Optimizing the hydrogen storage in boron nitride nanotubes by defect engineering (original) (raw)
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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...
Preparation and electrochemical hydrogen storage of boron nitride nanotubes
Boron nitride (BN) nanotubes were synthesized through chemical vapor deposition over a wafer made by a LaNi 5 /B mixture and nickel powder at 1473 K. Scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were performed to characterize the microstructure and composition of BN nanotubes. It was found that the obtained BN nanotubes were straight with a diameter of 30-50 nm and a length of up to several microns. We first verify that the BN nanotubes can storage hydrogen by means of an electrochemical method, though its capacity is low at present. The hydrogen desorption of nonelectrochemical recombination in cyclic voltammograms, which is considered as the slow reaction at BN nanotubes, suggests the possible existence of strong chemisorption of hydrogen, and it may lead to the lower discharge capacity of BN nanotubes. It is tentatively concluded that the improvement of the electrocatalytic activity by surface modification with metal or alloy would enhance the electrochemical hydrogen storage capacity of BN nanotubes.
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.
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
Hydrogen storage in boron substituted carbon nanotubes
Carbon, 2007
Template assisted synthesis of boron substituted carbon nanotubes was carried out by the carbonization of hydroborane polymer in alumina membrane template. The nanotubes were characterized by electron microscopic analysis, FT-Raman, FT-IR, XRD, X-ray photoelectron spectroscopy (XPS) and 13 C & 11 B MAS NMR techniques. The presence of boron in different chemical environment has been visualized by XPS and 11 B MAS NMR. The hydrogen absorption activity has been studied and a maximum of 2 wt% hydrogen storage capacity was observed.
Industrial & Engineering Chemistry Research
Boron nitride nanotubes (BNNT) were synthesized over both Fe3+ impregnated MCM-41 (mobil composition of matter no. 41) and Fe2O3/MCM-41 complex catalyst systems at relatively low temperatures for 1 h by the chemical vapor deposition technique in large quantities. The formation of BNNT was tailored at different reaction temperatures by changing catalyst type. The use of Fe3+-MCM-41 and Fe2O3 as a complex catalyst system led to thin and thick tube formations. The diameters of BNNTs were in the range of 2.5–4.0 nm for thin tubes and 20–60 nm for thick tubes. The thin tube formation originated from the growth of BNNT over Fe3+-MCM-41 due to its average pore size of 4 nm. Higher reaction temperatures caused both BNNT and iron-based side product formations. The hydrogen uptake capacity measurements by the Intelligent Gravimetric Analyzer at room temperature showed that BNNTs could adsorb 0.85 wt % hydrogen which was two times larger than that for commercial carbon nanotubes.
2005
We present a new reactive force field ReaxFF HBN derived to accurately model large molecular and condensed phase systems of H, B, and N atoms. ReaxFF HBN has been tested against quantum calculation data for B-H, B-B, and B-N bond dissociations and for H-B-H, B-N-B, and N-B-N bond angle strain energies of various molecular clusters. The accuracy of the developed ReaxFF HBN for B-N-H systems is also tested for ͑i͒ H-B and H-B bond energies as a function of out of plane in H-B͑NH 2 ͒ 3 and H-N͑BH 2 ͒ 3 , respectively, ͑ii͒ the reaction energy for the B 3 N 3 H 6 +H 2 → B 3 N 3 H 8 , and ͑iii͒ crystal properties such as lattice parameters and equations of states for the hexagonal type ͑h-BN͒ with a graphite structure and for the cubic type ͑c-BN͒ with a zinc-blende structure. For all these systems, ReaxFF HBN gives reliable results consistent with those from quantum calculations as it describes well bond breaking and formation in chemical processes and physical properties. Consequently, the molecular-dynamics simulation based on ReaxFF HBN is expected to give a good description of large systems ͑Ͼ2000 atoms even on the one-CPU machine͒ with hydrogen, boron, and nitrogen atoms.
The Journal of Chemical Physics, 2005
We present a new reactive force field ReaxFF HBN derived to accurately model large molecular and condensed phase systems of H, B, and N atoms. ReaxFF HBN has been tested against quantum calculation data for B-H, B-B, and B-N bond dissociations and for H-B-H, B-N-B, and N-B-N bond angle strain energies of various molecular clusters. The accuracy of the developed ReaxFF HBN for B-N-H systems is also tested for ͑i͒ H-B and H-B bond energies as a function of out of plane in H-B͑NH 2 ͒ 3 and H -N͑BH 2 ͒ 3 , respectively, ͑ii͒ the reaction energy for the B 3 N 3 H 6 +H 2 → B 3 N 3 H 8 , and ͑iii͒ crystal properties such as lattice parameters and equations of states for the hexagonal type ͑h-BN͒ with a graphite structure and for the cubic type ͑c-BN͒ with a zinc-blende structure. For all these systems, ReaxFF HBN gives reliable results consistent with those from quantum calculations as it describes well bond breaking and formation in chemical processes and physical properties. Consequently, the molecular-dynamics simulation based on ReaxFF HBN is expected to give a good description of large systems ͑Ͼ2000 atoms even on the one-CPU machine͒ with hydrogen, boron, and nitrogen atoms.