Structure and Stability of Fe Nanocrystals: An Atomistic Study

Zhang, Yang; Ye, Wen; Zhu, Zi‐Zhong; Sun, Shi‐Gang

doi:10.1021/jp107709q

Cited by 31 publications

(16 citation statements)

References 38 publications

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“…So herein, photogenerated electrons and holes move in opposite directions, reducing the recombination probability and making charge separation more efficient, which lead to a higher photocatalytic activity. 29) This is in good agreement with the results obtained for EIS analyses (Fig. 8).…”

Section: Photocatalytic Mechanismsupporting

confidence: 92%

Magnetically recyclable MnFe2O4/polyaniline composite with enhanced visible light photocatalytic activity for rhodamine B degradation

Zeng¹,

Yang²,

Qiu³

et al. 2016

J. Ceram. Soc. Japan

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The magnetically recyclable MnFe 2 O 4 /Polyaniline (PANI) composite was successfully synthesized by a combination of a saltassisted solution combustion method and an in situ oxidative polymerization method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UVvis diffuse reflectance spectroscopy (DRS) were employed to characterize the physical and chemical properties of the samples. The results showed that MnFe 2 O 4 /PANI composite exhibited higher photocatalytic activity and stability than pure PANI and MnFe 2 O 4 nanoparticles toward the degradation of rhodamine B (RhB) under visible light irradiation, suggesting the existence of a synergic effect between PANI and MnFe 2 O 4 . The excited state electrons in the lowest unoccupied molecular orbital (LUMO) of PANI can readily migrate into conduction band (CB) of MnFe 2 O 4 , while the holes in the valence band (VB) of MnFe 2 O 4 migrate to the ³-orbital of PANI because of the enjoined electric fields of the two materials, which can further improve the separation of the photoinduced electronhole pairs.

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Section: Photocatalytic Mechanismsupporting

confidence: 92%

Magnetically recyclable MnFe2O4/polyaniline composite with enhanced visible light photocatalytic activity for rhodamine B degradation

Zeng¹,

Yang²,

Qiu³

et al. 2016

J. Ceram. Soc. Japan

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“…This is associated with a clear step change in U and corresponding local minimum in C p both at 1070 K from original EAM. It has been shown previously that, a solid-state transition is accompanied with a step change in U and a local minimum in C p , which was referred to as negative C p (Zhang et al, 2010). The J -L snapshots were taken close to melting point those showing a diagonal (corner to corner) melting which started at the bottom and moving up where (111) facet on the top can still be seen.…”

Section: Caloric Curvesmentioning

confidence: 99%

Size and shape-dependent melting mechanism of Pd nanoparticles

et al. 2018

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Molecular dynamics simulation is employed to understand the thermodynamic behavior of cuboctahedron (cub) and icosahedron (ico) nanoparticles with 2 − 20 number of full shells. The original embedded atom method (EAM) was compared to the more recent highly optimized version as interatomic potential. The thermal stability of clusters were probed using potential energy and specific heat capacity as well as structure analysis by radial distribution function (G(r)) and common neighbor analysis (CNA), simultaneously, to make a comprehensive picture of the solid state and melting transitions. The result shows ico is the only stable shape of small clusters (Pd 55 -Pd 309 using original EAM and Pd 55 using optimized version) those are melting uniformly due to their small diameter. An exception is cub Pd 309 modeled via optimized EAM that transforms to ico at elevated temperatures. A similar cub to ico transition was predicted by original EAM for Pd 923 -Pd 2075 clusters while for the larger clusters both cub and ico are stable up to the melting point. As detected by G(r) and CNA, moderate and large cub clusters were showing surface melting by nucleation of the liquid phase at (100) planes and growth of liquid phase at the surface before inward growth. While diagonal (one corner to another) melting was dominating over ico clusters owing to their partitioned

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“…Thus it is highly unlikely that local minimum or minor peak in C p are associated with surface melting. Apparently Zhang et al [33] were the first who noticed such a step change in the caloric curve and attributed it to a solid-state transition using CNA. Utilization of heat capacity has been also demonstrated for a more complex transition at elevated temperature in Pt-Pd alloy [34,35].…”

Section: Relaxationmentioning

confidence: 99%

Determining phase transition using potential energy distribution and surface energy of Pd nanoparticles

Azadeh

Kateb

Marashi

2019

Computational Materials Science

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Molecular dynamics simulation is employed to understand the thermodynamic behavior of cuboctahedron (cub) and icosahedron (ico) nanoparticles with 2 -20 number of shells (55 -28741 atoms). The embedded atom method was used to describe the interatomic potential. Conventional melting criteria such as potential energy and specific heat capacity (C p ) caloric curves as well as structure analysis by radial distribution function (G(r)) and common neighbor analysis (CNA) were utilized simultaneously to provide a comprehensive picture of the melting process. It is shown that the potential energy distribution and surface energy (γ p ) proposed here are holding several advantages over previous criteria. In particular, potential energy distribution can distinguish between interior and surface atoms and even corner, edge and plane atoms at the surface. While G(r) and CNA are not surface sensitive methods and cannot distinguish between surface melting and an allotropic transition. It is also shown that allotropic change appears more clearly in C p and γ p rather than potential energy. However, determining accurate C p requires enough sampling to be averaged. Finally, a few issues in the current methods for determining γ p were discussed and a simple method based on available models was proposed which, independent of estimation of the surface area, predicts the correct temperature and size-dependent trend in agreement with Guggenheim-Katayama and Tolman's models, respectively.

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Structure and Stability of Fe Nanocrystals: An Atomistic Study

Cited by 31 publications

References 38 publications

Magnetically recyclable MnFe<sub>2</sub>O<sub>4</sub>/polyaniline composite with enhanced visible light photocatalytic activity for rhodamine B degradation

Magnetically recyclable MnFe<sub>2</sub>O<sub>4</sub>/polyaniline composite with enhanced visible light photocatalytic activity for rhodamine B degradation

Size and shape-dependent melting mechanism of Pd nanoparticles

Determining phase transition using potential energy distribution and surface energy of Pd nanoparticles

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