Effects of plasma treatment parameters on the adsorption properties of tin dioxide-based nanomaterials

We have studied the effect of nitrogen plasma exposure on the adsorption properties of SnO2-based nanomaterials synthesized by the sol-gel method. We have established the correlation between the adsorption properties and plasma treatment parameters. The scanning electron microscopy has confirmed integrity violation of the original structure of nanomaterials and an increase in their specific surface area with high-power plasma source.

Modification of the Adsorption Properties of Nanomaterials Based on Zinc Oxide and Tin Dioxide after Additional Activation in Argon Plasma

The modification of the adsorption properties of nanomaterials based on ZnO and SnO2, synthesized by the sol-gel method, after additional activation of their surface by argon plasma has been studied. Correlation between the adsorption properties and photocatalytic activity has been established. The scanning electron microscopy has confirmed the degradation of structure of nanomaterials with high-power plasma source and/or prolonged activation, and as a consequence, reduction of their photocatalytic properties

Non-covalent interactions of Cysteine onto C60, C59Si, and C59Ge: A DFT study

The study of intermolecular interactions is of great importance. This study attempted to quantitatively examine the interactions between Cysteine (C3H7NO2S) and fullerene nanocages, C60, in a vacuum. As the frequent introduction of elements as impurities into the structure of nanomaterials can increase the intensity of intermolecular interactions, nanocages doped with silicon and germanium have also been studied as adsorbents C59Si and C59Ge. Quantum mechanical studies of such systems are possible in the density functional theory (DFT) framework. For this purpose, various functionals, such as B3LYP-D3, ωB97XD, and M062X, have been used. One of the most suitable basis functionals for the systems studied in this research is 6-311G (d), which has been used in both optimization calculations and calculations related to wave function analyses. The main part of this work is the study of various analyses that reveal the nature of the intermolecular interactions between the two components introduced above. The results of conceptual DFT, natural bond orbital, non-covalent interactions, and quantum theory of atoms in molecules were consistent and favored physical adsorption in all systems. Germanium had more adsorption energy than other dopants. The HOMO–LUMO energy gaps were as follows: C60: 5.996, C59Si: 5.309, and C59Ge: 5.188 eV at B3LYP-D3/6-311G (d) model chemistry. The adsorption sensitivity increased when an amino acid molecule interacted with doped C60, and this capability could be used to design a nanocarrier to detect Cysteine amino acids.

Intermolecular Interactions Between Serine and C60, C59Si, and C59Ge: A DFT Study

The study of intermolecular interactions is of great importance. This study attempted to quantitatively examine the interactions between Serine (C3H7NO3) and fullerene nanocages, C60, in vacuum. As the frequent introduction of elements as impurities into the structure of nanomaterials can increase the intensity of intermolecular interactions, nanocages doped with silicon and germanium have also been studied as adsorbents, C59Si and C59Ge. Quantum mechanical studies of such systems are possible in the density functional theory (DFT) framework. For this purpose, various functionals, such as B3LYP-D3, ωB97XD, and M062X, have been used. One of the most suitable basis functionals for the systems studied in this research is 6-311G (d), which has been used in both optimization calculations and calculations related to wave function analyses. The main part of this work is the study of various analyses that reveal the nature of the intermolecular interactions between the two components introduced above. The results of conceptual DFT, natural bond orbital, non-covalent interactions, and quantum theory of atoms in molecules were consistent and in favor of physical adsorption in all systems. Germanium had more adsorption energy than other dopants. The HOMO–LUMO energy gaps were as follows: C60: 5.996, C59Si: 5.309, and C59Ge: 5.188 eV at B3LYP-D3/6-311G (d) model chemistry. The sensitivity of the adsorption increased when an amino acid molecule interacted with doped C60, and this capability could be used to design nanocarrier to detect Serine amino acid.

Modulating Electronic Structure of Nanomaterials to Enhance Polysulfides Confinement for Advanced Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) battery is one of the most promising next-generation energy-storage systems. Nevertheless, owing to the low conductivity of sulfur species and the sluggish redox reaction, plenty of soluble lithium...

There's no place like real-space: elucidating size-dependent atomic structure of nanomaterials using pair distribution function analysis

We review the use of pair distribution function analysis for characterization of atomic structure in nanomaterials.

Influence of temperature on the displacement threshold energy in graphene

The atomic structure of nanomaterials is often studied using transmission electron microscopy. In addition to image formation, the energetic electrons impinging on the sample may also cause damage. In a good conductor such as graphene, the damage is limited to the knock-on process caused by elastic electron-nucleus scattering. This process is determined by the kinetic energy an atom needs to be sputtered, i.e. its displacement threshold energy Ed. This is typically assumed to have a fixed value for all electron impacts on equivalent atoms within a crystal. Here we show using density functional tight-binding simulations that the displacement threshold energy is affected by thermal perturbations of atoms from their equilibrium positions. This effect can be accounted for in the estimation of the displacement cross section by replacing the constant threshold energy value with a distribution. Our refined model better describes previous precision measurements of graphene knock-on damage, and should be considered also for other low-dimensional materials.

Reverse Monte Carlo modeling for low-dimensional systems

Reverse Monte Carlo (RMC) is one of the commonly used approaches for modeling total scattering data. However, to extend the capability of the RMC method for refining the structure of nanomaterials, the dimensionality and finite size need to be considered when calculating the pair distribution function (PDF). To achieve this, the simulation box must be set up to remove the periodic boundary condition in one, two or three of the dimensions. This then requires a correction to be applied for the difference in number density between the real system and the simulation box. In certain circumstances an analytical correction for the uncorrelated pairings of atoms is also applied. The validity and applicability of our methodology is demonstrated by applying the algorithms to simulate the PDF patterns of carbon systems with various dimensions, and also by using them to fit experimental data of CuO nanoparticles. This alternative approach for characterizing the local structure of nano-systems with the total scattering technique will be made available via the RMCProfile package. The theoretical formulation and detailed explanation of the analytical corrections for low-dimensional systems – 2D nanosheets, 1D nanowires and 0D nanoparticles – is also given.