scholarly journals Crumpled Graphene-Storage Media for Hydrogen and Metal Nanoclusters

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2098
Author(s):  
Liliya R. Safina ◽  
Karina A. Krylova ◽  
Ramil T. Murzaev ◽  
Julia A. Baimova ◽  
Radik R. Mulyukov
Keyword(s):  
Additional Treatment ◽  
Dynamics Simulation ◽  
Structural Behavior ◽  
Metal Nanoclusters ◽  
Hydrogen Atoms ◽  
Graphene Flake ◽  
Hydrogen Molecules ◽  
Storage Media ◽  
Metal Nanocluster ◽  
Crumpled Graphene

Understanding the structural behavior of graphene flake, which is the structural unit of bulk crumpled graphene, is of high importance, especially when it is in contact with the other types of atoms. In the present work, crumpled graphene is considered as storage media for two types of nanoclusters—nickel and hydrogen. Crumpled graphene consists of crumpled graphene flakes bonded by weak van der Waals forces and can be considered an excellent container for different atoms. Molecular dynamics simulation is used to study the behavior of the graphene flake filled with the nickel nanocluster or hydrogen molecules. The simulation results reveal that graphene flake can be considered a perfect container for metal nanocluster since graphene can easily cover it. Hydrogen molecules can be stored on graphene flake at 77 K, however, the amount of hydrogen is low. Thus, additional treatment is required to increase the amount of stored hydrogen. Remarkably, the size dependence of the structural behavior of the graphene flake filled with both nickel and hydrogen atoms is found. The size of the filling cluster should be chosen in comparison with the specific surface area of graphene flake.

Investigation of the Hydrogen Transport Processes in Crystalline Silicon of n-Type Conductivity

2007 ◽  
Vol 131-133 ◽  
pp. 425-430 ◽  
Author(s):  
Anis M. Saad ◽  
Oleg Velichko ◽  
Yu P. Shaman ◽  
Adam Barcz ◽  
Andrzej Misiuk ◽  
...  
Keyword(s):  
Hydrogen Concentration ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Transport Processes ◽  
Concentration Profiles ◽  
Hydrogen Transport ◽  
Hydrogen Atoms ◽  
Near Surface ◽  
Type Conductivity ◽  
Hydrogen Molecules

The silicon substrates were hydrogenated at approximately room temperature and hydrogen concentration profiles vs. depth have been measured by SIMS. Czochralski grown (CZ) wafers, both n- and p-type conductivity, were used in the experiments under consideration. For analysis of hydrogen transport processes and quasichemical reactions the model of hydrogen atoms diffusion and quasichemical reactions is proposed and the set of equations is obtained. The developed model takes into account the formation of bound hydrogen in the near surface region, hydrogen transport as a result of diffusion of hydrogen molecules 2 H , diffusion of metastable complexes * 2 H and diffusion of nonequilibrium hydrogen atoms. Interaction of 2 H with oxygen atoms and formation of immobile complexes “oxygen atom - hydrogen molecule” (O - H2 ) is also taken into account to explain the hydrogen concentration profiles in the substrates of n-type conductivity. The computer simulation based on the proposed equations has shown a good agreement of the calculated hydrogen profiles with the experimental data and has allowed receiving a value of the hydrogen molecules diffusivity at room temperature.

MOLECULAR DYNAMICS SIMULATION ON HYDROGEN STORAGE IN METALLIC NANOPARTICLES

2009 ◽  
Vol 08 (01n02) ◽  
pp. 39-42 ◽  
Author(s):  
HIROSHI OGAWA ◽  
AKINORI TEZUKA ◽  
HAO WANG ◽  
TAMIO IKESHOJI ◽  
MASAHIKO KATAGIRI
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Storage ◽  
Metallic Nanoparticles ◽  
Structural Modification ◽  
Structural Features ◽  
Dynamics Simulation ◽  
Metallic Nanoparticle ◽  
Hydrogen Atoms ◽  
Diffusion Of Hydrogen ◽  
Storage Properties

Hydrogen storage in a metallic nanoparticle was simulated by classical molecular dynamics. Distribution of hydrogen atoms inside nanoparticle was investigated by changing length and energy parameters of metal– H bonds. Hydrogen atoms diffused into the particle and distributed homogeneously in case of weak metal– H bonds. In case of strong metal– H bonds, a hydrogen-rich surface layer was observed which suppresses the inward diffusion of hydrogen atoms. Structural modification of nanoparticle accompanied by grain boundary formation due to hydrogen loading was also observed. These variations in dynamical and structural features are considered to affect the hydrogen storage properties in nanoparticles.

Molecular Dynamics Studies on the Growth and Structural Properties of Hydrogenated DLC Films

2008 ◽  
Vol 373-374 ◽  
pp. 108-112
Author(s):  
Yu Jun Zhang ◽  
Guang Neng Dong ◽  
Jun Hong Mao ◽  
You Bai Xie
Keyword(s):  
Molecular Dynamics ◽  
Structural Properties ◽  
Impact Energy ◽  
Frictional Coefficient ◽  
Carbon Films ◽  
Dynamics Simulation ◽  
Diamond Surface ◽  
Hydrogen Atoms ◽  
Molecular Configuration ◽  
The Impact

The novel frictional properties of hydrogenated DLC (Diamond-like Carbon) films have been reported for nearly ten years. But up to now, researchers still haven’t known the exact mechanism resulting in the super-low frictional performance of hydrogenated DLC films. Especially they have little knowledge on the molecular configuration and structural properties of these kinds of films. In this paper, CH3 radicals with different impact energies are selected as source species to deposit DLC films on diamond (100) by molecular dynamics simulation. Results show hydrogenated DLC films can be successfully obtained when impact energy is in an appropriate scope that is no less than 20eV. The depositing processes involve impinging diamond surface and bonding procedure. Some atoms, instead of bonding with substrate atoms, fly away from the diamond surface. Only suitable impact energy can improve the growth of the film. Within 30eV to 60eV, the maximum deposition ratio is attained. In addition, when carbon atoms act as the deposition sources, the deposition ratio is relatively higher. Furthermore, the authors find that species with higher concentration of carbon atoms in deposition sources lead to a better deposition rate. Carbon atoms are more reactive than hydrogen atoms. Then the relative densities of DLC films are calculated. The density curves indicate that the structures of the films vary obviously as the impact energy augments. The average relative density is generally monotone increase with the increment of impact energy. The hybridization of carbon atoms greatly affects the properties of hydrogenated DLC films. The transition between sp2 and sp3 will result in the graphitization and reduce the frictional coefficient when DLC films are used as tribo-pair in friction.

Carbon nanopore and anchoring site–assisted general construction of encapsulated metal (Rh, Ru, Ir) nanoclusters for highly efficient hydrogen evolution in pH–universal electrolytes and natural seawater

2021 ◽  
Author(s):  
Rong Ding ◽  
Tingting Yan ◽  
Yi Wang ◽  
Yan Long ◽  
Guangyin Fan
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
General Construction ◽  
Natural Seawater ◽  
Metal Nanoclusters ◽  
Hydrogen Economy ◽  
Ligand Free ◽  
Metal Nanocluster ◽  
Substantial Interest ◽  
Free Metal

Metal–nanocluster–catalyzed hydrogen evolution through water splitting has received substantial interest toward the implementation of hydrogen economy. However, the general and efficient fabrication of well–defined and ligand–free metal nanoclusters (NCs) with...

scholarly journals Long-Time Non-Debye Kinetics of Molecular Desorption from Substrates with Frozen Disorder

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3662
Author(s):  
Victor N. Bondarev ◽  
Volodymyr V. Kutarov ◽  
Eva Schieferstein ◽  
Vladimir V. Zavalniuk
Keyword(s):  
Second Order ◽  
Order Effects ◽  
Desorption Kinetics ◽  
Hydrogen Atoms ◽  
Closed Expression ◽  
Hydrogen Molecules ◽  
Long Time ◽  
Second Order Effects ◽  
Molecular Desorption ◽  
Kinetics Of

The experiments on the kinetics of molecular desorption from structurally disordered adsorbents clearly demonstrate its non-Debye behavior at “long” times. In due time, when analyzing the desorption of hydrogen molecules from crystalline adsorbents, attempts were made to associate this behavior with the manifestation of second-order effects, when the rate of desorption is limited by the rate of surface diffusion of hydrogen atoms with their subsequent association into molecules. However, the estimates made in the present work show that the dominance of second-order effects should be expected in the region of times significantly exceeding those where the kinetics of H2 desorption have long acquired a non-Debye character. To explain the observed regularities, an approach has been developed according to which frozen fluctuations in the activation energy of desorption play a crucial role in the non-Debye kinetics of the process. The obtained closed expression for the desorption rate has a transparent physical meaning and allows us to give a quantitative interpretation of a number of experiments on the desorption kinetics of molecules not only from crystalline (containing frozen defects) but also from amorphous adsorbents. The ways of further development of the proposed theory and its experimental verification are outlined.

scholarly journals Novel huperzine A based NMDA antagonists: insights from molecular docking, ADME/T and molecular dynamics simulation studies

RSC Advances ◽  
2020 ◽  
Vol 10 (43) ◽  
pp. 25446-25455
Author(s):  
Dilep Kumar Sigalapalli ◽  
Raghu Rangaswamy ◽  
Neelima D. Tangellamudi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Molecular Dynamics Simulation ◽  
Huperzine A ◽  
Dynamics Simulation ◽  
Structural Behavior ◽  
Nmda Receptor Antagonists ◽  
Binding Affinities ◽  
Nmda Antagonists ◽  
Simulation Studies

The in silico study explores the structural behavior and binding affinities of 40 novel analogues of huperzine A. Novel NMDA receptor antagonists have been virtually identified by molecular docking, ADME/T and molecular dynamics simulation studies.

scholarly journals The scattering of hydrogen positive rays, and the existence of a powerful field of force in the hydrogen molecule

1922 ◽  
Vol 102 (715) ◽  
pp. 197-209 ◽  
Keyword(s):  
Electric Fields ◽  
General Scheme ◽  
Hydrogen Gas ◽  
Theoretical Interpretation ◽  
Scattering Medium ◽  
Hydrogen Atoms ◽  
Hydrogen Molecules ◽  
Nuclear Particle ◽  
Positively Charged ◽  
Made In

In view of the extremely important results obtained by Sir E. Rutherford and others from a study of the scattering of α -rays, it seemed worth while to investigate the scattering of particles moving with smaller velocities such as occur in the positive rays. The most interesting, because the simplest, are the rays of positively charged hydrogen atoms, which presumably consist simply of a nuclear particle, or proton. The experiments described in this paper were made in some cases with these rays, in others with the positively charged hydrogen molecules, systems consisting of two protons and one electron. The scattering medium was in all cases hydrogen gas. This was chosen largely for convenience, as the experimental arrangement is considerably simplified if the same gas is used to produce the rays and to scatter them, and also because, with the exception of helium, the molecule of hydrogen is the simplest known, and there seemed more hope of obtaining results which could be given a definite theoretical interpretation. The general scheme of experiment was to produce the rays in a discharge tube, analyse them by magnetic and electric fields in the ordinary way, cut off all except those of the kind required by a slotted diaphragm, pass the remainder through a chamber containing the scattering gas, and receive them in a Faraday cylinder arranged behind a slit of variable width. The experiment consisted in finding how the charge received by the Faraday cylinder varied with the width of the slit, when this was made wider than the geometrical “shadow” of the slot in the diaphragm. Any rays lying outside this “shadow” must have been scattered.

scholarly journals Molecular-Dynamics Simulation of Self-Diffusion of Molecular Hydrogen in X-Type Zeolite

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoming Du
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Hydrogen Diffusion ◽  
Mean Free Path ◽  
The Self ◽  
Dynamics Simulation ◽  
Pulse Field ◽  
Self Diffusion ◽  
Hydrogen Molecules ◽  
Dynamics Simulations

The self-diffusion of hydrogen in NaX zeolite has been studied by molecular-dynamics simulations for various temperatures and pressures. The results indicate that in the temperature range of 77–293 K and the pressure range of 10–2700 kPa, the self-diffusion coefficients are found to range from 1.61 × 10−9 m2·s−1to 3.66 × 10−8 m2·s−1which are in good agreement with the experimental values from the quasielastic neutron scattering (QENS) and pulse field gradients nuclear magnetic resonance (PFG NMR) measurements. The self-diffusion coefficients decrease with increasing pressure due to packing of sorbate-sorbate molecules which causes frequent collusion among hydrogen molecules in pores and increase with increasing temperature because increasing the kinetic energy of the gas molecules enlarges the mean free path of gas molecule. The activated energy for hydrogen diffusion determined from the simulation is pressure-dependent.

Synthesis and ROMP of Metal Nanocluster Containing Norbornene Derivatives

2001 ◽  
Vol 704 ◽  
Author(s):  
James H. Wynne ◽  
Christopher T. Lloyd ◽  
Steven E. Bullock ◽  
Robert F. Cozzens
Keyword(s):  
Ring Opening ◽  
Optical Materials ◽  
Homogeneous Catalyst ◽  
Metal Nanoclusters ◽  
Block Polymers ◽  
Metathesis Polymerization ◽  
Metal Nanocluster ◽  
Norbornene Derivatives ◽  
Size Controlled ◽  
Diblock Polymers

AbstractWe report the synthesis of a series of highly functional metal chelated silyl- and tert-butyl-protected 2, 3-diaminomethyl norbornene derivatives. Subsequent alterations to the previously synthesized norbornene adducts afford many other derivatives containing such functionalities as alkyl, cyano, esters, and ethers. These derivatives are then subjected to ring-opening metathesis polymerization (ROMP) employing a ruthenium homogeneous catalyst to afford phase separated block polymers. The block polymers formed serve as unique templates for the formation of size controlled metal nanoclusters having a narrow dispersion. These metal nanoclusters containing diblock polymers are evaluated as unique electrical and optical materials.

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