共查询到20条相似文献,搜索用时 15 毫秒
1.
Nour F. Attia Mini M. Menemparabath Sivaram Arepalli Kurt E. Geckeler 《International Journal of Hydrogen Energy》2013
Inorganic nanotubes as a support material for polyaniline were used for hydrogen storage. To this end, a solid-state preparation method has been developed for controlling the hydrogen storage capacity of these nanocomposites. The hydrogen storage capacities have measured at room temperature and at a low pressure of 0.5 MPa using the precise quadrupole quartz crystal microbalance technique in a chamber free of moisture. The optimum nanocomposite shows an enhanced hydrogen storage capacity of 0.78 wt.% with excellent reversibility when compared to less than 0.019 wt.% capacity of the pristine nanotubes and 0.05 wt.% of polyaniline. This large increase in the hydrogen capacity can be attributed to the chemisorption hydrogen uptake, which was enhanced by the sorption sites created through the milling process of polyaniline with the nanotubes. This is in addition to the hydrogen adsorption contribution by a controlled lumen size that is suitable for a maximum hydrogen adsorption through inserting polyaniline chains into the nanotubes. 相似文献
2.
Gaofeng Zhao Yue Li Chunsheng Liu Yinliang Wang Jianmin Sun Yuzong Gu Yuanxu Wang Zhi Zeng 《International Journal of Hydrogen Energy》2012
By using first-principles methods, we perform a theoretical investigation of adsorption of hydrogen molecules between bilayer solid matrix layers (bilayer boron nitride sheets (BBN) and graphene/boron nitride heterobilayers (GBN)) with variable interlayer distance (ILD). We find that the H2 adsorption energy has a minimum by expanding the interlayer spacing, along with further interlayer expansion, arising from many H2 binding states and electrostatic interaction induced by the polar nature of B–N bonds. To determine if successive addition of H2 molecules is indeed possible using the minimal H2 adsorption energy as the reference state, we then simulate the hydrogen storage capacity of BBN and GBN with different stacking types, and find that the GBN with Bernal stacking is superior for reversible hydrogen storage. Up to eight H2 molecules can be adsorbed with the average adsorption energy of −0.20 eV/H2, corresponding to ∼7.69 wt % hydrogen uptake. 相似文献
3.
S. Seenithurai R. Kodi PandyanS. Vinodh Kumar C. SaranyaM. Mahendran 《International Journal of Hydrogen Energy》2014
Lithium decoration is an effective strategy for improving the hydrogen adsorption binding energy and the storage capacity in carbon nanostructures. Here, it is shown that Li-decorated double carbon vacancy graphene (DVG) can be used as an efficient hydrogen storage medium by means of Density Functional Theory (DFT) based calculations. The Li binding energy in DVG is 4.04 eV, which is much higher than that of pristine graphene. A maximum of four hydrogen molecules adsorb on Li decorated on one side of DVG and this leads to a gravimetric storage capacity of 3.89 wt% with an average adsorption binding energy of 0.23 eV/H2. When Li is decorated on both sides of DVG, the gravimetric storage capacity reaches 7.26 wt% with a binding energy of 0.26 eV/H2 which shows that desorption would take place at ambient conditions. 相似文献
4.
《International Journal of Hydrogen Energy》2021,46(71):35130-35136
Ab initio studies were conducted to evaluate the performance of hydrogen storage by Mg-decorated graphite carbon nitride (g-CN, heptazine structure). In our calculations, we found that each unit of this material can accommodate one Mg atom. Partial charges from Mg were transferred to the pristine material, making itself more electropositive. This is favorable for hydrogen storage, as the adsorbed H2 molecules can be easily polarized, and the electrostatic interactions can be enhanced. The configurations of the Mg-decorated g-CN with multiple adsorbed H2 molecules were presented in this study, and the related adsorption mechanisms were also discussed in details. Each unit can adsorb at most 7 H2 molecules with adsorption energies ranging from −0.276 eV to −0.130 eV. In addition, besides Mg, we also noticed that the nitrogen atoms also perform well in hydrogen adsorption. For this novel material, its highest capacity of hydrogen storage can reach to 7.8 wt%, highly surpassing the target value of 5.5 wt% set by the U.S. department of energy (DOE)[1]. The computational results provided in this study indicates a promising prospect for alkali metal functionalized 2D materials in energy storage; and through decent explorations, the performance of this class of materials can be largely improved. 相似文献
5.
《International Journal of Hydrogen Energy》2022,47(86):36605-36621
In this paper, we investigate the performance of large-sized single-walled carbon nanotubes (SWCNTs) incorporated with mono vacancy (MV), double vacancy (DV), and Stone-Wales (SW) topological defects as a medium for hydrogen adsorption using molecular dynamics (MD) simulations. A novel potential energy distribution (PED) method is employed with MD simulations to determine the adsorbed hydrogen molecules and associated binding energy. In addition, we extended our work to bundles of defected SWCNT (D-SWCNT) that provided the most prominent adsorption capacity subjected to temperature and pressure variations. In particular, four representative (8,8), (13,13), (19,19), and (33,0) SWCNTs are simulated under various thermodynamic conditions, and collected adsorption isotherms data reveals higher gravimetric density for large-sized SWCNT. At 77 K and 100 bar, the maximum hydrogen uptake in pristine SWCNTs is 6.88–7.73 wt%, depending on the size of the nanotubes. In contrast, the binding energy decreases as the nanotube size increases. At 77 K, (8,8) and (19,19) SWCNTs have average binding energies of 0.043 and 0.021 eV, respectively. Meanwhile, (19,19) SWCNT incorporated with 1% DV defects having 5–8 rings (DV1) and MV defects yields the maximum storage capacity of 9.07 wt% and 8.62 wt%, respectively, at 77 K. Furthermore, the increment of about 43.29% in wt.% is obtained for DV1 defected nanotube relative to pristine SWCNT at 300 K and 100 bar. Moreover, our results indicate the maximum hydrogen uptake of 8.65, 7.15, 2.57, and 1.33 wt% in the square array of DV1 defect embedded SWCNTs at 77, 100, 200, and 300 K, respectively, compared to 9.07, 6.65, 2.24, and 1.11 wt% in the isolated D-SWCNT at identical conditions. As a result, the D-SWCNT bundles are better suited for hydrogen storage at high temperatures than the isolated D-SWCNT. Our present study paves the way to progress toward the efficient usage of D-SWCNTs with few chemical alterations for scaled-up applications. 相似文献
6.
《International Journal of Hydrogen Energy》2022,47(99):41898-41910
With the aid of the state-of-the-art Density Functional Theory simulations, triazine-like graphitic carbon nitride or g-C3N4 (abbreviated as gCN hereafter) nanosheet decorated with Y has been explored for reversible hydrogen storage applications in light fuel cell vehicles. The Y atom is found to bind strongly with gCN (binding energy ~ ?6.85 eV), can reversibly store 9 H2 with an average adsorption energy of ?0.331 eV/H2, an average desorption temperature of 384.24 K, and a storage capacity of 8.55% by weight, optimum for fuel cell application as prescribed by the Department of Energy. The bonding of Y on gCN involves a charge transfer from Y 4d orbitals to C and N 2p orbitals, whereas the adsorption of H2 is due to Kubas interactions involving net charge transfer from Y 4d orbital to H 1s orbital. We have computed the diffusion energy barrier for Y atoms as 3.07 eV, which may prevent metal-metal clustering. Further, ab-initio molecular dynamics simulation has been performed to check the structural stability of the present system. The system is found to be stable at 500 K with different concentrations of Y doping. The present system with the appropriate average adsorption energy per H2, suitable desorption temperature, and structural stability at higher temperatures is promising for onboard light fuel cell applications. 相似文献
7.
《International Journal of Hydrogen Energy》2021,46(56):28700-28708
The mechanism of hydrogen molecule adsorption on 2D buckled bismuthene (b-Bi) monolayer decorated with alkali metal atoms was studied using density functional theory based first principles calculations. The decorated atoms Li, Na and K exhibited distribution on surface of b-Bi monolayer with increasing binding energy of 2.6 eV, 2.9 eV and 3.6 eV respectively. The adsorption of H2 molecule on the slabs appeared stable which was further improved upon inclusion of van der Waals interactions. The adsorption behaviour of H2 molecules on the decorated slabs is physisorption whereas the slabs were able to bind up to five H2 molecules. The average adsorption energy per H2 molecules are in range of 0.1–0.2 eV which is good for practical applications. The molecular dynamics simulation also confirmed the thermodynamic stabilities of five H2 molecules adsorbed on the decorated slabs. The storage capacity values are found 2.24 wt %, 2.1 wt %, and 2 wt %, for respective cases of Li, Na and K atoms decorated b-Bi. The analysis of the adsorbed cases pointed to electrostatic interaction of Li and H2 molecule. The adsorption energies, binding energies, charge analysis, structural stability, density of states, and hydrogen adsorption percentage specifies that the decorated b-Bi may serve as an efficient hydrogen storage material and could be an effective medium to interact with hydrogen molecules at room temperature. 相似文献
8.
Based on ab initio calculations, we investigated the hydrogen storage capacity of Li decorated 6,6,12-graphyne (Li@GY). Due to the unique sp hybridization in GY, Li atoms can strongly bind to carbon atoms to avoid the formation of Li clusters on the surface of GY. It is found that the hydrogen storage capacity of Li@GY is high up to 19.3 wt% with the average adsorption energy of −0.230 eV which lying in the ideal adsorption energy range for practical application of hydrogen economy. The density of states and charge density difference demonstrated that the adsorption mechanism mainly depended on the electrostatic field produced by the Li ions on GY. Moreover, the formation of super hydrogen molecules induced by the electrostatic field around Li ions can further enhance the hydrogen absorption energy. Our results indicated that Li decorated 6,6,12-graphyne would be a potential material for hydrogen storage. 相似文献
9.
Mingmin Shi Qiang Wu Xin Huang Zhaoshun Meng Yunhui Wang Zhihong Yang Jing Hu Yi Xu Huaihong Zhao Gang Yan 《International Journal of Hydrogen Energy》2021,46(42):21965-21972
To find ideal hydrogen storage media, hydrogen storage performance of Li decorated net-τ has been investigated by first-principles calculations. Maximum 6 Li atoms are adsorbed on net-τ, with the average binding energy of 2.15 eV for per Li atom. Based on 6Li-decorated net-τ, up to twenty H2 molecules are adsorbed, with a high H2 storage capacity of 12.52 wt% and an appropriate adsorption energy of 0.21 eV/H2. Finally, H2 uptake performance is measured by GCMC simulations. Our results suggest that Li-decorated net-τ may be a promising hydrogen storage medium under realistic conditions. 相似文献
10.
《International Journal of Hydrogen Energy》2022,47(80):34183-34194
The development of advanced materials for the safety and efficiency of hydrogen storage media is necessary. We computationally explored the hydrogen storage properties of penta-CN2 sheet. The hydrogen adsorption properties of neutral, negatively charged, externally strained, and metal-doped penta-CN2 sheets were investigated in detail. Here, for the first time, the effect of the strain of two-dimensional nonmetallic materials on hydrogen adsorption is investigated. We found that the hydrogen binding energy increases to ?0.20 eV and achieves storage capacities up to 9.00 wt % on the negatively charged substrate, and to ?0.14 eV at 18% stretching. Moreover, metal doping causes hydrogen adsorption energy to increase to ?0.25–0.82 eV. The hydrogen storage capacity of Li-doped defective CN2 sheet is up to 10.90 wt%. Our study may provide new insights into the search for advanced materials for reversible hydrogen storage. 相似文献
11.
Peng Gao Ji-wen Li Jie Zhang Guangzhao Wang 《International Journal of Hydrogen Energy》2021,46(42):21739-21747
Density functional theory (DFT) computational studies were conducted to explore the hydrogen storage performance of a monolayer material that is built on the base of carbon nitride (g-C3N4, heptazine structure) with decoration by magnesium (Mg). We found that a 2 × 2 supercell can bind with four Mg atoms. The electronic charges of Mg atoms were transferred to the g-C3N4 monolayer, and thus a partial electropositivity on each adsorbed Mg atom was formed, indicating a potential improvement in conductivity. This subsequently causes the hydrogen molecules’ polarization, so that these hydrogen molecules can be efficiently adsorbed via both van der Waals and electrostatic interactions. To note, the configurations of the adsorbed hydrogen molecules were also elucidated, and we found that most adsorbed hydrogen molecules tend to be vertical to the sheet plane. Such a phenomenon is due to the electronic potential distribution. In average, each adsorbed Mg atom can adsorb 1–9 hydrogen molecules with adsorption energies that are ranged from ?0.25 eV to ?0.1 eV. Moreover, we realised that the nitrogen atom can also serve as an active site for hydrogen adsorption. The hydrogen storage capacity of this Mg-decorated g-C3N4 is close to 7.96 wt %, which is much higher than the target value of 5.5 wt % proposed by the U.S. department of energy (DOE) in 2020 [1]. The finding in this study indicates a promising carbon-based material for energy storage, and in the future, we hope to develop more advanced materials along this direction. 相似文献
12.
《International Journal of Hydrogen Energy》2019,44(10):4907-4918
Different sites for K adsorption in γ-graphyne were investigated using density functional theory (DFT) calculations and optical and structural properties of the structures were examined. For the most stable structures, we put one H2 molecule in different directions on the various sites to evaluate the hydrogen adsorption capability of them. Then, one to nine H2 molecules in sequence were added to the best structure. Results show that clustering of the K atoms is hindered on the graphyne surface and the most desirable adsorption site for K atom is the hollow site of 12-membered ring with adsorption energy of 5.86 eV. Also, this site is the best site for H2 adsorption onto K-decorated graphyne with Edas of −0.212 eV. Adding of number of H2 molecule on this site shows that K atom can bind nine H2 molecules at one side of the graphyne with the average adsorption energy of 0.204 eV/H2. Therefore, for one side ca. 8.95 wt % and for both sides of the graphyne with a K atom in each side ca. 13.95 wt % of the hydrogen storage capacity can be achieved. This study shows that K-decorated graphyne can be a promising candidate for the hydrogen storage applications. 相似文献
13.
W.-C. Xu K. Takahashi Y. Matsuo Y. Hattori M. Kumagai S. Ishiyama K. Kaneko S. Iijima 《International Journal of Hydrogen Energy》2007
Hydrogen storage capacity of various carbon materials, including activated carbon (AC), single-walled carbon nanohorn, single-walled carbon nanotubes, and graphitic carbon nanofibers, was investigated at 303 and 77 K, respectively. The results showed that hydrogen storage capacity of carbon materials was less than 1 wt% at 303 K, and a super activated carbon, Maxsorb, had the highest capacity (0.67 wt%). By lowering adsorption temperature to 77 K, hydrogen storage capacity of carbon materials increased significantly and Maxsorb could store a large amount of hydrogen (5.7 wt%) at a relatively low pressure of 3 MPa. Hydrogen storage capacity of carbon materials was proportional to their specific surface area and the volume of micropores, and the narrow micropores was preferred to adsorption of hydrogen, indicating that all carbon materials adsorbed hydrogen gas through physical adsorption on the surface. 相似文献
14.
《International Journal of Hydrogen Energy》2022,47(61):25696-25703
In this work, we report on the study of the hydrogen storage capability of titanium (Ti) decorated B36 nanosheets using density functional theory (DFT) calculations with van der Waals corrections. Ti atoms are strongly bonded to the surface of B36 with a binding energy of 6.23 eV, which exceeds the bulk cohesive energy of crystalline Ti. Ti-decorated B36 (2Ti@B36) can reversibly adsorb up to 12 H2 molecules with a hydrogen storage capacity of 4.75 wt % and average adsorption energy between 0.361 and 0.674 eV/H2. The values of desorption temperature and the results of molecular dynamics simulations enable to conclude that 2Ti@B36 is a perspective reversible material for hydrogen storage under real conditions. 相似文献
15.
E. Rangel J.M. Ramírez-Arellano I. Carrillo L.F. Magana 《International Journal of Hydrogen Energy》2011,36(21):13657-13662
Density functional theory and molecular dynamics were used to study the interaction of a lithium atom with a vacancy inside a graphene layer. It was found that the lithium atom is adsorbed on this vacancy, with a binding energy much larger than the lithium cohesive energy. Then, the adsorption of hydrogen molecules around lithium atoms was studied. We found that at 300 K and atmospheric pressure, this system could store up to 6.2 wt.% hydrogen, with average adsorption energy of 0.19 eV per molecule. Thus, this material satisfies the gravimetric capacity requirements for technological applications. A complete desorption of hydrogen occurs at 750 K. However, a multilayer of this system would be required for practical reasons. Under atmospheric pressure and at 300 K, we found that a system made of multiple layers of this material is stable. The storage capacity remained at 6.2 wt.%, but all adsorbed molecules were dissociated. The average adsorption energy becomes 0.875 eV/H. 相似文献
16.
《International Journal of Hydrogen Energy》2023,48(20):7400-7418
The hydrogen storage capacity of M-decorated (M = Li and B) 2D beryllium hydride is investigated using first-principles calculations based on density functional theory. The Li and B atoms were calculated to be successfully and chemically decorated on the Surface of the α-BeH2 monolayer with a large binding energy of 2.41 and 4.45eV/atom. The absolute value was higher than the cohesive energy of Li and B bulk (1.68, 5.81eV/atom). Hence, the Li and B atoms are strongly bound on the beryllium hydride monolayer without clustering. Our findings show that the hydrogen molecule interacted weakly with B/α-BeH2(B-decorated beryllium hydride monolayer) with a low adsorption energy of only 0.0226 eV/H2 but was strongly adsorbed on the introduced active site of the Li atom in the decorated BeH2 with an improved adsorption energy of 0.472 eV/H2. Based on density functional theory, the gravimetric density of 28H2/8li/α-BeH2) could reach 14.5 wt.% higher than DOE's target of 6.5 wt. % (the criteria of the United States Department of Energy). Therefore, our research indicates that the Li-decorated beryllium hydride monolayer could be a candidate for further investigation as an alternative material for hydrogen storage. 相似文献
17.
《International Journal of Hydrogen Energy》2020,45(19):11176-11189
Hydrogen storage remains a largely unsolved problem facing the green energy revolution. One approach is physisorption on very high surface area materials incorporating metal atoms. Boron nitride nanotubes (BNNTs) are a promising material for this application as their behaviour is largely independent of the nanoscopic physical features providing a greater degree of tolerance in their synthesis. Aluminum doping has been shown to be a promising approach for carbon nanotubes but has been underexplored for BNNTs. Using first principles density functional theory, the energetics, electronics and structural impacts of aluminum adsorption to both zigzag and armchair polymorphs of BNNTs was investigated along with their potential capacity to adsorb hydrogen. The fine atomic structural and electronic details of these interactions is discussed. We predicted that in an ideal situation, highly aluminum-doped armchair and zigzag BNNTs could adsorb up to 9.4 and 8.6 wt percent hydrogen, well above the United States Department of Energy targets marking these as promising materials worthy of further study. 相似文献
18.
19.
Qianku Hu Haiyan Wang Qinghua Wu Xiaotao Ye Aiguo Zhou Dandan Sun Libo Wang Baozhong Liu Julong He 《International Journal of Hydrogen Energy》2014
Recently, a new family of two-dimensional (2D) MXene materials was prepared by exfoliating the MAX phases (ACS Nano 2012, 6, 1322). Among all possible MXene phases, theoretically 2D Sc2C possesses the highest surface area per weight and thus is expected to have the highest gravimetric hydrogen storage capacities. In this work, using first-principles total energy pseudopotential calculations, we systematically investigated the hydrogen storage properties of 2D Sc2C phase. Depending on different adsorption sites, the hydrogens are bound by three modes: chemisorption, physisorption and Kubas-type interactions with the binding energies of 4.703, 0.087 and 0.164 eV respectively. The maximum hydrogen storage capacity was calculated to be 9.0 wt.%, which meets the gravimetric storage capacity target (5.5 wt.% by 2015) set by the U.S. DOE. Ab-initio molecular dynamic simulations confirmed that 3.6 wt.% hydrogen molecules storaged by Kubas-type interactions can be adsorbed and released reversibly at ambient conditions. 相似文献
20.
《International Journal of Hydrogen Energy》2020,45(60):34949-34955
Hydrogen storage is still one of the most important problems to improve hydrogen energy usage widespread. New materials capable of storing hydrogen with high efficiency must be introduced to overcome this problem. In recent years, addition of metals or inorganic compounds to multiwalled carbon nanotubes (MWCNTs) has been generally used for hydrogen uptake studies to enhance adsorption property of the nanotubes. In this study, Zinc oxide (ZnO) nanoparticles doped MWCNTs (ZnO-MWCNTs) have been produced as new reversible hydrogen storage materials, and we have investigated characterization of ZnO-MWCNTs by XRD, SEM, TGA, TEM and BET analyses. The functionalized MWCNTs and ZnO doped MWCNTs were subjected to hydrogenation step by dynamic gas sorption analyser under pressure of 5–50 bar. The hydrogen uptake capacities of the materials under different pressures were measured gravimetrically. It was indicated that by controlling the pressures for hydrogenation of ZnO-MWCNTs induces the spillover of ZnO nanoparticles in the layer of MWCNTs which in return with high hydrogen adsorption capacity. Consequently, the hydrogen adsorption of the functionalized MWCNTs (f-MWCNTs) and the ZnO-MWCNTs were achieved to be 1.05 wt% and 2.7091 wt% under pressure of 50 bar as maximum. 相似文献