scholarly journals Adsorption-Based Hydrogen Storage in Activated Carbons and Model Carbon Structures

Reactions ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 209-226
Author(s):  
Anatoly Fomkin ◽  
Anatoly Pribylov ◽  
Ilya Men’shchikov ◽  
Andrey Shkolin ◽  
Oleg Aksyutin ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Adsorption ◽  
Activated Carbons ◽  
Carbon Adsorbent ◽  
Department Of Energy ◽  
Polymer Mixture ◽  
Adsorbed Hydrogen ◽  
Hydrogen Density ◽  
Carbon Structures ◽  
Temperature And Pressure

The experimental data on hydrogen adsorption on five nanoporous activated carbons (ACs) of various origins measured over the temperature range of 303–363 K and pressures up to 20 MPa were compared with the predictions of hydrogen density in the slit-like pores of model carbon structures calculated by the Dubinin theory of volume filling of micropores. The highest amount of adsorbed hydrogen was found for the AC sample (ACS) prepared from a polymer mixture by KOH thermochemical activation, characterized by a biporous structure: 11.0 mmol/g at 16 MPa and 303 K. The greatest volumetric capacity over the entire range of temperature and pressure was demonstrated by the densest carbon adsorbent prepared from silicon carbide. The calculations of hydrogen density in the slit-like model pores revealed that the optimal hydrogen storage depended on the pore size, temperature, and pressure. The hydrogen adsorption capacity of the model structures exceeded the US Department of Energy (DOE) target value of 6.5 wt.% starting from 200 K and 20 MPa, whereas the most efficient carbon adsorbent ACS could achieve 7.5 wt.% only at extremely low temperatures. The initial differential molar isosteric heats of hydrogen adsorption in the studied activated carbons were in the range of 2.8–14 kJ/mol and varied during adsorption in a manner specific for each adsorbent.

FIRST-PRINCIPLES STUDY OF Ti-CATALYZED HYDROGEN ADSORPTION ON LiB (001) SURFACE

2013 ◽  
Vol 12 (07) ◽  
pp. 1350065 ◽  
Author(s):  
WEIBIN ZHANG ◽  
AILING WU ◽  
YIDING LIU ◽  
SHAOLIN ZHANG ◽  
JIANHONG GONG ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
First Principles ◽  
Electronic Structures ◽  
Hydrogen Adsorption ◽  
Department Of Energy ◽  
Hydrogen Storage Material ◽  
Ambient Conditions ◽  
Storage Material ◽  
Practical Applications ◽  
Temperature And Pressure

Ti -doped LiB (001) is a promising material for hydrogen storage. The adsorption of H 2 is greatly enhanced by doping Ti into LiB (001), change the electronic structures of the surface Li , B atoms. After H 2 is adsorbed on the surface, the E ad of the ( H 2)n@ Ti / LiB (001) system is considered. It is around -0.22 eV/ H 2 to -0.31 eV/ H 2, which is close to the target specified by U.S. Department of Energy. The nature of the bonding between Ti and H 2 is due to the H 1s, Ti 4s and B 2s orbital hybridization. In addition, Ti 3d orbital is hybridized strongly with B -2p orbital, resulting in more stable Ti / LiB (001) system. These results are verified by the electron density distribution intuitively. It is found that the system can adsorb up to four H 2 at ambient temperature and pressure. Therefore, the Ti -doped LiB (001) would be a promising hydrogen storage material. Such optimal molecular hydrogen adsorption system makes H 2 adsorption feasible at ambient conditions, which is critical for practical applications.

scholarly journals Pinecone-Derived Activated Carbons as an Effective Medium for Hydrogen Storage

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2237
Author(s):  
Sara Stelitano ◽  
Giuseppe Conte ◽  
Alfonso Policicchio ◽  
Alfredo Aloise ◽  
Giovanni Desiderio ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Hydrogen Storage ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Textural Properties ◽  
Biomass Waste ◽  
Wavelength Dispersive Spectrometry

Pinecones, a common biomass waste, has an interesting composition in terms of cellulose and lignine content that makes them excellent precursors in various activated carbon production processes. The synthesized, nanostructured, activated carbon materials show textural properties, a high specific surface area, and a large volume of micropores, which are all features that make them suitable for various applications ranging from the purification of water to energy storage. Amongst them, a very interesting application is hydrogen storage. For this purpose, activated carbon from pinecones were prepared using chemical activation with different KOH/precursor ratios, and their hydrogen adsorption capacity was evaluated at liquid nitrogen temperatures (77 K) at pressures of up to 80 bar using a Sievert’s type volumetric apparatus. Regarding the comprehensive characterization of the samples’ textural properties, the measurement of the surface area was carried out using the Brunauer–Emmett–Teller method, the chemical composition was investigated using wavelength-dispersive spectrometry, and the topography and long-range order was estimated using scanning electron microscopy and X-ray diffraction, respectively. The hydrogen adsorption properties of the activated carbon samples were measured and then fitted using the Langmuir/ Töth isotherm model to estimate the adsorption capacity at higher pressures. The results showed that chemical activation induced the formation of an optimal pore size distribution for hydrogen adsorption centered at about 0.5 nm and the proportion of micropore volume was higher than 50%, which resulted in an adsorption capacity of 5.5 wt% at 77 K and 80 bar; this was an increase of as much as 150% relative to the one predicted by the Chahine rule.

scholarly journals The Storage of Hydrogen in Nanoporous Carbons

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Julio A. Alonso ◽  
Iván Cabria ◽  
María J. López
Keyword(s):  
Hydrogen Storage ◽  
Activated Carbons ◽  
Theoretical Work ◽  
Porous Carbons ◽  
Nanoporous Carbons ◽  
Hydrogen Molecules ◽  
Efficient Storage ◽  
Theoretical Predictions ◽  
Temperature And Pressure ◽  
Nanometric Size

An efficient storage of hydrogen is a crucial requirement for its use as a fuel in the cars of the future. Experimental and theoretical work has revealed that porous carbons are promising materials for storing molecular hydrogen, adsorbed on the surfaces of the pores. The microstructure of porous carbons is not well known, and we have investigated a class of porous carbons, the carbide-derived carbons, by computer simulation, showing that these materials exhibit a structure of connected pores of nanometric size, with graphitic-like walls. We then apply a thermodynamical model of hydrogen storage in planar and curved pores. The model accounts for the quantum effects of the motion of the molecules in the confining potential of the pores. The optimal pore sizes yielding the highest storage capacities depend mainly on the shape of the pore, and slightly on temperature and pressure. At 300 K and 10 MPa, the optimal widths of the pores lie in the range 6-10 Å. The theoretical predictions are consistent with experiments for activated carbons. The calculated storage capacities of those materials at room temperature fall below the targets. This is a consequence of an insufficiently strong attractive interaction between the hydrogen molecules and the walls of carbon pores. Recent work indicates the beneficial effect of metallic doping of the porous carbons in enhancing the binding energy of H<sub>2</sub> to the pore walls, and then the hydrogen storage.

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

Discovering the Mechanism of H2 Adsorption on Aromatic Carbon Nanostructures to Develop Adsorbents for Vehicular Applications

2004 ◽  
Vol 837 ◽  
Author(s):  
A. C. Dillon ◽  
J. L. Blackburn ◽  
P. A. Parilla ◽  
Y. Zhao ◽  
Y-H. Kim ◽  
...  
Keyword(s):  
Binding Energy ◽  
Hydrogen Storage ◽  
Carbon Nanostructures ◽  
Hydrogen Adsorption ◽  
Iron Catalyst ◽  
The United States ◽  
Department Of Energy ◽  
United States Department ◽  
Iron Particles ◽  
Aromatic Carbon

ABSTRACTHydrogen adsorption has been observed with a binding energy of ∼ 50 kJ /mol on as-synthesized carbon multi-wall nanotubes (MWNTs). The MWNTs are virtually free of non-nanotube carbon impurities but contain residual iron catalyst particles. The MWNTs are also highly graphitic. No hydrogen adsorption is observed at near ambient temperatures for purified MWNTs that are free of iron particles. However, hydrogen adsorption is also not observed on bare iron particles even following reduction in the presence of hydrogen at 775 K. These results imply that a special synergy occurs when small iron particles or atoms are in intimate contact with sp2-hybridized aromatic carbon. Interestingly, reducing the as-synthesized MWNTs in H2 at 573 K results in an increased hydrogen capacity. Understanding this hydrogen storage mechanism could facilitate the economical engineering of a hydrogen storage material that meets the United States Department of Energy targets for vehicular fuel cell applications. Recent theoretical studies have shown that an iron ad atom forms a complex with a C36 fullerene and shares charge with four carbon atoms of a bent five-membered ring. Three H2 ligands then coordinate with the iron forming a stable 18-electron organometallic complex. Here the binding energy of the molecular hydrogen ligands is ∼43 kJ /mol. These theoretical results could possibly explain the unique hydrogen storage properties of MWNTs that are grown with an iron catalyst.

The Synthesis of Nitrogen-Doped Mesoporous Carbon Spheres for Hydrogen Storage

2016 ◽  
Vol 852 ◽  
pp. 864-869 ◽  
Author(s):  
Zi Qiang Wang ◽  
Li Xian Sun ◽  
Fen Xu ◽  
Xiao Jun Peng
Keyword(s):  
Hydrogen Storage ◽  
Mesoporous Carbon ◽  
Hydrogen Adsorption ◽  
Activated Carbons ◽  
Phenol Formaldehyde ◽  
Carbon Sources ◽  
Soft Template ◽  
Carbon Spheres ◽  
High Nitrogen ◽  
Nitrogen Doped

The nitrogen-doped mesoporous carbon spheres have been synthesized via soft-template and hydrothermal synthetic strategies using phenol/formaldehyde resins as carbon sources and melamine as a nitrogen source. The obtained carbon spheres exhibit a spherical morphology with a size range of 3-5 μm, which possess the narrow microporosity (ca. 1.2 nm) and mesoporosity (ca. 4 nm), large surface area (560-1200 m2 g-1) and high nitrogen contents (up to 15.7 wt%). Due to the well-developed porous structure and high nitrogen content, the carbon spheres show high performance for hydrogen storage, and the hydrogen adsorption capacities are in the range of 140-185 cm3 g-1, which is better than that of most activated carbons. The incorporation of nitrogen into carbons is favored for hydrogen uptake in low pressure.

scholarly journals Hydrogen Adsorption in Carbon Materials

MRS Bulletin ◽  
1999 ◽  
Vol 24 (11) ◽  
pp. 45-50 ◽  
Author(s):  
M.S. Dresselhaus ◽  
K.A. Williams ◽  
P.C. Eklund
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Adsorption ◽  
Theoretical Calculations ◽  
Mass Density ◽  
Department Of Energy ◽  
Small Power ◽  
Adsorption Mechanisms ◽  
Graphite Nanofibers ◽  
Low Mass ◽  
Very High

Recent reports of very high, reversible adsorption of molecular hydrogen in pure nanotubes, alkali-doped graphite, and pure and alkali-doped graphite nanofibers (GNFs) have aroused tremendous interest in the research community, stimulating much experimental work and many theoretical calculations worldwide. The U.S. Department of Energy (DOE) Hydrogen Plan has seta standard for this discussion by providing a commercially significant benchmark for the amount of reversible hydrogen adsorption. This benchmark requires a system-weight efficiency (the ratio of stored H2 weight to system weight) of 6.5-wt% hydrogen and a volumetric density of 63 kg H2/m. If the encouraging experimental reports (summarized in Table I) are reproducible, it may be possible to reach the goals of the DOE Hydrogen Plan. On the other hand, the community still awaits confirmation of these experimental results by workers in other laboratories. Of additional concern is the fact that theoretical calculations have been unable to identify adsorption mechanisms compatible with the requirements of the DOE Hydrogen Plan.An economical, safe, hydrogen-storage medium is a critically needed component of a hydrogen-fueled transportation system. Hydrogen storage in a carbon-based material offers further advantages associated with its low mass density. Furthermore, fuel cell technology involving the conversion of hydrogen into protons, or hydrogen and oxygen into electric current, is being vigorously researched for both transportation and small power-plant applications.

scholarly journals Characterization of Carbon Materials for Hydrogen Storage and Compression

2020 ◽  
Vol 6 (3) ◽  
pp. 46
Author(s):  
Giuseppe Sdanghi ◽  
Rafael L. S. Canevesi ◽  
Alain Celzard ◽  
Matthias Thommes ◽  
Vanessa Fierro
Keyword(s):  
Hydrogen Storage ◽  
Surface Area ◽  
Density Functional ◽  
Carbon Materials ◽  
Hydrogen Adsorption ◽  
Activated Carbons ◽  
High Surface ◽  
Extensive Literature ◽  
Hydrogen Compression

Carbon materials have proven to be a suitable choice for hydrogen storage and, recently, for hydrogen compression. Their developed textural properties, such as large surface area and high microporosity, are essential features for hydrogen adsorption. In this work, we first review recent advances in the physisorption characterization of nanoporous carbon materials. Among them, approaches based on the density functional theory are considered now standard methods for obtaining a reliable assessment of the pore size distribution (PSD) over the whole range from narrow micropores to mesopores. Both a high surface area and ultramicropores (pore width < 0.7 nm) are needed to achieve significant hydrogen adsorption at pressures below 1 MPa and 77 K. However, due to the wide PSD typical of activated carbons, it follows from an extensive literature review that pressures above 3 MP are needed to reach maximum excess uptakes in the range of ca. 7 wt.%. Finally, we present the adsorption–desorption compression technology, allowing hydrogen to be compressed at 70 MPa by cooling/heating cycles between 77 and 298 K, and being an alternative to mechanical compressors. The cyclic, thermally driven hydrogen compression might open a new scenario within the vast field of hydrogen applications.

scholarly journals Chemical modification of the polymer of intrinsic microporosity PIM-1 for enhanced hydrogen storage

Adsorption ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 1083-1091
Author(s):  
Mi Tian ◽  
Sébastien Rochat ◽  
Hamish Fawcett ◽  
Andrew D. Burrows ◽  
Christopher R. Bowen ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Surface Area ◽  
Hydrogen Adsorption ◽  
Sorption Properties ◽  
Bet Surface Area ◽  
Polymer Modification ◽  
Gas Sorption ◽  
Chemically Modified ◽  
Polymer Of Intrinsic Microporosity ◽  
Intrinsic Microporosity

Abstract A detailed investigation has been carried out of the pre-polymerisation modification of the polymer of intrinsic microporosity PIM-1 by the addition of two methyl (Me) groups to its spirobisindane unit to create a new chemically modified PIM-1 analogue, termed MePIM. Our work explores the effects of this modification on the porosity of PIM-1 and hence on its gas sorption properties. MePIM was successfully synthesised using either low (338 K) or high (423 K) temperature syntheses. It was observed that introduction of methyl groups to the spirobisindane part of PIM-1 generates additional microporous spaces, which significantly increases both surface area and hydrogen storage capacity. The BET surface area (N2 at 77 K) was increased by ~ 12.5%, resulting in a ~ 25% increase of hydrogen adsorption after modification. MePIM also maintains the advantages of good processability and thermal stability. This work provides new insights on a facile polymer modification that enables enhanced gas sorption properties.

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