Monolith and TAP reactor studies of NOX storage on Pt/BaO/Al2O3: Elucidating the mechanistic pathways and roles of Pt

Kabin, Karen S.; Khanna, Pranav; Muncrief, Rachel; Medhekar, Vinay; Harold, Michael P.

doi:10.1016/j.cattod.2006.02.004

Cited by 82 publications

(48 citation statements)

References 38 publications

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“…The TAP technique has been applied to different reaction systems involving heterogeneous catalysis: Reaction transport (adsorption and diffusion) [44,45]; reforming of hydrocarbons [46][47][48][49][50][51]; hydrogenation and dehydrogenation reactions [52,53]; environmental catalysis [54][55][56][57][58]; oxidation reactions etc. [59][60][61][62][63][64][65][66][67].…”

Section: Approaches Of Kinetic Analysis For Ftsmentioning

confidence: 99%

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

Yang

Chen

et al. 2014

Catal Lett

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During the last years it has been an increasing focus on fundamental studies of the Fischer-Tropsch synthesis (FTS). Steady-state isotopic transient kinetic analysis and first principles investigation have proven to be important methods in studying the reaction mechanism of FTS. The present contribution deals with recent progresses in understanding of the F-T mechanism on Co catalysts based on combined DFT calculations, in situ characterization, steady-state isotopic transient kinetic analysis and microkinetics. A brief outlook into future perspectives of the FTS for converting synthesis gas from different carbon sources to fuels and chemicals is also provided.

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Section: Approaches Of Kinetic Analysis For Ftsmentioning

confidence: 99%

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

Yang

Chen

et al. 2014

Catal Lett

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“…This approach appears to be in sharp contrast with that of Lindholm et al [17], which allows the direct deposition of NO on both carbonate and so-called S 3 sites. Kabin et al [45] argued for the importance of the spillover reaction (S33) and suggested that the formation of BaO-O was followed by the attachment of gas-phase NO and/or NO 2 , as in (9) and (10) above.…”

Section: Resultsmentioning

confidence: 99%

Microkinetic Modeling of Lean NO<sub>x</sub> Trap Storage and Regeneration

Larson

Chakravarthy

Pihl

et al. 2011

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A microkinetic chemical reaction mechanism capable of describing both the storage and regeneration processes in a fully formulated lean NO x trap (LNT) is presented. The mechanism includes steps occurring on the precious metal, barium oxide (NO x storage), and cerium oxide (oxygen storage) sites of the catalyst. The complete reaction set is used in conjunction with a transient plug flow reactor code (including boundary layer mass transfer) to simulate not only a set of long storage/regeneration cycles with a CO/H 2 reductant, but also a series of steady flow temperature sweep experiments that were previously analyzed with just a precious metal mechanism and a steady state code neglecting mass transfer. The results show that, while mass transfer effects are generally minor, NO x storage is not negligible during some of the temperature ramps, necessitating a re-evaluation of the precious metal kinetic parameters. The parameters for the entire mechanism are inferred by finding the best overall fit to the complete set of experiments. Rigorous thermodynamic consistency is enforced for parallel reaction pathways and with respect to known data for all of the gas phase species involved. It is found that, with a few minor exceptions, all of the basic experimental observations can be reproduced with the transient simulations. In addition to accounting for normal cycling behavior, the final mechanism should provide a starting point for the description of further LNT phenomena such as desulfation and the role of alternative reductants. 4 ACKNOWLEDGMENTSThe authors thank Dr. Andrew Lutz, formerly of Sandia, for initial development of the Chemkinbased transient plug flow reactor code (TPLUG).

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“…126 NO pulse experiments revealed a mechanism that combined both NO decomposition and storage. 126 This mechanism infers a spillover of oxygen adatoms from the Pt to the Ba phase, producing BaO 2 which is then involved in NO storage via barium nitrate.…”

Section: Studies With Monolithsmentioning

confidence: 99%

“…While powdered catalysts have been the most commonly studied using TAP, the same methodologies have also been employed to characterize monolith catalysts for diffusivity 60,126 as well as mechanistic and kinetic studies. For instance, the transient catalytic process of NOx storage and reduction on monolith washcoated with Pt/Al 2 O 3 and Pt/Ba/ Al 2 O 3 have been studied (which were compared to analogous powdered catalysts) with the reactor configurations reported in Fig.…”

Section: Studies With Monolithsmentioning

confidence: 99%

“…108,126,127 A range of multi-pulse and consecutive pulse (pump-probe) studies were applied in order to assess NO storage capacity, 115,126 and mechanistic insight into the storage and reduction processes. 108,126,127 Importantly, similar results were reported for the powdered catalysts and the monoliths. 126 NO pulse experiments revealed a mechanism that combined both NO decomposition and storage.…”

Section: Studies With Monolithsmentioning

confidence: 99%

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Forty years of temporal analysis of products

Morgan

Maguire

Fushimi

et al. 2017

Catal. Sci. Technol.

127

101

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A detailed understanding of reaction mechanisms and kinetics is required in order to develop and optimize catalysts and catalytic processes. While steady-state investigations are known to give a global view of the catalytic system, transient studies are invaluable since they can provide more comprehensive insight into elementary steps. For almost forty years temporal analysis of products (TAP) has been successfully utilized for transient studies of gas phase heterogeneous reactions, and there have been a number of advances in instrumentation and numerical modeling methods in that time. Since TAP is a complex methodology it is often viewed as a niche specialty. With the purpose to make TAP more relevant and approachable to a wider segment of the catalytic research community, part of the intention of this work is to highlight the significant contributions TAP has made to elucidating mechanistic and kinetic aspects of complex, multistep heterogeneous reactions. With this in mind, an outlook is also disclosed for the technique in terms of what is needed to revitalize the field and make it more applicable to the recent advances in catalyst characterization (e.g. operando modes).

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Monolith and TAP reactor studies of NOX storage on Pt/BaO/Al2O3: Elucidating the mechanistic pathways and roles of Pt

Cited by 82 publications

References 38 publications

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

Microkinetic Modeling of Lean NO<sub>x</sub> Trap Storage and Regeneration

Forty years of temporal analysis of products

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