Theoretical Investigation of Metal‐Support Interactions on Ripening Kinetics of Supported Particles

Hu, Sulei; Li, Wei‐Xue

doi:10.1002/cnma.201800052

Cited by 17 publications

(45 citation statements)

References 74 publications

(37 reference statements)

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“…At ypical result startingf rom 200 Kw ithaheating rate of 1Ks À1 is plotted in Figure 3a.W hen T is lower than 900 K, there is nearly nothingc hange in PSD shape as well as N, D and < d > .T his can be rationalized by large total activation energy of 3eVu sed in present work, and influence of total activation energy on ripeningk inetics can be found in our recent work. [16] When temperature is heated up to 935 K, there is about 11 %d ecrease of the peak height and 0.26 right shift of peak position ( Figure 3b). After this, the ripening proceeds faster.T he resultingP SD remainsL SW-like, same with isothermal condition.…”

Section: Resultsmentioning

confidence: 95%

“…[16,17] To describe the overall behavior of the ripeningr esistance and quantify their relative contributions, it is important to describe all of them consistentlyi no ne framework and corresponding work is ongoing. [16,17] To describe the overall behavior of the ripeningr esistance and quantify their relative contributions, it is important to describe all of them consistentlyi no ne framework and corresponding work is ongoing.…”

Section: Half-lifetime and Onset Temperature Of Ripeningmentioning

confidence: 99%

“…We note that the presentw ork focuseso nt he influence of PSD on ripening kinetics only.I na ddition, the metal-support interaction and metal-reactant interaction can affect significantly the corresponding kinetics, as shown in our recent works. [16,17] To describe the overall behavior of the ripeningr esistance and quantify their relative contributions, it is important to describe all of them consistentlyi no ne framework and corresponding work is ongoing.…”

Section: Half-lifetime and Onset Temperature Of Ripeningmentioning

confidence: 99%

“…[16,17] Herein, we present ad etail evolution of dispersion, average size, and particle number for Ostwaldr ipening of supported particles under both isothermal and thermal conditions, from which corresponding half-lifetime and onset temperature were extracted to quantify the lifetime and thermal stability. [16,17] Herein, we present ad etail evolution of dispersion, average size, and particle number for Ostwaldr ipening of supported particles under both isothermal and thermal conditions, from which corresponding half-lifetime and onset temperature were extracted to quantify the lifetime and thermal stability.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, the influence of size and monodispersity on the ripeningk inetics of supported particles was addressed through kinetic simulation, whereas the influence of metal-support interaction and metal-reactant interaction on the ripening kinetics of supported particles was represented in our recent works. [16,17] Herein, we present ad etail evolution of dispersion, average size, and particle number for Ostwaldr ipening of supported particles under both isothermal and thermal conditions, from which corresponding half-lifetime and onset temperature were extracted to quantify the lifetime and thermal stability. Accordingly,t he phase-diagrams of half-lifetime and onset temperature overawide range of size and monodispersity are constructed fort he first time.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

2018

ChemCatChem

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Stability of dispersed particles on their supports is one of the central topics in heterogeneous catalysis and quantifying the influence of the particle size distribution on lifetime and thermal stability is highly valuable for rational design of efficient nanocatalysts. We report here a theoretical study of Ostwald ripening of supported particles, in particular, the kinetic evolution of particle number, average size, and dispersion with respect to time and thermal temperature in a wide range of size and monodispersity. Phase diagrams of half‐lifetime and onset temperature of ripening as functions of size and monodispersity were constructed. If decreasing the average particle size, though there is a modest gain in the dispersion, the stability declines dramatically; specifically, the half‐lifetime of ripening decreases exponentially and the corresponding onset temperature decreases by hundreds of Kelvin. Decline in stability owing to the decrease in size could, however, be systematically compensated by increasing the monodispersity of the size distribution. We find that the supported particles with the same half‐life time and onset temperature could originate from different particle size distributions, whereas the particle size distribution with the same apparent dispersion could have very different onset temperature and half‐lifetime. The result highlights the importance of both size and monodispersity in particle size distribution to the ripening resistance of supported particles, and the methodology developed for simulating ripening kinetics could be used to accelerate the aging protocols.

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Section: Resultsmentioning

confidence: 95%

Section: Half-lifetime and Onset Temperature Of Ripeningmentioning

confidence: 99%

Section: Half-lifetime and Onset Temperature Of Ripeningmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

2018

ChemCatChem

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Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO₂

Yuan

Zhang

et al. 2018

Angewandte Chemie

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Preventing sintering of supported nanocatalysts is an important issue in nanocatalysis.Afeasible wayi st oc hoose as uitable support. However,w hether the metal-support interactions promote or prevent the sintering has not been fully identified. Now,c ompletely different sintering behaviors of Au nanoparticles on distinct anatase TiO 2 surfaces have been determined by in situ TEM. The full in situ sintering processes of Au nanoparticles were visualized on TiO 2 (101) surface,w hich coupled the Ostwald ripening and particle migration coalescence.Incontrast, no sintering of Au on TiO 2 anatase (001) surface was observed under the same conditions. This facet-dependent sintering mechanism is fully explained by the density function theory calculations.T his work not only offers direct evidence of the important role of supports in the sintering process,b ut also provides insightful information for the design of sintering-resistant nanocatalysts.Metal nanoparticles (NPs) supported on oxide are of great importance in many industrial chemical processes as heterogeneous catalysts. [1] One of the key parameters controlling the activity is the size of the NP. [2] However, many reactions take place at elevated temperatures,inwhich the highly dispersed nanocatalysts with high surface energies are prone to sintering and thereby lose activity. [3] Therefore,u nderstanding the sintering mechanism of supported catalysts is of considerable importance in nanoscience and nanocatalysis research. Tw o mechanisms are generally considered for the sintering of nanoparticles:O stwald ripening (OR), which involves the migration of single atoms or small atomic clusters from smaller particles to larger particles;p article migration and coalescence (PMC), which involves the Brownian-like motion and coalesce of particles. [3a] Tr emendous efforts have been devoted to studying the two sintering mechanisms of supported catalysts. [3,4] Among these studies,t he effect of the metal-support interaction (MSI) on the sintering behavior is ahot topic and has been extensively discussed. [3][4][5] Strong MSI is considered to prevent PMC by stabilizing the supported nanoparticle,however, it is also argued that it could promote the OR by decreasing the activation energy of ripening.Thus, how MSI would affect the sintering process has not been fully identified, which becomes am ajor obstacle to the design of sintering-resistant nanocatalysts. [4a,5b, 6] To address this issue,direct experimental evidence linking the sintering behavior to MSI is necessary and required. As an emerging technology for sintering study,i nsitu transmission electron microscopy (TEM) [5a, 7] could visualize sintering processes at the atomic level, which is extremely crucial for unveiling the underlying mechanism. Exciting advances have been reported by in situ TEM in several supported catalyst systems,f or instance,P t/Al 2 O 3 , [7a] Cu/SiO 2 , [7g] Ni/MgAl 2 O 4 , [7i] etc. However, these studies focus on either determining the dominating sintering mechanism by statistic...

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Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO₂

Yuan

Zhang

et al. 2018

Angew Chem Int Ed

View full text Add to dashboard Cite

Preventing sintering of supported nanocatalysts is an important issue in nanocatalysis. A feasible way is to choose a suitable support. However, whether the metal–support interactions promote or prevent the sintering has not been fully identified. Now, completely different sintering behaviors of Au nanoparticles on distinct anatase TiO2 surfaces have been determined by in situ TEM. The full in situ sintering processes of Au nanoparticles were visualized on TiO2 (101) surface, which coupled the Ostwald ripening and particle migration coalescence. In contrast, no sintering of Au on TiO2 anatase (001) surface was observed under the same conditions. This facet‐dependent sintering mechanism is fully explained by the density function theory calculations. This work not only offers direct evidence of the important role of supports in the sintering process, but also provides insightful information for the design of sintering‐resistant nanocatalysts.

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Theoretical Investigation of Metal‐Support Interactions on Ripening Kinetics of Supported Particles

Cited by 17 publications

References 74 publications

Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO₂

Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO₂

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Theoretical Investigation of Metal‐Support Interactions on Ripening Kinetics of Supported Particles

Cited by 17 publications

References 74 publications

Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

Influence of Particle Size Distribution on Lifetime and Thermal Stability of Ostwald Ripening of Supported Particles

Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO2

Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO2

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Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO₂

Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO₂