Storage of hydrogen in nanostructured carbon materials

Energy Storage, 2019

It is well known that three challenges of hydrogen economy, that is, production, storage, and transportation or application put tremendous stress on scientific community for the past several decades. Based on several investigations, reported in literature, it is observed that the storage of hydrogen in solid form is more suitable option to overcome the challenges like its storage and transportation. In this form, hydrogen can be stored by absorption (metal hydrides and complex hydrides) and adsorption (carbon materials). Compared to absorption, adsorption of hydrogen on carbon materials is observed to be more favorable in terms of storage capacity. Taking in to account of these facts, in this short review, an overview on hydrogen adsorption on activated carbon and different allotropes of carbon like graphite, carbon nanotubes, and carbon nanofibers is presented. Synthesis processes of all the carbon materials are discussed in brief along with their hydrogen storage capacities at different operating conditions, and thermodynamic properties and reaction kinetics. In addition, different methods to improve hydrogen storage capacities of carbon materials are presented in detail. Finally, comparison is made between different carbon materials to estimate the amount of hydrogen that can be stored and retract practically. The experimentally measured maximum hydrogen storage capacity of activate carbon, graphite, single-walled nanotubes, multiwalled nanotubes, and carbon nanofibers at room temperature are 5.5 wt%, 4.48 wt%, 4.5 wt %, 6.3 wt%, and 6.5 wt%, respectively.

Journal of Alloys and Compounds, 2002

The paper gives a critical review of the literature on hydrogen storage in carbon nanostructures. Furthermore, the hydrogen storage of graphite, graphite nanofibers (GNFs), and single-walled carbon nanotubes (SWNTs) was measured by thermal desorption spectroscopy (TDS). The samples were ball milled under Ar or D atmosphere in order to modify the microstructure which was characterized by X-ray 2 diffraction, scanning electron microscopy, and transmission electron microscopy. These investigations show a reversible hydrogen storage only for SWNTs and in addition indicate that an opening of the SWNTs is essential to reach high storage capacities.

Journal of Alloys and Compounds, 2003

Literature data on the storage capacities of hydrogen in carbon nanostructures show a scatter over several orders of magnitude which cannot be solely explained by the limited quantity or purity of these novel nanoscale materials. With this in mind, this article revisits important experiments. Thermal desorption spectroscopy as a quantitative tool to measure the hydrogen storage capacity needs an appropriate calibration using a suitable hydride. Single-walled carbon nanotubes that have been treated by ultra-sonication show hydrogen uptake at room temperature. However, this storage can be assigned to metal particles incorporated during the sonication treatment. Reactive high-energy ball milling of graphite leads to a high hydrogen loading, however the temperatures for hydrogen release are far too high for application. In view of today's knowledge, which is mainly based on experiments with small quantities and poorly characterised samples, carbon nanostructures at around room temperature cannot store the amount of hydrogen required for automotive applications. 

Advanced Materials, 2011

The outstanding ability of carbon to form a variety of structures (graphite, diamond, lonsdaleite, fullerenes, nanotubes etc .) with quite different physical properties stimulated a lot of work on carbon-based materials in the last decades. To mention a few actively developing fi elds, we note the search for superhard materials, materials with valuable transport properties, and hydrogen storage media. Many hypothetical as well as experimentally characterized carbon materials with promising mechanical, electronic or transport properties are known. On the contrary, carbon-based materials proposed so far as hydrogen storage media (graphite intercalated with fullerenes, carbon foams, nanotube bundles, etc.) show quite moderate performance. [ 7a ] Hydrogen uptake of such materials [ 6 , 7b ] usually amounts up to ∼ 3.0-7.0 wt.% at 77 K which is quite far from the target value set by the US Department of Energy (6 wt.% at nearly ambient conditions) and makes carbon materials poor candidates for hydrogen storage applications. As a result, nowadays the research focus is shifted to other materials such as metal-organic frameworks (MOFs) or covalent-organic frameworks (COFs) which allow for much higher storage capacities and are capable of easy chemical functionalization. In this communication we show that the potential of carbon materials is far from being exhausted and propose for the fi rst time energetically and mechanically stable packings of carbon nanotubes with outstanding hydrogen storage capacities.

Hydrogen is an ideal fuel, which provides the best route to a sustainable energy with high utilization efficiency. The US Department of Energy (DOE) has set a standard for the amount of reversible hydrogen adsorption as system-weight efficiency (the ratio of stored hydrogen weight to system weight) of 6.5-wt % of hydrogen and a volumetric density of 62 kg H 2 /m 3 . Nanostructured carbon materials are considered to be the potential material for hydrogen storage. In this article the methods of synthesis of carbon nanotubes and their hydrogen uptake behaviour have been discussed. He has worked on amorphous carbon, carbon-carbon composite, carbon nanomaterials and silicon carbide coating by CVD method. He has developed flow sheet for making novel amorphous carbon-carbon composites and TRISO coated fuel particles useful for advanced nuclear reactors. He has experience in synthesis and characterization of carbon nanotubes using different techniques like catalytic chemical vapour deposition, spray pyrolysis and fluidized bed method. Presently he is developing carbon nanotube based composites to be used for water purification and hydrogen adsorption. Shri Dasgupta, life members of Indian Institute of Metals and Indian Carbon Society has authored more than 35 scientific articles in refereed journals and conference proceedings.

Studies in Surface Science and Catalysis, 2007

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 2 to the pore walls, and then the hydrogen storage.

Carbon, 2007

Hydrogen adsorption measurements have been carried out at different temperatures (298 K and 77 K) and high pressure on a series of chemically activated carbons with a wide range of porosities and also on other types of carbon materials, such as activated carbon fibers, carbon nanotubes and carbon nanofibers. This paper provides a useful interpretation of hydrogen adsorption data according to the porosity of the materials and to the adsorption conditions, using the fundamentals of adsorption. At 298 K, the hydrogen adsorption capacity depends on both the micropore volume and the micropore size distribution. Values of hydrogen adsorption capacities at 298 K of 1.2 wt.% and 2.7 wt.% have been obtained at 20 MPa and 50 MPa, respectively, for a chemically activated carbon. At 77 K, hydrogen adsorption depends on the surface area and the total micropore volume of the activated carbon. Hydrogen adsorption capacity of 5.6 wt.% at 4 MPa and 77 K have been reached by a chemically activated carbon. The total hydrogen storage on the best activated carbon at 298 K is 16.7 g H 2 /l and 37.2 g H 2 /l at 20 MPa and 50 MPa, respectively (which correspond to 3.2 wt.% and 6.8 wt.%, excluding the tank weight) and 38.8 g H 2 /l at 77 K and 4 MPa (8 wt.% excluding the tank weight).

2013

Hydrogen fuel is a zero-emission fuel which uses electrochemical cells or combustion in internal engines, to power vehicles and electric devices. Methods of hydrogen storage for subsequent use span many approaches, including high pressures, cryogenics and chemical compounds that reversibly release H<sub>2</sub> upon heating. Most research into hydrogen storage is focused on storing hydrogen as a lightweight, compact energy carrier for mobile applications. With the accelerating demand for cleaner and more efficient energy sources, hydrogen research has attracted more attention in the scientific community. Until now, full implementation of a hydrogen-based energy system has been hindered in part by the challenge of storing hydrogen gas, especially onboard an automobile. New techniques being researched may soon make hydrogen storage more compact, safe and efficient. In this overview, few hydrogen storage methods and mechanism of hydrogen uptake in carbon nanotubes are summa...

International Journal of Hydrogen Energy, 2012

Spillover effect Functionalized groups Surface area a b s t r a c t The hydrogen adsorption capacity of different types of carbon nanofibers (Platelet, Fishbone and Ribbon) and amorphous carbon has been measured as a function of pressure and temperature. Results have showed as the more graphitic/ordered carbon materials adsorbed less hydrogen than the more amorphous ones. After that and, with the aim of improve the hydrogen adsorption capacity of these carbon materials, they were functionalizated (oxygen surface groups incorporation) and Ni-modificated. Results also showed an important increase of the H 2 adsorption capacity despite the porosity loss that took place after the treatments. Due to the advantages of functionalization and Ni-modification, both treatments were applied at the same time over the most promising carbon materials from the H 2 adsorption point of view, observing again an improvement of the hydrogen adsorption capacity. Finally, the H 2 adsorption capacity of chemically activated carbon materials increased considerably due the pore structure development and even more if activated materials were Ni-modificated.

2009

it is possible to synthesize nanostructured carbon with reproducible properties by controlling the conditions during polymerization, carbonization, and physical activation. Room-temperature adsorption of hydrogen on activated PFA-derived carbon (PFAC) showed that the hydrogen uptake capacity nearly equals that of ACF. The next step is doping this carbon with metals in order to understand and control the mechanisms that influence the hydrogen uptake properties of metalmodified nanostructured carbon materials.