scholarly journals A Study on Electron Acceptor of Carbonaceous Materials for Highly Efficient Hydrogen Uptakes

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1524
Author(s):  
Seul-Yi Lee ◽  
Ji-Hye Park ◽  
Young-Jung Heo ◽  
Eun-Sang Lee ◽  
Soo-Jin Park
Keyword(s):  
Hydrogen Storage ◽  
Porous Carbon ◽  
Hydrogen Uptake ◽  
Department Of Energy ◽  
Carbon Surface ◽  
Carbonaceous Materials ◽  
Activation Temperature ◽  
Hydrogen Molecules ◽  
Environmental Pollution Problem ◽  
Underlying Mechanisms

Significant efforts have been directed toward the identification of carbonaceous materials that can be utilized for hydrogen uptake in order to develop on-board automotive systems with a gravimetric capacity of 5.5 wt.%, thus meeting the U.S. Department of Energy technical targets. However, the capacity of hydrogen storage is limited by the weak interaction between hydrogen molecules and the carbon surface. Cigarette butts, which are the most abundant form of primary plastic waste, remain an intractable environmental pollution problem. To transform this source of waste into a valuable adsorbent for hydrogen uptake, we prepared several forms of oxygen-rich cigarette butt-derived porous carbon (CGB-AC, with the activation temperature range of 600 and 900 °C). Our experimental investigation revealed that the specific surface area increased from 600 to 700 °C and then decreased as the temperature rose to 900 °C. In contrast, the oxygen contents gradually decreased with increasing activation temperature. CGB-AC700 had the highest H2 excess uptake () of 8.54 wt.% at 77 K and 20 bar, which was much higher than that of porous carbon reported in the previous studies. We found that the dynamic interaction between the porosity and the oxygen content determined the hydrogen storage capacity. The underlying mechanisms proposed in the present study would be useful in the design of efficient hydrogen storage because they explain the interaction between positive carbonaceous materials and negative hydrogen molecules in quadrupole orbitals.

scholarly journals Effect of Air Oxidation on Texture, Surface Properties and Dye Adsorption of Wood-Derived Porous Carbon Materials

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1675 ◽  
Author(s):  
Suhong Ren ◽  
Liping Deng ◽  
Bo Zhang ◽  
Yafang Lei ◽  
Haiqing Ren ◽  
...  
Keyword(s):  
Surface Area ◽  
Functional Groups ◽  
Porous Carbon ◽  
Carbon Materials ◽  
Dye Adsorption ◽  
Carbon Surface ◽  
Air Oxidation ◽  
Activation Temperature ◽  
Porous Carbon Materials ◽  
Hierarchical Porous

Hierarchical porous carbon materials made from cork were fabricated using a facile and green method combined with air activation, without any templates and chemical agents. The influence of air activation on the texture and other surface characteristics of the carbon materials were evaluated by various characterization techniques. Results indicate that air oxidation can effectively improve the surface area and the hierarchical porous structure of carbon materials, as well as increase the number of oxygen-containing functional groups on the carbon surface. The specific surface area and the pore volume of the carbon material activated by air at 450 °C (C800-M450) can reach 580 m2/g and 0.379 cm3/g, respectively. These values are considerably higher than those for the non-activated material (C800, 376 m2/g, 0.201 cm3/g). The contents of the functional groups (C–O, C=O and O–H) increased with rising activation temperature. After air activation, the adsorption capacity of the carbon materials for methylene blue (MB) and methyl orange (MO) was increased from 7.7 and 6.4 mg/g for C800 to 312.5 and 97.1 mg/g for C800-M450, respectively. The excellent dye removal of the materials suggests that the porous carbon obtained from biomass can be potentially used for wastewater treatment.

Lithium Decorated Borane Clusters (BnHnLi6, n=5-7) as Promising Materials for Hydrogen Storage: A Computational Study

2021 ◽  
Author(s):  
Shakti S Ray ◽  
Sridhar Sahu
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Md Simulations ◽  
Department Of Energy ◽  
Hydrogen Molecules ◽  
The Stability ◽  
Almost All

Abstract In this study, we have investigated the hydrogen adsorption potential of lithium decorated borane clusters (BnHnLi6, n = 5–7) using density functional theory calculations. The principle of maximum hardness and minimum electrophilicity confirmed the stability of the hydrogen adsorbed complexes. The outcomes of the study reveals that, the hydrogen molecules are adsorbed in a quasi-molecular fashion via Niu-Rao-Jena type of interaction with average adsorption energy falling in the range of 0.10-0.11eV/H2and average Li-H2 bond length is in the range of 2.436–2.550Å. It was found that the hydrogen molecules are physiosorbed at the host clusters at low temperature range 0K- 77K with gravimetric density up to 26.4 wt% which was well above target set by U.S. Department of Energy (US-DOE). ADMP-MD simulations showed that almost all the H2 molecules are desorbed at higher temperature form 373K-473K without distorting the host clusters which indicates the studied clusters can be promoted as promising reversible hydrogen storage

scholarly journals Hydrogen Storage in Iron/Carbon Nanopowder Composite Materials: Effect of Varying Spiked Iron Content on Hydrogen Adsorption

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chun-Lin Chu ◽  
Chia-Feng Chang ◽  
Jiann-Ruey Chen ◽  
Yiin-Kuen Fuh
Keyword(s):  
Composite Materials ◽  
Hydrogen Storage ◽  
Iron Content ◽  
Storage Capacity ◽  
Hydrogen Adsorption ◽  
Hydrogen Uptake ◽  
Uptake Capacity ◽  
Hydrogen Storage Capacity ◽  
Surface Areas ◽  
Hydrogen Molecules

This study investigates the effects of varying the spiked iron content of iron/carbon nanopowder (Fe/CNP) composite materials on hydrogen storage capacity. Among four such samples, a maximum hydrogen uptake of approximately 0.48 wt% was obtained with 14 wt% of spiked iron under 37 atm and 300 K. This higher hydrogen uptake capacity was believed to be closely related to the physisorption mechanism rather than chemisorption. In this case, the formation of maghemite catalyzed the attraction of hydrogen molecules and the CNP skeleton was the principal absorbent material for hydrogen storage. However, as the iron content exceeded 14 wt%, the formation of larger and poorly dispersed maghemite grains reduced the available surface areas of CNP for the storage of hydrogen molecules, leading to decreased uptake. Our study shows that hydrogen uptake capacities can be improved by appropriately adjusting the surface polarities of the CNP with well dispersed iron oxides crystals.

scholarly journals One-step chemical vapor deposition synthesis and supercapacitor performance of nitrogen-doped porous carbon–carbon nanotube hybrids

2017 ◽  
Vol 8 ◽  
pp. 2669-2679 ◽  
Author(s):  
Egor V Lobiak ◽  
Lyubov G Bulusheva ◽  
Ekaterina O Fedorovskaya ◽  
Yury V Shubin ◽  
Pavel E Plyusnin ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Hybrid Materials ◽  
Vapor Deposition ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Carbon Surface ◽  
Simultaneous Formation ◽  
Nitrogen Doped

Novel nitrogen-doped carbon hybrid materials consisting of multiwalled nanotubes and porous graphitic layers have been produced by chemical vapor deposition over magnesium-oxide-supported metal catalysts. CN x nanotubes were grown on Co/Mo, Ni/Mo, or Fe/Mo alloy nanoparticles, and MgO grains served as a template for the porous carbon. The simultaneous formation of morphologically different carbon structures was due to the slow activation of catalysts for the nanotube growth in a carbon-containing gas environment. An analysis of the obtained products by means of transmission electron microscopy, thermogravimetry and X-ray photoelectron spectroscopy methods revealed that the catalyst's composition influences the nanotube/porous carbon ratio and concentration of incorporated nitrogen. The hybrid materials were tested as electrodes in a 1M H2SO4 electrolyte and the best performance was found for a nitrogen-enriched material produced using the Fe/Mo catalyst. From the electrochemical impedance spectroscopy data, it was concluded that the nitrogen doping reduces the resistance at the carbon surface/electrolyte interface and the nanotubes permeating the porous carbon provide fast charge transport in the cell.

scholarly journals Mechanical bending effects on hydrogen storage of Ni decorated (8, 0) boron nitride nanotube : DFT study

2019 ◽  
Vol 16 (1) ◽  
pp. 299-325
Author(s):  
Atef Elmahdy ◽  
Hayam Taha ◽  
Mohamed Kamel ◽  
Menna Tarek
Keyword(s):  
Boron Nitride ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Boron Nitride Nanotubes ◽  
Department Of Energy ◽  
Functional Theory ◽  
Activation Barriers ◽  
The Us ◽  
Adsorption Energies ◽  
Mechanical Bending

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 % for 5H2 Ni B40N40-? = 0, 15, 30, 45. While the desorption activation barriers of the complexes nH2 + Ni B40N40-? = 0 (n = 1-4) are outside the (DOE) domain (-0.2 to -0.6 eV), the complexes nH2 + Ni- B40N40-? = 0 (n = 5) is inside this domain. For nH2 + Ni- B40N40-? = 15, 30, 45 with (n = 1-2) are outside the (DOE) domain, the complexes nH2 + Ni- B40N40-? = 15, 30, 45 with (n = 3-5) are inside this domain. The hydrogen storage of the irreversible 4H2+ Ni- B40N40-? = 0, 2H2+ Ni- B40N40-? = 15, 30, 45 and reversible 5H2+ Ni- B40N40-? = 0, 3H2+ Ni- B40N40-? = 15, 30, 45 interactions are characterized in terms of density of states, pairwise and non-pairwise additivity, infrared, Raman, electrophilicity and molecular electrostatic potentials. Our calculations expect that 5H2- Ni- B40N40-j = 0, 15, 30, 45 complexes are promising hydrogen storage candidates.

Nano-Columnar Mg Thin Films Created by Plasma Sputter Deposition for Improved Hydrogen Kinetics and Storage Properties

2004 ◽  
Vol 837 ◽  
Author(s):  
M. W. Zandbergen ◽  
S. W. H. Eijt ◽  
W. J. Legerstee ◽  
H. Schut ◽  
V. L. Svetchnikov
Keyword(s):  
Thin Films ◽  
Hydrogen Storage ◽  
Hydrogen Permeation ◽  
Hydrogen Desorption ◽  
Sputter Deposition ◽  
Hydrogen Molecules ◽  
Concomitant Reduction ◽  
And Storage ◽  
Determining Factor ◽  
Storage Properties

ABSTRACTThe hydrogen storage properties of nanostructured Mg and MgH2 thin films were studied as created by Ar and Ar+H2 plasma sputter deposition. Columnar structures with typical widths of ∼120 nm are observed with their long columnar axis extending throughout the thickness of the films. Applying substrate bias voltages during deposition results in narrower columns. A concomitant reduction in hydrogen desorption temperature from 400 °C to 360 °C is observed. Capping the Mg films with a ∼100 nm thin Pd layer leads to significantly reduced hydrogen desorption temperatures of ∼200 °C induced by the catalytic activity of the Pd cap layer. Also, hydrogen permeation of the films is strongly improved. The rate-determining factor is found to be the dissociation of the hydrogen molecules. Optimum hydrogen loading conditions of the Pd/Mg films were obtained just above ∼200 °C at hydrogen pressures of 0.25–1.0 MPa, resulting in hydrogen storage capacities in the range of 4–7 wt%.

Structural Characterization of ZnO/AC Composite Prepared from Spent Catalyst of Vinyl Acetate Synthesis

2012 ◽  
Vol 518-523 ◽  
pp. 3483-3487
Author(s):  
Wen Wen Qu ◽  
Wen Jin ◽  
Jin Hui Peng ◽  
Shu Yang
Keyword(s):  
Thermal Treatment ◽  
Vinyl Acetate ◽  
Operating Conditions ◽  
Carbon Surface ◽  
X Ray Diffraction ◽  
Spent Catalyst ◽  
Activation Temperature ◽  
Vinyl Acetate Synthesis ◽  
Ft Ir ◽  
Co2 Flow

ZnO/AC composite was prepared from spent catalyst of vinyl acetate synthesis by using conventional thermal treatment under CO2 atmosphere. The final composite was obtained with the operating conditions of activation temperature of 950°C, activation time of 120min and the CO2 flow rate of 600ml/min. The structure and surface properties of the ZnO/AC composite were observed and characterized by scanning electron microscope (SEM-EDX), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and the UV diffuse reflectance spectra. It was found that the zinc acetate present in the spent catalyst is transformed to zinc oxide (ZnO) after thermal treatment. ZnO particles were well adhered and uniformly distributed onto the carbon surface, forming ZnO/AC composite. The thermal treatment of the spent catalyst gives rise to a material with excellent adsorptive and photocatalytic properties.

First-Principles Study on the Hydrogen Storage of Sandwich-Type Dimetallocenes

2013 ◽  
Vol 677 ◽  
pp. 149-152
Author(s):  
Bo An ◽  
Hai Yan Zhu
Keyword(s):  
Hydrogen Storage ◽  
First Principles ◽  
Storage Capacity ◽  
High Capacity ◽  
First Principles Calculation ◽  
Hydrogen Storage Materials ◽  
Ambient Conditions ◽  
Hydrogen Storage Capacity ◽  
Hydrogen Molecules ◽  
Sandwich Type

The paper mainly focuses on the ability of absorbing hydrogen molecule of the dimetallocene (C5H5)2TM2(TM=Ti/Zn/Cu/Ni) based on the first-principles calculation. The result indicates that these compounds can adsorb up to eight hydrogen molecules, the binding energy is 0.596eV/H2 for Cp2Ti2, 0.802eV/H2 for Cp2Zn2, 0.422eV/H2 for Cp2Cu2 and 0.182eV/H2 for Cp2Ni2 respectively. The corresponding gravimetric hydrogen-storage capacity is 7.1wt% for Cp2Ti2, 6.2wt% for Cp2Zn2, 6.3wt% for Cp2Cu2 and 6.5wt% for Cp2Ni2 respectively. These sandwich-type organometallocenes proposed in this work are favorable for reversible adsorption and desorption of hydrogen under ambient conditions. These predictions will likely provide a new route for developing novel high-capacity hydrogen-storage materials.

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