scholarly journals Local Pressure of Supercritical Adsorbed Hydrogen in Nanopores

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2235 ◽  
Author(s):  
Jimmy Romanos ◽  
Sara Abou Dargham ◽  
Roy Roukos ◽  
Peter Pfeifer
Keyword(s):  
Binding Energy ◽  
Hydrogen Storage ◽  
Lattice Gas ◽  
Adsorbed Hydrogen ◽  
Local Pressure ◽  
Average Binding Energy ◽  
Adsorbed Phase ◽  
Absolute Adsorption ◽  
Sorbent Materials ◽  
Low Coverage

An overview is given of the development of sorbent materials for hydrogen storage. Understanding the surface properties of the adsorbed film is crucial to optimize hydrogen storage capacities. In this work, the lattice gas model (Ono-Kondo) is used to determine the properties of the adsorbed hydrogen film from a single supercritical hydrogen isotherm at 77 K. In addition, this method does not require a conversion between gravimetric excess adsorption and absolute adsorption. The overall average binding energy of hydrogen is 4.4 kJ/mol and the binding energy at low coverage is 9.2 kJ/mol. The hydrogen film density at saturation is 0.10 g/mL corresponding to a local pressure of 1500 bar in the adsorbed phase.

High Capacity Hydrogen Storage in Li Decorated Octagraphene - A First Principles Study

2017 ◽  
Vol 17 ◽  
pp. 131-139 ◽  
Author(s):  
B. Rekha ◽  
S. Seenithurai ◽  
R. Kodi Pandyan ◽  
S. Vinodh Kumar ◽  
Manickam Mahendran
Keyword(s):  
Binding Energy ◽  
Hydrogen Storage ◽  
First Principles ◽  
Density Functional ◽  
Storage Capacity ◽  
Hydrogen Adsorption ◽  
Pristine Graphene ◽  
Carbon Allotrope ◽  
Average Binding Energy ◽  
Hydrogen Molecules

From first principles density functional theory, Li-decorated octagraphene and its usage as a hydrogen storage media is theoretically investigated. Octagraphene is a versatile structure with periodic sp2 – bonded carbon atomic planar sheet. This carbon allotrope consists of carbon octagons and rectangular lattices with two bond lengths. The Li binding energy in octagraphene is 2.5 eV, which is much higher than that of pristine graphene. Maximum of four hydrogen molecules can be adsorbed on Li decorated on one side of octagraphene and this leads to a gravimetric storage capacity of 2.4 wt% with an average adsorption binding energy of 0.35eV/H2. Li decorated on both sides of octagraphene, attains a gravimetric storage capacity of 8.1 wt% with an average binding energy of 0.23 eV/ H2. Thus, the structure investigated here is flattering for the reversible hydrogen adsorption/ desorption at the room temperature.

scholarly journals A Method for the Determination of Composition Profiles in Industrial Air Separation, Pressure Swing Adsorption Systems

2003 ◽  
Vol 21 (1) ◽  
pp. 35-52 ◽  
Author(s):  
C.C.K. Beh ◽  
P.A. Webley
Keyword(s):  
Energy Balance Equation ◽  
Nitrogen Loading ◽  
Air Separation ◽  
Local Pressure ◽  
Vacuum Swing Adsorption ◽  
Adsorbed Phase ◽  
Composition Profiles ◽  
Pressure Swing ◽  
Monitoring And Diagnostics ◽  
Adsorption Systems

A simplified energy-balance equation has been proposed as an aid to online measurement of the adsorbed-phase nitrogen loading in industrial-scale pressure and vacuum swing adsorption systems consisting of one preferentially adsorbed component. Implementation of this technique to current and future plants requires the addition of thermocouples (which are relatively inexpensive) located axially through the bed and pressure transmitters at the bottom and top of the bed. This methodology has the advantage that the composition front may be inferred accurately from direct measurements of the local pressure and temperature, and used as the basis for process monitoring and diagnostics of plant purity, recovery and production rate.

Absolute Adsorption of CH4 on Shale with the Simplified Local-Density Theory

SPE Journal ◽  
2019 ◽  
Vol 25 (01) ◽  
pp. 212-225 ◽  
Author(s):  
Yueliang Liu ◽  
Jian Hou ◽  
Chen Wang
Keyword(s):  
Local Density ◽  
Molecular Simulations ◽  
Pore Wall ◽  
Excess Adsorption ◽  
Adsorbed Phase ◽  
Absolute Adsorption ◽  
Ch4 Adsorption ◽  
The Absolute ◽  
Two Parameters ◽  
Organic Pores

Summary Using a thermogravimetric (TGA) method, the excess methane (CH4) adsorption of four organic shale samples is measured at temperatures of 303.15 to 383.15 K and pressures of 0 to 15.0 MPa. Simplified-local-density (SLD) theory is used to calculate the density distribution of CH4 in nanopores, which is then used to obtain the adsorbed CH4 density on four shale samples. Such density is applied to obtain the absolute CH4 adsorption by correcting the measured excess CH4 adsorption. SLD theory shows that the adsorbed CH4 density is strongly affected by temperature and pressure, as well as the pore size, which is in line with the previous findings from molecular simulations. SLD theory captures the density of the adsorbed phase of CH4 in the presence of CH4/pore-wall interactions. However, the SLD theory is more efficient than molecular simulation methods in determining the adsorbed CH4 density considering that only two parameters in the SLD model are adjusted to match the excess adsorption of CH4 on shale. It is observed that the corresponding absolute adsorption of CH4 is higher than the excess adsorption; this suggests that it is not reasonable to use the measured excess adsorption to estimate the storage of CH4 on shale. This study applies the SLD theory to investigate the adsorption behavior of CH4 in organic pores at different pressure/temperature conditions, and, more importantly, it yields a more-efficient approach (i.e., SLD theory) in determining the absolute adsorption than the sophisticated molecular simulations tools.

Potential hydrogen storage materials from metal decorated 2D-C2N: an ab initio study

2019 ◽  
Vol 21 (45) ◽  
pp. 25311-25322 ◽  
Author(s):  
R. Varunaa ◽  
P. Ravindran
Keyword(s):  
Binding Energy ◽  
Hydrogen Storage ◽  
Ab Initio ◽  
Mobile Applications ◽  
Ab Initio Study ◽  
Hydrogen Storage Materials ◽  
Storage Medium ◽  
Storage Materials

Mg decoration enhanced H2 binding energy in 2D-C2N and found to be a promising H2 storage medium for mobile applications.

Screening of Anti-mycobacterial Phytochemical Compounds for Potential Inhibitors against Mycobacterium Tuberculosis Isocitrate Lyase

2019 ◽  
Vol 19 (8) ◽  
pp. 600-608 ◽  
Author(s):  
Ashish Tiwari ◽  
Akhil Kumar ◽  
Gaurava Srivastava ◽  
Ashok Sharma
Keyword(s):  
Binding Energy ◽  
Virtual Screening ◽  
Md Simulation ◽  
Isocitrate Lyase ◽  
Docking Study ◽  
High Morbidity ◽  
Average Binding Energy ◽  
Ic50 Value ◽  
Key Enzyme ◽  
Potential Inhibitors

Conclusion:Phytochemical based anti-mycobacterial compound can further developed into effective drugs against persistence tuberculosis with lesser toxicity and side effects.Results:Docking and MD simulation studies of top hit compounds have identified shinjudilactone (quassinoid), lecheronol A (pimarane) and caniojane (diterpene) as potential MtbICL inhibitors.Methods:Virtual screening, molecular docking and MD simulation study has been integrated for screening of phytochemical based anti-mycobacterial compounds. Docking study of reported MtbICL inhibitors has shown an average binding affinity score -7.30 Kcal/mol. In virtual screening, compounds exhibiting lower binding energy than calculated average binding energy were selected as top hit compounds followed by calculation of drug likeness property. Relationship between experimental IC50 value and calculated binding gibbs free energy of reported inhibitors was also calculated through regression analysis to predict IC50 value of potential inhibitors.Background and Introduction:Tuberculosis (TB) is a leading infectious disease caused by Mycobacterium tuberculosiswith high morbidity and mortality. Isocitrate lyase (MtbICL), a key enzyme of glyoxylate pathway has been shown to be involved in mycobacterial persistence, is attractive drug target against persistent tuberculosis.

Hydrogen Storage in AB2 Laves Phase (A = Zr, Ti; B = Ni, Mn, Cr, V): Binding Energy and Electronic Structure

2010 ◽  
Vol 114 (39) ◽  
pp. 16832-16836 ◽  
Author(s):  
S. B. Gesari ◽  
M. E. Pronsato ◽  
A. Visintin ◽  
A. Juan
Keyword(s):  
Electronic Structure ◽  
Binding Energy ◽  
Hydrogen Storage ◽  
Laves Phase

Discovering the Mechanism of H2 Adsorption on Aromatic Carbon Nanostructures to Develop Adsorbents for Vehicular Applications

2004 ◽  
Vol 837 ◽  
Author(s):  
A. C. Dillon ◽  
J. L. Blackburn ◽  
P. A. Parilla ◽  
Y. Zhao ◽  
Y-H. Kim ◽  
...  
Keyword(s):  
Binding Energy ◽  
Hydrogen Storage ◽  
Carbon Nanostructures ◽  
Hydrogen Adsorption ◽  
Iron Catalyst ◽  
The United States ◽  
Department Of Energy ◽  
United States Department ◽  
Iron Particles ◽  
Aromatic Carbon

ABSTRACTHydrogen adsorption has been observed with a binding energy of ∼ 50 kJ /mol on as-synthesized carbon multi-wall nanotubes (MWNTs). The MWNTs are virtually free of non-nanotube carbon impurities but contain residual iron catalyst particles. The MWNTs are also highly graphitic. No hydrogen adsorption is observed at near ambient temperatures for purified MWNTs that are free of iron particles. However, hydrogen adsorption is also not observed on bare iron particles even following reduction in the presence of hydrogen at 775 K. These results imply that a special synergy occurs when small iron particles or atoms are in intimate contact with sp2-hybridized aromatic carbon. Interestingly, reducing the as-synthesized MWNTs in H2 at 573 K results in an increased hydrogen capacity. Understanding this hydrogen storage mechanism could facilitate the economical engineering of a hydrogen storage material that meets the United States Department of Energy targets for vehicular fuel cell applications. Recent theoretical studies have shown that an iron ad atom forms a complex with a C36 fullerene and shares charge with four carbon atoms of a bent five-membered ring. Three H2 ligands then coordinate with the iron forming a stable 18-electron organometallic complex. Here the binding energy of the molecular hydrogen ligands is ∼43 kJ /mol. These theoretical results could possibly explain the unique hydrogen storage properties of MWNTs that are grown with an iron catalyst.

Encapsulation of H2 Molecules in Cs3Na9-A Zeolite: A Theoretical Approach

2007 ◽  
Vol 124-126 ◽  
pp. 1657-1660
Author(s):  
Mee Kyung Song ◽  
Jung Sup Kim ◽  
Kyoung Tai No
Keyword(s):  
Activation Energy ◽  
Binding Energy ◽  
Theoretical Approach ◽  
Minimum Energy ◽  
Theoretical Method ◽  
Minimum Energy Path ◽  
Zeolite A ◽  
Average Binding Energy ◽  
Average Activation Energy

A theoretical method to study the encapsulation of H2 molecules in the cavities of Cs3Na9-A zeolite has been proposed. To study the properties of encapsulated H2 molecules, a Fermi-Dirac like statistics has been introduced. The average binding energy per H2 is obtained as a function of the number of molecules and temperature. The average activation energy is also calculated from the minimum energy path for the α- to α-cage transmission and the average binding energy. The fraction with higher energy than its activation energy has been calculated and revealed that the activation energy for the en- and decapsulation of H2 molecules depends not only on the temperature but also on the number of the encapsulated molecules.

scholarly journals First-Principles Study on Hydrogen Storage Performance of Transition Metal-Doped Zeolite Template Carbon

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 397 ◽  
Author(s):  
Han ◽  
Lv ◽  
Sun ◽  
Song
Keyword(s):  
Binding Energy ◽  
Transition Metal ◽  
Hydrogen Storage ◽  
First Principles ◽  
Hydrogen Adsorption ◽  
Storage Performance ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Metal Doped ◽  
Hydrogen Storage Performance

The hydrogen adsorption characteristics and mechanism of transition metal-doped zeolite template carbon (ZTC) as a novel porous material are studied by theoretical calculations employing first-principle all-electron atomic orbital method based on density functional theory. The stability of transition metal atoms (Sc, Ti, and V) decorated on zeolite template carbon is investigated by calculating the absorption binding energy. The adsorption configurations of the doped metal atom and adsorbed hydrogen are obtained from the energy functional minimization of first-principles calculations. The underlying mechanism for improving hydrogen storage performance of ZTC by doping transition metal atoms are explored through analyzing charge/spin populations of metal atoms in combination with the calculated results of hydrogen adsorption quantity and binding energy. To improve the hydrogen storage capability, the Sc, Ti, and V are individually introduced into the ZTC model according to the triplex axisymmetry. The hydrogen storage properties of ZTC decorated with different metal atoms are characterized by the adsorption energy and structure of several hydrogen atoms. The more energetically stable complex system with higher binding energy and adsorbing distance of hydrogen than lithium-doped ZTC can be achieved by doping Sc, Ti, V atoms in ZTC, which is expected to fulfill the substantial safe hydrogen storage by increasing hydrogen capacity with multi-sites doping of transition metal atoms. The present investigation provides a theoretical basis and predictions for the following experimental research and design of porous materials for hydrogen storage.

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