Comparison studies on sintering phenomenon of diesel oxidation catalyst depending upon aging conditions

Kim, Joonwoo; Kim, Chul-Min; Choung, Suk-Jin

doi:10.1016/j.cattod.2011.09.021

Cited by 21 publications

(6 citation statements)

References 11 publications

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“…which increases with the aging effect. This result is in agreement with the literature, since bigger Pt/Pd particles favor NO oxidation[11], Hovewer, when only NO as NOx is present in the feed an opposite trend is observed[12,13]. Moreover for both fresh and aged catalysts, in Mix 1, NO 2 is not detected atFig.…”

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confidence: 93%

Aging of Commercial Diesel Oxidation Catalysts: A preliminary Structure/Reactivity Study

et al. 2016

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This study focuses on the catalytic behavior of the Diesel Oxidation Catalyst using different aging characteristics of road mileage in order to improve the efficiency of an ammonia SCR system on an after-treatment line composed by a DOC + DPF + SCR. The studied catalyst is a commercial diesel oxidation catalyst (Pt/Pd/Al 2 O 3) provided by Continental. Hydrothermal aging were performed on carrots of monolith in varying the temperature of treatment. These carrots were characterized, X-ray diffraction (XRD), transmission electron microscopy (TEM) coupled by EDS and Specific surface measurement (S BET). The catalytic measurements consisted of series of temperature programmed surface reactions (TPSR). To be close to real driving conditions, our experimental setup comprised a pre-heater in which the gases were heated up to 500°C. The goal of this study is to understand the evolution of the active phase with the aging and to correlate these aging results with the corresponding overall catalytic activity and their impact on the reactions involved in the DOC with respect to CO, hydrocarbons and NO.

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confidence: 93%

Aging of Commercial Diesel Oxidation Catalysts: A preliminary Structure/Reactivity Study

et al. 2016

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“…Deconvolution of simultaneous effects is a particularly crucial factor for understanding and improving state-of-the-art catalyst systems. In this respect, even longer aging periods may be considered, as structural changes of the support material typically require either longer aging periods or more severe aging conditions [50,64]. Such investigations will add more facets to the profound knowledge on the aginginduced changes of bimetallic noble metal particles as subject to our study and can help improving catalysts in the future.…”

Section: Discussionmentioning

confidence: 99%

Effects of Hydrothermal Aging on CO and NO Oxidation Activity over Monometallic and Bimetallic Pt-Pd Catalysts

et al. 2021

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By combining scanning transmission electron microscopy, CO chemisorption, and energy dispersive X-ray spectroscopy with CO and NO oxidation light-off measurements we investigated deactivation phenomena of Pt/Al2O3, Pd/Al2O3, and Pt-Pd/Al2O3 model diesel oxidation catalysts during stepwise hydrothermal aging. Aging induces significant particle sintering that results in a decline of the catalytic activity for all catalyst formulations. While the initial aging step caused the most pronounced deactivation and sintering due to Ostwald ripening, the deactivation rates decline during further aging and the catalyst stabilizes at a low level of activity. Most importantly, we observed pronounced morphological changes for the bimetallic catalyst sample: hydrothermal aging at 750 °C causes a stepwise transformation of the Pt-Pd alloy via core-shell structures into inhomogeneous agglomerates of palladium and platinum. Our study shines a light on the aging behavior of noble metal catalysts under industrially relevant conditions and particularly underscores the highly complex transformation of bimetallic Pt-Pd diesel oxidation catalysts during hydrothermal treatment.

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“…In experimental, the same catalyst was hydrothermal treated for different time (1,5,10,20,50, and 100 h). Correspondingly, Kim et al 32 have investigated the sintering phenomenon by various hours under aging conditions, deriving the correlation between the NO activity decay and the BET surface area. However, the studies of active component in different aging time based on the stable support was more meaningful in industrial application, which could be beneficial to understand the loss process of NO oxidation activity.…”

Section: Introductionmentioning

confidence: 99%

Advanced Insight into the Size Effect of PtPd Nanoparticles on NO Oxidation by in Situ FTIR Spectra

Liang

Zhang

et al. 2018

Ind. Eng. Chem. Res.

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It is a recognized view that particle size could play a significant role in catalytic performance. To obtain the nanoparticles with the different size, a series of bimetallic PtPd/SiO 2 −Al 2 O 3 catalysts subjected to hydrothermal treatment in different time were prepared and applied for NO oxidation under diesel exhaust. The experimental results confirmed that the average noble particle size was gradually increased at a different variation rate, along with aging time. An increasing of average particle size resulted in the reduction of the corresponding NO turnover frequencies (TOFs) by different degrees. Thus, a new sight on the relationship between particle size and NO catalytic activity is obtained. In the aging process, the overall trend of noble metal particles got larger along with receding NO catalytic performance, yet in a period, a few small particles presented more bridged/chelating nitrate and ionic nitrate species, further retarding its rate of loss activity.

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Comparison studies on sintering phenomenon of diesel oxidation catalyst depending upon aging conditions

Cited by 21 publications

References 11 publications

Aging of Commercial Diesel Oxidation Catalysts: A preliminary Structure/Reactivity Study

Aging of Commercial Diesel Oxidation Catalysts: A preliminary Structure/Reactivity Study

Effects of Hydrothermal Aging on CO and NO Oxidation Activity over Monometallic and Bimetallic Pt-Pd Catalysts

Advanced Insight into the Size Effect of PtPd Nanoparticles on NO Oxidation by in Situ FTIR Spectra

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