Hydrogen adsorption on magnesium-decorated (3, 3) and (5, 0) boron nitride nanotubes (original) (raw)
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Mg Decorated Boron doped Graphene for Hydrogen Storage: A DFT Method
International Journal for Research in Applied Science & Engineering Technology, 2020
First principles based DFT calculations performed to insight structural and electronic properties of Boron doped Magnesium atom decorated graphene sheet for application of hydrogen storage. The four H 2 molecules stably binds magnesium atom with Boron doped graphene sheet. The average binding energy extracted in the range-0.566 to-0.687 eV/H2.Partial density of states of complex system shows s and d orbitals of H 2 molecule and Mg atom at-0.1eV overlaps of main peaks indicates strong hybridizing and binding of s and d orbitals of H 2 and Mg atom respectively. HOMO & LUMO study shows stability of complex system. DOS investigation reveals the electronic density of states of complex system. I. INTRODUCTION In our daily life,there is a rapid increase in energy consumption to improve human development in terms of productivity and economic growth. Our goal is to replace the oil consumption by using new energy sources! The study of molecular hydrogen is alternative energy resource due to its vast applications in various fields [1-4]. Ensuring clean and efficient energy sources is one of the biggest challenges that we face in the 21 st century. With high energy conversion efficiency, zero pollutant emission, clean-burning product, rich in energy per unit mass, and most potentially abundant source, hydrogen energy is considered as the most clean and promising alternative energy source in the future [5]. To realize the Hydrogen Economy [6], the prime goal is investigating of safe, efficient and effective stores for H 2 gas, and replace current technologies based around the compression of H 2 as a liquid or as a gas using cryogenic. Recent, theoretical studies explained the poor capacity of H 2 adsorption on monolayer graphene surface. The theoretical results indicate, the adsorption energy (E ad) of H 2 on graphene sheets is approximately 5 kJ/mol [1], which is far from the recommended E ad (20-40 kJ/mol or 0.2-0.6 eV/Hydrogen molecule) for use of practical applications [7]. Therefore, enhanced adsorption energy of hydrogen on graphene could improve its uptake at room temperature [1]. Furthermore, theoretical results validate that a key factor leading to low H 2 adsorption capacity of pristine graphene [8] is weak binding between graphene sheets and H 2 atoms under ambient conditions. The decoration of graphene (Gr) sheets is considered as one of the promising methods for hydrogen uptake improvement at ambient temperature [9,10].Transition metals such as palladium (Pd) [11], calcium (Ca) [12] , The adsorption of hydrogen on boron doped graphene indicates the hydrogen storage capacity increases by doping the boron atom [13]. The study of PtH 2 systems absorbed on pristine and defective graphene explored the role of A van der Waals interaction[14], vanadium (V) [15], titanium (Ti) [16], nickel (Ni) [17], iron (Fe) [18] and Aluminium [19] can be useful for this purpose. The magnesium hydride considered as promising candidate for hydrogen storage materials due to its high hydrogen capacity [8],among these transition metals, palladium provides the best conditions for hydrogen storage due to high catalytic activity [8] and high affinity for hydrogen sorption [20]. Pd is five times cheaper than Pt and more electrochemically stable than other transition metal atoms such as Fe, Co and Ni [21]. To fulfill the demand of energy in vehicular system, one of the suitable way for production of renewable source such as hydrogen storage which is air pollution free promising candidate. We explored to achieve possibility of hydrogen storage for onboard application. In this study, for the first time a novel structure of graphene sheets as Mg-doped graphene sheets with boron in the presence of Mg atom was proposed to improve the hydrogen storage. This serves as the main novelty of this study. During hydrogen adsorption, boron can increase the adsorption of dissociated hydrogen atoms; their simultaneous application could be beneficial. Boron doping is a feasible and practical method to alter the binding structure and enhance the adsorption performance of hydrogen.
Retracted: Computational study of hydrogen adsorption on potassium-decorated boron nitride nanotubes
International Nano Letters
We have investigated the potassium-decorated boron nitride nanotubes for hydrogen storage using semi-empirical AM1 method. The ultra narrow (3,3) and (5,0) boron nitride nanotubes of same diameter but of different chirality have been used. Both of them show hydrogen storage greater than 8 % by weight. Density of states have been calculated, and it is found that the presence of alpha density of state of potassium results in smaller energy gap; as a result of which, the conductivity of the potassium-decorated boron nitride nanotubes is enhanced as compared to pristine boron nitride nanotubes. Charge decomposition analysis showed that there is significant transfer of charge from adsorbate potassium to boron nitride nanotubes; the same is also confirmed by Mulliken population analysis. For same diameter, due to different electronic configuration, zigzag tube is found to be slightly more favorable for hydrogen adsorption. The results of the present simulation study suggest that the potassiumdecorated boron nitride nanotubes are good candidate for hydrogen adsorption.
Mg decorated Boron doped Graphene for Hydrogen Storage
2020
First principles based DFT calculations performed to insight structural and electronic properties of Boron doped Magnesium atom decorated graphene sheet for application of hydrogen storage. The four H2 molecules stably binds magnesium atom with Boron doped graphene sheet. The average binding energy extracted in the range-0.566 to -0.687 eV/H2.Partial density of states of complex system shows s and d orbitals of H2 molecule and Mg atom at -0.1eV overlaps of main peaks indicates strong hybridizing and binding of s and d orbitals of H2 and Mg atom respectively. The gravimetric capacity of studied complex system reaching approximately 8.26 wt% hydrogen. HOMO & LUMO study shows stability of complex system.DOS investigation reveals the electronic density of states of complex system.
Oxygen-and Lithium-Doped Hybrid Boron-Nitride/Carbon Networks for Hydrogen Storage
Hydrogen storage capacities have been studied on newly designed three-dimensional pillared boron nitride (PBN) and pillared graphene boron nitride (PGBN). We propose these novel materials based on the covalent connection of BNNTs and graphene sheets, which enhance the surface and free volume for storage within the nanoma-terial and increase the gravimetric and volumetric hydrogen uptake capacities. Density functional theory and molecular dynamics simulations show that these lithium-and oxygen-doped pillared structures have improved gravimetric and volumetric hydrogen capacities at room temperature, with values on the order of 9.1−11.6 wt % and 40−60 g/L. Our findings demonstrate that the gravimetric uptake of oxygen-and lithium-doped PBN and PGBN has significantly enhanced the hydrogen sorption and desorption. Calculations for O-doped PGBN yield gravimetric hydrogen uptake capacities greater than 11.6 wt % at room temperature. This increased value is attributed to the pillared morphology, which improves the mechanical properties and increases porosity, as well as the high binding energy between oxygen and GBN. Our results suggest that hybrid carbon/BNNT nanostructures are an excellent candidate for hydrogen storage, owing to the combination of the electron mobility of graphene and the polarized nature of BN at heterojunctions, which enhances the uptake capacity, providing ample opportunities to further tune this hybrid material for efficient hydrogen storage.
The basic need for the survival and growth of living beings in this planet is energy. An uncontrolled usage of the fossil fuels in the various industrial sectors particularly in automobile industry has created panic regarding its availability in future. Dearth of fossil fuel reserves is alarming, as these underground resources are the prime reserves of energy other than the sun. The earth has been suffering from the dual curses of the greenhouse effect, caused due to environmental pollution, as well as shortage of fossil fuel reserves, caused due to excessive use of energy. Under these circumstances for the well-being of human beings scientists have being doing a lot of research on finding alternative sources of energy other than the natural fossil fuel reserves is of high importance. The use of hydrogen as an alternative source of energy is quiet important in this regard. Hydrogen is the third most abundant element on the earth , s surface, found everywhere -on the rocks, soils, air and obviously in water. Hydrogen demonstrates itself as one of the simplest chemical systems and upon combustion produces water as a harmless byproduct. Hydrogen has thus been conceived as a clean fuel source as against the oil and natural gas resources and unlike the latter, seldom pollutes the environment. Moreover, hydrogen has the highest energy density per kilogram in comparison with other combustible fuels, particularly natural gas. However, the use of hydrogen as a fuel source depends on its effective and safe means of storage. Hydrogen is extremely reactive in nature and therefore is not easy to control. It readily participates in combustion process. BN fullerene materials would store H 2 molecule easier than carbon fullerene materials, and its stability for high temperature would be good. The purpose of the present work is to investigate hydrogen gas storage and adsorption it on the BN nanocluster i.e. B 16 N 16 and B 24 N 24 , K + @B 16 N 16 and K + @B 24 N 24 by DFT/ M062X/6-311G (D, P) with Gaussian 09 software. We have calculated the HOMO-LUMO and Band gap and adsorption energy, Dipole moments and charge transfers. In the next stage we compare two these groups from the point view of adsorption energy. According to this work , it can be seen by placing K + within B 16 N 16 and B 24 N 24 nanofullerenes like structures , the adsorption energy is much than to the case where the K + cation is not. We have find the highest dipole moment and absorbed energy for H 2 /K + @B 16 N 16 among them. 2
JOURNAL OF ADVANCES IN PHYSICS, 2019
The influence of mechanical bending to tuning the hydrogen storage of Ni-functionalized of zigzag type of boron nitride nanotubes (BNNTs) has been investigated using density functional theory (DFT) with reference to the ultimate targets of the US Department of Energy (DOE). Single Ni atoms prefer to bind strongly at the axial bridge site of BN nanotube, and each Ni atom bound on BNNT may adsorb up to five, H2 molecules, with average adsorption energies per hydrogen molecule of )-1.622,-0.527 eV( for the undeformed B40N40-? = 0 , ) -1.62 , 0-0.308 eV( for the deformed B40N40-? = 15, ) -1.589, -0.310 eV( for the deformed B40N40-? = 30, and ) -1.368- -0.323 eV( for the deformed B40N40-? = 45 nanotubes respectively. with the H-H bonds between H2 molecules significantly elongated. The curvature attributed to the bending angle has effect on average adsorption energies per H2 molecule. With no metal clustering, the system gravimetric capacities are expected to be as large as 5.691 wt % f...
Carbon doped boron nitride cages as competitive candidates for hydrogen storage materials
Chemical Communications, 2010
By the incorporation of C atoms into (BN) 12 fullerene, our theoretical investigation shows that carbon doped boron nitride cages (BNC) can achieve a high hydrogen storage amount of 7.43 wt%, and dehydrogenation of the corresponding BNC hydrides (BNC H ) is thermodynamically favored for practical applications of hydrogen energy, making BNC competitive candidates for hydrogen storage materials.