The nature, kinetics, and ultimate storage capacity of hydrogen sorption by carbon nanostructures

Nonorthogonal tight-binding model for hydrocarbons

“…The energy spectrum {ε n } is found from the solution of the stationary Schrödinger equation HΨ n (r) = ε n Ψ n (r) (4) by the expansion of eigenfunctions (5) in terms of the nonorthogonal atomic orbitals {ϕ iα (r)}, where i is the atomic number, α labels the type of atomic orbital (1S orbitals of hydrogen atoms and 2S, 2P x , 2P y , 2P z orbitals of carbon atoms are taken into account). Upon substitution of Eq.…”

“…The number of equations in the system (6) equals to the total number of atomic orbitals involved, i. e., N H + 4N C , where N H and N C is the number of hydrogen and carbon atoms respectively. Molecular orbitals (5) are occupied (according to the Fermi-Dirac distribution function and Pauli principle) by electrons, the number of which is N H + 4N C as well. Note that in the orthogonal tight-binding models, matrix S jβ iα is diagonal in (i, j) and (α, β).…”

“…In recent years, there was a growing interest in interaction between hydrogen (both atomic and molecular) and various carbon structures. This is in part due to the promising results of the first experiments on hydrogen absorption by carbon nanotubes [1,2,3] and a corresponding perspective to use hydrocarbons in hydrogen energetics, see reviews [4,5]. A solid based on clusters C 8 H 8 (cubanes) [6] is one more example of hydrocarbon systems important from both fundamental and practical viewpoints.…”

Compatibility of classical and quantum shortrange order descriptions in nanodimensional molecular systems

“…Some general regularities characteristic for gas sorption by different surface carbon structures have already been established [15,[19][20][21][22][23][24][25]. At the same time, thermodynamic conditions for the occurrence of physical and chemical sorption and their difference, sorption heat, estimates of the limiting capacitance characteristics, and methods of increasing composite stability have yet to be determined.…”

Comparing of Hydrogen On-Board Storage by the Largest Car Companies, Relevance to Prospects for More Efficient Technologies

“…For obtaining the project research results, the following will be used: 1) the unique technology of hydrogenation of carbon materials and nanomaterials in a gas at a pressure of molecular hydrogen up to 30 MPa and temperatures up to 870 K, as well as the technology of hydrogenation by superthermal hydrogen atoms; 2) methods of thermogravimetric analysis and thermal desorption analysis (with using the original developments [18] [19]) of hydrogenated materials and nanomaterials; 3) approaches and methods [14]- [19] of thermodynamic analysis of the experimental data obtained by the project participants, and comparison of the test results with the related theoretical and experimental data of other researchers to reveal the atomic mechanisms of the hydrogensorption and By using these methods, it will be determined the thermodynamic characteristics of hydrogen sorption (hydrogen concentrations, the equilibrium constants, the standard enthalpy changes, the activation volumes, the rate constants, the activation energies) and disclosed the atomic mechanisms of sorption for different hydrogen states in the expanded graphite (the first time) and graphene materials.…”