Scaling Relations and Kinetic Monte Carlo Simulations To Bridge the Materials Gap in Heterogeneous Catalysis

Jørgensen, Mikkel; Grönbeck, Henrik

doi:10.1021/acscatal.7b01194

“…Ther eaction is strongly influenced by complex kinetic couplings between sites,a nd am ultitude of sites leads to ahigh TOF. Thus,taking the site-assembly into account is key in understanding catalytic reactions over nanoparticles.CO oxidation over Pt is modeled using the following reaction Scheme:TheM onte Carlo simulations are carried out using the recently introduced scaling relation Monte Carlo (SRMC) method [21] (See also the Supporting Information). In SRMC, the adsorption energies and energy barriers on each site are treated using scaling relations in the generalized coordination numbers [14,15] (CN).…”

mentioning

confidence: 99%

The Site‐Assembly Determines Catalytic Activity of Nanoparticles

Jørgensen

¹

,

Grönbeck

²

2018

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Heterogeneous catalysts are often designed as metal nanoparticles supported on oxide surfaces. Here, the relation between particle morphology and reaction kinetics is investigated by scaling relation kinetic Monte Carlo simulations using CO oxidation over Pt nanoparticles as a model reaction. We find that different particle morphologies result in vastly different catalytic activities. The activity is strongly affected by kinetic couplings between sites, and a wide site distribution generally enhances the activity. The present study highlights the role of site-assemblies as a concept that, in addition to isolated active sites, can be used to understand catalytic reactions over nanoparticles.

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“…[17,21] We note that CO oxidation is an exothermic reaction. In addition to the size dependence,the reaction conditions influence the most active geometry,a sthea ctive site changes with reaction conditions.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[4][5][6][7] Theoretically, density functional theory [8,9] (DFT) calculations have outlined how adsorption properties depend on particle geometry, [10,11] which has been rationalized by descriptors such as coordination numbers and d-band centers. Thus,taking the site-assembly into account is key in understanding catalytic reactions over nanoparticles.CO oxidation over Pt is modeled using the following reaction Scheme:TheM onte Carlo simulations are carried out using the recently introduced scaling relation Monte Carlo (SRMC) method [21] (See also the Supporting Information). [13,16] However,t reating sites as isolated entities implies that kinetic couplings between the sites are neglected.…”

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confidence: 99%

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The Site‐Assembly Determines Catalytic Activity of Nanoparticles

Jørgensen

¹

,

Grönbeck

²

2018

Self Cite

View full text Add to dashboard Cite

Heterogeneous catalysts are often designed as metal nanoparticles supported on oxide surfaces.H ere,t he relation between particle morphology and reaction kinetics is investigated by scaling relation kinetic Monte Carlo simulations using CO oxidation over Pt nanoparticles as amodel reaction. We find that different particle morphologies result in vastly different catalytic activities.The activity is strongly affected by kinetic couplings between sites,a nd aw ide site distribution generally enhances the activity.The present study highlights the role of site-assemblies as aconcept that, in addition to isolated active sites,c an be used to understand catalytic reactions over nanoparticles.Heterogeneous catalysts are commonly realized as metal nanoparticles supported on oxide-surfaces.The nanoparticles in technical catalysts are generally ill-defined with respect to shape and size,a nd the contribution of different particle geometries and sizes to the measured catalytic activity is difficult to disentangle.T he situation can be further complicated by changes in particle shape arising in response to the reaction conditions. [1-3] As particle shape may affect catalytic activity,itbecomes important to understand the link between particle morphology and catalyst performance.T his topic, although central, has not received much systematic attention. Experimental studies of multiple reactions have revealed size and shape dependencies of the activity. [4][5][6][7] Theoretically, density functional theory [8,9] (DFT) calculations have outlined how adsorption properties depend on particle geometry, [10,11] which has been rationalized by descriptors such as coordination numbers and d-band centers. [12][13][14][15] Structure sensitivity in the catalytic activity has generally been investigated by dividing the catalyst into isolated facets with one type of site. [13,16] However,t reating sites as isolated entities implies that kinetic couplings between the sites are neglected. CO oxidation is ap rototypical model reaction, for which microkinetic models have predicted reactivity and size dependence for different metal particles. [17,18] However,these models were formulated in the mean field approximation (MFA), which does not account for the specific arrangement and detailed kinetic couplings of sites.T he importance of as ite distribution, or site-assembly,h ave previously been recognized as complex kinetic couplings,b oth experimentally [19] and by schematic kinetic Monte Carlo simulations. [20] These studies indicate that the site-assembly can be crucial for the reaction kinetics,h owever without quantitative estimates.T hus there is agap in the understanding of the relation between particle morphology and catalytic activity.Thepresent article explores the relation between particle geometry and catalytic activity,b yp resenting first-principles kinetic Monte Carlo simulations over nanoparticles of different shapes,u sing CO oxidation over Pt nanoparticles as an archetype reaction. We find that identical sites on different geome...

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“…Recently, the atop GCN has been adopted to estimate current densities and mass activities of electro-catalysts, for oxygen reduction, [15] CO 2 reduction, [22] and CO oxygenation. [23,24] For the case of Oxygen Reduction Reaction, experiments and theoretical calculations demonstrated that the strength of the interaction with OH decreases for increasingly generalisedcoordinated sites. In turn the outcome of a coordination-activity analysis displays a characteristic volcano-shape with sites with GCN = 8.33 at its top.…”

Section: Characterisation Of Pt-nps Architectures and Active Sitesmentioning

confidence: 99%

Correlating Oxygen Reduction Reaction Activity and Structural Rearrangements in MgO‐Supported Platinum Nanoparticles

Rossi

¹

,

Asara

²

,

Baletto

³

2019

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We develop a multi‐scale approach towards the design of metallic nanoparticles with applications as catalysts in electrochemical reactions. The here discussed method exploits the relationship between nanoparticle architecture and electrochemical activity and is applied to study the catalytic properties of MgO(100)‐supported Pt nanosystems undergoing solid‐solid and solid‐liquid transitions. We observe that a major increment in the activity is associated to the reconstruction of the interface layers, supporting the need for a full geometrical characterisation of such structures also when in‐operando.

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Scaling Relations and Kinetic Monte Carlo Simulations To Bridge the Materials Gap in Heterogeneous Catalysis

Cited by 85 publications

References 58 publications

The Site‐Assembly Determines Catalytic Activity of Nanoparticles

The Site‐Assembly Determines Catalytic Activity of Nanoparticles

The Site‐Assembly Determines Catalytic Activity of Nanoparticles

Correlating Oxygen Reduction Reaction Activity and Structural Rearrangements in MgO‐Supported Platinum Nanoparticles

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