the washcoat and high concentrations of poisons, mainly zinc, phosphorus and silicon, on the surface of the inlet part.

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“…It is well known that phosphorus besides the other known catalyst poisons has a significant effect on the activity and the durability of the catalytic converter. The effect of phosphorus on noble metal based catalysts such as Pd/Al 2 O 3 (NGO) in lean burn [11] and stoichiometric [17] conditions and PtPd/Al 2 O 3 (diesel oxidation catalyst, DOC) [18][19][20][21] has been investigated.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Phosphorus Exposure on a Natural-Gas-Oxidation Catalyst

et al. 2016

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Phosphorus is found to have a deactivating effect on the catalytic activity of the studied natural-gas-oxidation catalyst. Accelerated laboratory-scale phosphorus treatment was done to the PtPd/Al 2 O 3 natural gas oxidation catalyst. The effect of phosphorus after low (0.065 M) and high (0.13 M) phosphorus concentration treatments was studied by using an inductively coupled plasma optical emission spectroscopy, N 2 physisorption, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. In addition, the behavior of the catalyst was studied by a Gasmet FT-IR gas analyzer. Based on the received results it can be concluded that phosphorus was adsorbed on the surface by chemical bonds forming phosphates (PO 4 ). In addition, the partial transformation of PdO to Pd was observed. Due to the phosphorus adsorption both the CO and CH 4 oxidation activities were lower after the phosphorus treatments compared with the fresh catalyst.

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The Effect of Phosphorus Exposure on Diesel Oxidation Catalysts—Part II: Characterization of Structural Changes by Transmission Electron Microscopy

Cited by 11 publications

References 11 publications

Assessment of the Impact of Trace Elements in FAME Biodiesel on Diesel Oxidation Catalyst Activity after Full Lifetime of Operation in A Heavy-Duty Truck

Assessment of the Impact of Trace Elements in FAME Biodiesel on Diesel Oxidation Catalyst Activity after Full Lifetime of Operation in A Heavy-Duty Truck

Microstructural Characteristics of Vehicle-Aged Heavy-Duty Diesel Oxidation Catalyst and Natural Gas Three-Way Catalyst

The Influence of Phosphorus Exposure on a Natural-Gas-Oxidation Catalyst

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