The interaction of hydrogen with Li-coated C70 fullerene: A DFT study (original) (raw)
Related papers
A density functional study of hydrogen storage in Li decorated C20 fullerene
INTERNATIONAL CONFERENCE ON MULTIFUNCTIONAL MATERIALS (ICMM-2019)
Molecular adsorption of hydrogen in lithium decorated smallest fullerene (C 20 Li 2) has been carried out within the framework of density functional theory (DFT) at B3LYP/6311+G(d,p) level. Hydrogen molecules were added sequentially till maximum number of hydrogen molecules could be accommodate by the C 20 Li 2. The kinetic stabilities of the hydrogenated clusters were confirmed through global reactivity descriptors and electronic band gaps. It was observed that the C 20 Li 2 clusters could hold maximum up to eight hydrogen molecule with average adsorption energy in the range 0.11-0.06 eV/H 2 resulting in gravimetric density of 5.98 wt% which was in accordance with the target set by US Department of Energy (US-DOE) for optimal hydrogen adsorption. The average adsorption energy value and the distance between Li atom and hydrogen molecules indicated the process to be physisorption type. Topological analysis using Bader's quantum theory of atoms in molecules (QTAIM) concluded that the interaction between H 2 and Li atom to be closed shell type with ρ < 0.20 a.u with positive ∇ 2 ρ corresponding to ionic or van der Walls bonds.
A theoretical investigation of the interaction between H, Li, Na, K, and fullerenes
International Journal of Quantum Chemistry, 2005
We studied the interaction between H, Li, Na, and K with one and two C60 molecules using unrestricted Hartree-Fock (UHF) methods. We investigated the effects of distances between the doping atoms and the C60 clusters, total charges, interaction energies, stabilities, HOMO-LUMO energy differences, charge distribution, and potential energy surfaces. The effect of each doping atom was analyzed and potential technological applications discussed.
Li-doped fullerene structures: a molecular modelling study
Nanotechnology, 2005
Materials with exceptionally high contents of carbon are used in technologies with various degrees of added value, from quasi-amorphous materials for carbon electrodes used in e.g. lithium batteries to highly organized materials comprising e.g. nanotubes and fullerenes. The present study aims to test the feasibility of predicting the properties of carbon based materials using (i) molecular modelling and simulation techniques; (ii) application to fullerene as an idealized model of nano-pores in carbon materials; and (iii) available experimental data regarding the behaviour of carbon materials for lithium batteries as validation data. It has been found that the increase in the H/C atomic ratio has an ambivalent impact on the structural stability of lithium-doped carbon materials, with the ultimate lithium-doped material being the result of the 'tug of war' between the folding of the 'house-of-cards' structure due to increased flexibility of the idealized pore scaffold and the pore expansion due to the doping process coupled with the increase in structural flexibility. With regard to molecular motors, the simulations demonstrate that small numbers of hydrogenated defects may induce large enough structural changes to damage the smoothness of the surface of the nanogears, but the insertion of lithium atoms may stabilize this deleterious effect.
Influence of Electron Doping on the Hydrogenation of Fullerene C60: A Theoretical Investigation
ChemPhysChem, 2011
The influence of electron attachment on the stability of the mono- and dihydrogenated buckminsterfullerene C(60) was studied using density functional theory and semiempirical molecular orbital techniques. We have also assessed the reliability of computationally accessible methods that are important for investigating the reactivity of graphenic species and surfaces in general. The B3LYP and M06L functionals with the 6-311+G(d,p) basis set and MNDO/c are found to be the best methods for describing the electron affinities of C(60) and C(60)H(2) . It is shown that simple frontier molecular orbital analyses at both the AM1 and B3LYP/6-31G(d) levels are useful for predicting the most favourable position of protonation of C(60)H(-) , that is, formation of the kinetically controlled product 1,9-dihydro[60]fullerene, which is also the thermodynamically controlled product, in agreement with experimental and previous theoretical studies. We have shown that reduction of exo- and endo-C(60)H makes them more stable in contrast to the reduction of the exo,exo-1,9-C(60)H(2) , reduced forms of which decompose more readily, in agreement with experimental electrochemical studies. However, most other dihydro[60]fullerenes are stabilized by reduction and the regioselectivity of addition is predicted to decrease as the less stable isomers are stabilized more by the addition of electrons than the two most stable ones (1,9 and 1,7).
Journal of the American Chemical Society, 2010
Recent synthesis of the endohedral complexes of C 70 and its open-cage derivative with one and two H 2 molecules has opened the path for experimental and theoretical investigations of the unique dynamic, spectroscopic, and other properties of systems with multiple hydrogen molecules confined inside a nanoscale cavity. Here we report a rigorous theoretical study of the dynamics of the coupled translational and rotational motions of H 2 molecules in C 70 and C 60 , which are highly quantum mechanical. Diffusion Monte Carlo (DMC) calculations were performed for up to three para-H 2 (p-H 2 ) molecules encapsulated in C 70 and for one and two p-H 2 molecules inside C 60 . These calculations provide a quantitative description of the groundstate properties, energetics, and the translation-rotation (T-R) zero-point energies (ZPEs) of the nanoconfined p-H 2 molecules and of the spatial distribution of two p-H 2 molecules in the cavity of C 70 . The energy of the global minimum on the intermolecular potential energy surface (PES) is negative for one and two H 2 molecules in C 70 but has a high positive value when the third H 2 is added, implying that at most two H 2 molecules can be stabilized inside C 70 . By the same criterion, in the case of C 60 , only the endohedral complex with one H 2 molecule is energetically stable. Our results are consistent with the fact that recently both (H 2 ) n @C 70 (n ) 1, 2) and H 2 @C 60 were prepared, but not (H 2 ) 3 @C 70 or (H 2 ) 2 @C 60 . The ZPE of the coupled T-R motions, from the DMC calculations, grows rapidly with the number of caged p-H 2 molecules and is a significant fraction of the well depth of the intermolecular PES, 11% in the case of p-H 2 @C 70 and 52% for (p-H 2 ) 2 @C 70 . Consequently, the T-R ZPE represents a major component of the energetics of the encapsulated H 2 molecules. The inclusion of the ZPE nearly doubles the energy by which (p-H 2 ) 3 @C 70 is destabilized and increases by 66% the energetic destabilization of (p-H 2 ) 2 @C 60 . For these reasons, the T-R ZPE has to be calculated accurately and taken into account for reliable theoretical predictions regarding the stability of the endohedral fullerene complexes with hydrogen molecules and their maximum H 2 content.
First-principles study of hydrogen storage on Li12C60
Journal of the American Chemical Society, 2006
Solid state materials capable of storing hydrogen with high gravimetric (9 wt %) and volumetric density (70 g/L) are critical for the success of a new hydrogen economy. In addition, an ideal storage system should be able to operate under ambient thermodynamic conditions and exhibit fast hydrogen sorption kinetics. No materials are known that meet all these requirements. While recent theoretical efforts showed some promise for transition-metal-coated carbon fullerenes, later studies demonstrated that these metal atoms prefer to cluster on the fullerene surface, thus reducing greatly the weight percentage of stored hydrogen. Using density functional theory we show that Li-coated fullerenes do not suffer from this constraint. In particular, we find that an isolated Li 12C60 cluster where Li atoms are capped onto the pentagonal faces of the fullerene not only is very stable but also can store up to 120 hydrogen atoms in molecular form with a binding energy of 0.075 eV/H2. In addition, the structural integrity of Li12C60 clusters is maintained when they are allowed to interact with each other. The lowest energy structure of the dimer is one where the Li atom capped on the five-member ring of one fullerene binds to the six-member ring of the other. The binding of hydrogen to the linking Li atom and the potential of materials composed of Li12C60 building blocks for hydrogen storage are discussed.
Interaction of hydrogen with Pd- and co-decorated C24 fullerenes: Density functional theory study
Synthetic Metals, 2017
In this work, we have investigated the adsorption of a hydrogen atom and molecules on the Pd and Co-decorated C 24 fullerenes by means of density functional theory. The hydrogen interaction mechanism with host cages by regarding the adsorption energy and charge density variations was studied. It is found that both Pd and Co atoms have a significant role to increase the adsorption energy as an exothermal process. This energy change is strongly dependent on the electrostatic potential variations around the Pd and Co atoms doped on the C 24 fullerene. Also, the HOMO-LUMO gap (E g) for C 24 fullerene varies from 1.20 to 0.76 and 0.86 eV, after decorations of Co and Pd atoms, respectively. More consideration such as thermodynamics parameter, electronic density of states, and charge density analysis are discussed in the context.
2021
Diels-Alder cycloaddition reaction is helpful to produce covalent derivatives of fullerene with desirable electronic and physical properties. In the present venture, we have computationally investigated the reactivity of neutral C 60 and its Li + encapsulated derivative towards Multi-Diels-Alder (MDA) reaction with 1,3-butadiene, employing density functional theory (DFT). The computational reports available to date illustrate the functionalization of fullerene surfaces of neutral and encapsulated C 60 (Ca and Sm) with two butadiene molecules. In this article, we aim to investigate whether more than two butadiene molecules can be attached to the fullerene surface or not. To do so, we have shown that the MDA reaction initiates with the formation of an encounter complex between the mono-functionalized fullerene product and the second butadiene molecule. In this context, two different approaches, namely 'Direct' and 'Alternative' have been considered based on the attachment of the second butadiene, i.e., whether it is attached to the opposite or adjacent position of the first functionalization, which eventually produces the same final product. We have explored the MDA reactions by considering a total of four diene molecules that can be embedded successfully on the fullerene surface, with each reaction step having a high degree of exothermicity, thus making the overall reaction thermodynamically facile. In harmony with the mono-and bis-cycloaddition reactions, for MDA reaction also, the positive impact of Li + encapsulation for enhancing the reactivity of fullerene surface towards butadiene attachment is evident from our study. On-the-fly calculations also suggest the bond preference for [6, 6] connectivity than its [6, 5] counterpart, to be the suitable dienophile, just like the mono-and bis-functionalization reported earlier. Overall, the present study will foresee an extensive idea about the detailed mechanism of the MDA reaction on neutral C 60 and Li + @C 60 that could encourage the scientists to perform the aforementioned reaction for other fullerene derivatives in the long run.
Alkali-metal clusters encapsulated into fullerenes: Computations on Lix@C60
Journal of Computational Methods in Sciences and Engineering, 2008
Li@C60 and Li@C70 can be now produced by the low-energy bombardment method in bulk amounts and thus, their computations at higher levels of theory are also of interest. In the report, the computations are carried out on Li@C60, Li2@C60 and Li3@C60 with the B3LYP density-functional treatment in the standard 3-21G and 6-31G* basis sets. In all three species Li atoms exhibit non-central locations relatively close to the cage. The computed energetics suggests that Lix@C60 species could be produced for several small x values if the Li pressure is enhanced sufficiently. This type of metallofullerenes also belongs among potential candidate agents for nanoscience applications including molecular electronics.
Extending the hydrogen storage limit in fullerene
Carbon, 2017
Li 6 C 60 has been chosen as the most representative system to study the hydrogenation mechanism in alkali-cluster intercalated fullerides. We present here a muon spin relaxation (µSR) experiment that hints the chance to achieve a higher storage capacity on fullerene with respect to the values suggested in literature. Moreover, a linear relationship between the muonium adduct radical hyperfine frequency and the level of C 60 hydrogenation was found and it can be exploited to probe the C 60 hydrogenation level, giving more credit to this technique in the field of hydrogen storage materials.