The impact of CO and C3H6 pulses on PtO  reduction and NO oxidation in a diesel oxidation catalyst

Arvajová, Adéla Buzková; Kočí, Petr; Schmeißer, Volker; Weibel, Michel

doi:10.1016/j.apcatb.2015.08.004

Cited by 34 publications

(11 citation statements)

References 18 publications

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“…The presented operando XANES data demonstrate that in the case of highly dispersed Pt particles the stabilization of PtO x species on the platinum surface takes place in the whole temperature range of interest up to 400 °C (Figure ). Similar behavior was established during mathematical simulations of Pt‐based diesel oxidation catalysts under lean conditions . The surface coverage of PtO x was found to vary from 0.3 to 0.8 depending on the reaction temperature.…”

Section: Discussionsupporting

confidence: 70%

“…It was claimed that deactivation of Pt/Al 2 O 3 in the catalytic NH 3 oxidation occurs at temperatures below 130°C due to the accumulation of NH x species on the Pt surface while adsorbed oxygen species cause deactivation at higher temperatures. [57,66] The surface coverage of PtO x was found to vary from 0.3 to 0.8 depending on the reaction temperature. Similar behavior was established during mathematical simulations of Pt-based diesel oxidation catalysts under lean conditions.…”

Section: Discussionmentioning

confidence: 99%

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Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

et al. 2019

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Two series of Pt/γ-Al 2 O 3 catalysts for low temperature NH 3 oxidation were prepared using Pt(NO 3 ) 4 and H 2 PtCl 6 precursors. Using both precursors results in the formation of small Pt particles (d < 1.5 nm), however, Cl-containing Pt precursors give a higher fraction of highly dispersed Pt species. Such species show high stability against thermal or H 2 treatment probably due to the presence of a substantial amount of chlorine on the surface. Treatment of the samples prepared from Pt(NO 3 ) 4 with H 2 leads to the formation of metallic Pt nanoparticles accompanied by the improvement of catalytic activity in NH 3 oxidation at T < 200°C. The main products of ammonia oxidation at temperatures below 250°C were molecular nitrogen and nitrous oxide with the N 2 selectivity reaching 80 %. Operando XANES/ EXAFS revealed that even after H 2 pretreatment at least 40 % of Pt surface remains in oxidized state under reaction conditions resulting in the appearance of N 2 O as a by-product.

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Section: Discussionsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 99%

Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

et al. 2019

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“…Similarly, reaction 10 denotes noble metal reduction at low temperatures by NO and oxidation in the presence of NO 2 at higher temperatures. Arvajová et al also investigated the reactivation of a Pt-based catalyst and considered a pragmatic global approach similar to reaction 7 which was adapted here [21].…”

Section: Catalyst Oxidation and Reduction Ratesmentioning

confidence: 74%

“…Arvajová et al. also investigated the reactivation of a Pt‐based catalyst and considered a pragmatic global approach similar to reaction 7 which was adapted here .…”

Section: Global Kinetic Modelingmentioning

confidence: 99%

Modeling of Conversion Hysteresis Phenomena for Pt/Pd‐based Diesel Oxidation Catalysts

Dubbe

Eigenberger

Nieken

2018

Chemie Ingenieur Technik

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Recent findings in the conversion behavior of diesel oxidation catalysts (DOCs) show a strong dependence between performance and oxidation state of the catalyst. Furthermore, a slow and reversible change of catalyst oxidation state has been observed under cyclic temperature changes with realistic exhaust gas conditions, which can result in a significant inverse hysteresis during light‐off and subsequent light‐out. In this contribution, an existing 1D global kinetic model for Pt‐only DOCs is developed further, considering CO and hydrocarbon interaction. It is also applied to a Pd‐only and PtPd‐alloyed catalyst.

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“…The practical relevance of such reversible activation/ deactivation effects for the adjustment of an optimal NO/ NO 2 ratio has been highlighted by Bandl-Konrad et al [10] and Arvajová et al [11]. They showed that a reducing CO and C 3 H 6 pulse can restore the activity of deactivated PtO X while keeping lean conditions.…”

Section: Introductionmentioning

confidence: 95%

HC-Induced Deactivation in CO Conversion at Diesel Oxidation Catalysts

Herrmann

Malmberg

Drochner

et al. 2016

Emiss. Control Sci. Technol.

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This paper examines the activity of a platinum catalyst for the oxidation of CO under conditions of temperature cycling. Each cycle consists of an ignition and extinction curve obtained with a linear temperature ramp. It is shown that the catalyst activity is higher for the first ignition cycle than for the subsequent ones regarding CO conversion. The activity for the extinction portion of each cycle is the same for all cycles. It is proposed that the loss of catalyst activity results from the deposition of hydrocarbon residues during the extinction part of the cycle. The catalyst activity can be completely restored by heating the catalyst to 350°C in the presence of oxygen and nitrogen.

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The impact of CO and C3H6 pulses on PtO reduction and NO oxidation in a diesel oxidation catalyst

Cited by 34 publications

References 18 publications

Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

Modeling of Conversion Hysteresis Phenomena for Pt/Pd‐based Diesel Oxidation Catalysts

HC-Induced Deactivation in CO Conversion at Diesel Oxidation Catalysts

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The impact of CO and C3H6 pulses on PtO reduction and NO oxidation in a diesel oxidation catalyst

Cited by 34 publications

References 18 publications

Insight into the Nature of Active Species of Pt/Al2O3 Catalysts for low Temperature NH3 Oxidation

Insight into the Nature of Active Species of Pt/Al2O3 Catalysts for low Temperature NH3 Oxidation

Modeling of Conversion Hysteresis Phenomena for Pt/Pd‐based Diesel Oxidation Catalysts

HC-Induced Deactivation in CO Conversion at Diesel Oxidation Catalysts

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Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation