Radiolytic generation of organic radical cations in zeolite Na-Y

Qin, Xue-Zhi; Trifunac, A. D.

doi:10.1021/j100374a069

Cited by 54 publications

(29 citation statements)

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“…Similarly oscillating interactions mediated by solvent structuring have been calculated for unpassivated nanoparticles with solvophilic surfaces [51][52][53] . Also in close analogy, surface forces between macroscopic SAMs 41 in good solvents are known to be sensitive to ligand ordering.…”

Section: Figures 2 and 3cmentioning

confidence: 99%

Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

2013

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We present the first nearly atomistic molecular dynamics study of nanorod-nanorod association in explicit solvent, showing that inter-rod forces can be dominated by microscopic factors absent in common continuum descriptions. Specifically, we find that alkane ligands on faceted CdS nanorods in n-hexane undergo a temperature-dependent order-disorder transition akin to that of self-assembled monolayers on macroscopic substrates. This collective ligand alignment organizes nearby solvent molecules, strongly influencing the statistics of rod-rod separation. The strong temperature dependence of this mechanism could be exploited in the laboratory to manipulate and optimize the assembly of ordered structures.

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Section: Figures 2 and 3cmentioning

confidence: 99%

Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

2013

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“…Given that the typical surface energy of PEO is ~40 mN/m, 58 the drag force exerted on a 1 nm particle is ~10 -1 nN, which is comparable to or larger than the typical solvation and van der Waals interactions between nanoparticles of similar sizes. [59][60] Therefore, the fluid edge dragging effect, which increases as the fluid edge passes through the particle, is able to induce the acceleration of the particle before coalescence.…”

Section: Force States Of the Coalescing Nanoparticlesmentioning

confidence: 99%

Windowless Observation of Evaporation-Induced Coarsening of Au–Pt Nanoparticles in Polymer Nanoreactors

Chen

Meckes

et al. 2018

J. Am. Chem. Soc.

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The interactions between nanoparticles and solvents play a critical role in the formation of complex, metastable nanostructures. However, direct observation of such interactions with high spatial and temporal resolution is challenging with conventional liquid-cell transmission electron microscopy (TEM) experiments. Here, a windowless system consisting of polymer nanoreactors deposited via scanning probe block copolymer lithography (SPBCL) on an amorphous carbon film is used to investigate the coarsening of ultrafine (1-3 nm) Au-Pt bimetallic nanoparticles as a function of solvent evaporation. In such reactors, homogeneous Au-Pt nanoparticles are synthesized from metal-ion precursors in situ under electron irradiation. The nonuniform evaporation of the thin polymer film not only concentrates the nanoparticles but also accelerates the coalescence kinetics at the receding polymer edges. Qualitative analysis of the particle forces influencing coalescence suggests that capillary dragging by the polymer edges plays a significant role in accelerating this process. Taken together, this work (1) provides fundamental insight into the role of solvents in the chemistry and coarsening behavior of nanoparticles during the synthesis of polyelemental nanostructures, (2) provides insight into how particles form via the SPBCL process, and (3) shows how SPBCL-generated domes, instead of liquid cells, can be used to study nanoparticle formation. More generally, it shows why conventional models of particle coarsening, which do not take into account solvent evaporation, cannot be used to describe what is occurring in thin film, liquid-based syntheses of nanostructures.

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“…[40][41][42] In addition to their organized microporous frameworks, an important advantage of zeolites is to offer a high surface area and a cationic exchange capacity that is expected to facilitate the ionization of the adsorbed aromatic molecules and to help creating persistent charge separated states. Moreover, even though the ionization process can be initiated either electrochemically 43 or by photoexcitation 42,[44][45][46][47][48] or radiolysis, 49,50 it can also occur spontaneously if the ionization potential of the molecule is sufficiently low and if the energy of polarization in the zeolite channel is high enough. 40 As a whole, stabilization of the separated charge states in the zeolite can thus be considered as an intrinsic property of the inner charged surface of the zeolite micropores space.…”

Section: Introductionmentioning

confidence: 99%

Electron transfers in a TiO₂-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule

Legrand

Moissette

Hureau

et al. 2014

Phys. Chem. Chem. Phys.

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New assemblies constituted by a microporous matrix of mordenite (MOR) zeolite on which TiO2 nanoclusters are deposited were synthesized using ionic oxalate complexes and TiCl3 titanium precursors. The samples were used to investigate the transfer of electrons produced by spontaneous or photo-induced ionization of a guest molecule (t-stilbene, t-St) occluded in the porous volume towards the conduction band of a conductive material placed nearby, in the pores or at least close to their entrance. The reaction mechanisms were compared in these Ti-rich solids and in a Ti-free mordenite sample. The characterization by XRD, N2 physisorption, TEM, XPS and DRIFT spectroscopy of the supramolecular TiO2/MOR systems before t-St adsorption showed the preservation of the crystalline structure after Ti addition and thermal activation treatments. They also revealed that titanium is mainly located at the external surface of the zeolite grains, in the form of highly dispersed and/or aggregated anatase. After incorporation of the guest molecule in the new assemblies, diffuse reflectance UV-visible and EPR spectroscopies indicate that the electron transfer processes are similar with and without TiO2 but strongly stabilized t-St˙(+) radicals are detected in the TiO2-MOR samples whereas such species were never detected earlier in TiO2-free mordenite using these techniques. The stabilization process is found to be more efficient in the sample prepared with TiCl3 as the precursor than with titanium oxalates. It is proposed that the proximity of TiO2 with the formed t-St˙(+) radicals provokes the stabilization of the radical through capture of the ejected electron by the semi-conductor and that confinement effects can also play a role.

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Radiolytic generation of organic radical cations in zeolite Na-Y

Cited by 54 publications

References 0 publications

Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

Windowless Observation of Evaporation-Induced Coarsening of Au–Pt Nanoparticles in Polymer Nanoreactors

Electron transfers in a TiO₂-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule

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Radiolytic generation of organic radical cations in zeolite Na-Y

Cited by 54 publications

References 0 publications

Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

Orientational Ordering of Passivating Ligands on CdS Nanorods in Solution Generates Strong Rod–Rod Interactions

Windowless Observation of Evaporation-Induced Coarsening of Au–Pt Nanoparticles in Polymer Nanoreactors

Electron transfers in a TiO2-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule

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Electron transfers in a TiO₂-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule