Modelling nucleation and nano-particle structures

Mora-Fonz, Miguel J.; Hamad, Said; Catlow, C. Richard A.

doi:10.1080/00268970701211626

Cited by 9 publications

(17 citation statements)

References 36 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…40 and 41, which also place these studies into the context of the wider field of computational modeling of nano-clusters. Moreover, although much remains to be done, the calculations establish the viability and value of modeling in studying the early stages of zeolite synthesis.…”

Section: Review Articlementioning

confidence: 95%

“…35,36 Such an approach was employed by Mora-Fonz et al, [37][38][39][40] where the basis was still DFT calculations, but explicit water was included and the whole silicate-water complex was embedded in the continuum-like representation of solvation available in the ''COSMO'' approach. Upon water removal, a negatively charged dimer is formed.…”

Section: Review Articlementioning

confidence: 99%

“…256 A wealth of theoretical data is available on the topic, 257-261 but we focus herein on the adsorption and nature of the intermediates occurring during alkene cracking. 40 Pathway of the molecule in the porous network. The physisorption strength of alkanes is known to increase linearly with the carbon number.…”

Section: View Article Onlinementioning

confidence: 99%

See 2 more Smart Citations

Advances in theory and their application within the field of zeolite chemistry

et al. 2015

View full text Add to dashboard Cite

Zeolites are versatile and fascinating materials which are vital for a wide range of industries, due to their unique structural and chemical properties, which are the basis of applications in gas separation, ion exchange and catalysis. Given their economic impact, there is a powerful incentive for smart design of new materials with enhanced functionalities to obtain the best material for a given application. Over the last decades, theoretical modeling has matured to a level that model guided design has become within reach. Major hurdles have been overcome to reach this point and almost all contemporary methods in computational materials chemistry are actively used in the field of modeling zeolite chemistry and applications. Integration of complementary modeling approaches is necessary to obtain reliable predictions and rationalizations from theory. A close synergy between experimentalists and theoreticians has led to a deep understanding of the complexity of the system at hand, but also allowed the identification of shortcomings in current theoretical approaches. Inspired by the importance of zeolite characterization which can now be performed at the single atom and single molecule level from experiment, computational spectroscopy has grown in importance in the last decade. In this review most of the currently available modeling tools are introduced and illustrated on the most challenging problems in zeolite science. Directions for future model developments will be given.

show abstract

Section: Review Articlementioning

confidence: 95%

Section: Review Articlementioning

confidence: 99%

See 1 more Smart Citation

Advances in theory and their application within the field of zeolite chemistry

et al. 2015

View full text Add to dashboard Cite

show abstract

“…They observed that at time scales shorter than 0.5 ns fourmembered rings will be most common, while at time scales longer than 1 ns five-membered rings will dominate. Very recently, Mora-Fonz et al have shown the importance of solvent and pH to control specific oligomerization and cyclization processes in the nucleation of microporous silicas [56,57]. Wu and Deem have shown that the nucleation barrier of silica without templates at high pH (*12) lies around 50 T atoms [58].…”

Section: Introductionmentioning

confidence: 97%

Multi-level Modeling of Silica–Template Interactions During Initial Stages of Zeolite Synthesis

et al. 2009

View full text Add to dashboard Cite

Zeolite synthesis is driven by structure-directing agents, such as tetrapropyl ammonium ions (TPA ? ) for Silicalite-1 and ZSM-5. However, the guiding role of these organic templates in the complex assembly to highly ordered frameworks remains unclear, limiting the prospects for advanced material synthesis. In this work, both static ab initio and dynamic classical modeling techniques are employed to provide insight into the interactions between TPA ? and Silicalite-1 precursors. We find that as soon as the typical straight 10-ring channel of Silicalite-1 or ZSM-5 is formed from smaller oligomers, the TPA ? template is partially squeezed out of the resulting cavity. Partial retention of the template in the cavity is, however, indispensable to prevent collapse of the channel and subsequent hydrolysis.

show abstract

“…Polymorph selection is important for controlling structure during the synthesis of materials from pharmaceuticals [27][28][29][30] to zeolites 31,32 and biominerals. Polymorph selection is important for controlling structure during the synthesis of materials from pharmaceuticals [27][28][29][30] to zeolites 31,32 and biominerals.…”

Section: Introductionmentioning

confidence: 99%

Competing nucleation pathways in a mixture of oppositely charged colloids: Out-of-equilibrium nucleation revisited

Peters

2009

The Journal of Chemical Physics

View full text Add to dashboard Cite

Recent simulations of crystal nucleation from a compressed liquid of oppositely charged colloids show that the natural Brownian dynamics results in nuclei of a charge-disordered FCC (DFCC) solid whereas artificially accelerated dynamics with charge swap moves result in charge-ordered nuclei of a CsCl phase. These results were interpreted as a breakdown of the quasiequilibrium assumption for precritical nuclei. We use structure-specific nucleus size coordinates for the CsCl and DFCC structures and equilibrium based sampling methods to understand the dynamical effects on structure selectivity in this system. Nonequilibrium effects observed in previous simulations emerge from a diffusion tensor that dramatically changes when charge swap moves are used. Without the charge swap moves diffusion is strongly anisotropic with very slow motion along the charge-ordered CsCl axis and faster motion along the DFCC axis. Kramers-Langer-Berezhkovskii-Szabo theory predicts that under the realistic dynamics, the diffusion anisotropy shifts the current toward the DFCC axis. The diffusion tensor also varies with location on the free energy landscape. A numerical calculation of the current field with a diffusion tensor that depends on the location in the free energy landscape exacerbates the extent to which the current is skewed toward DFCC structures. Our analysis confirms that quasiequilibrium theories based on equilibrium properties can explain the nonequilibrium behavior of this system. Our analysis also shows that using a structure-specific nucleus size coordinate for each possible nucleation product can provide mechanistic insight on selectivity and competition between nucleation pathways.

show abstract

Modelling nucleation and nano-particle structures

Cited by 9 publications

References 36 publications

Advances in theory and their application within the field of zeolite chemistry

Advances in theory and their application within the field of zeolite chemistry

Multi-level Modeling of Silica–Template Interactions During Initial Stages of Zeolite Synthesis

Competing nucleation pathways in a mixture of oppositely charged colloids: Out-of-equilibrium nucleation revisited

Contact Info

Product

Resources

About