Carbon materials should have specific centers for hydrogen adsorption/absorption. The Universal Force Field and Density Functional Theory have been used to find the role of heteroatom substitution in carbon nanotubes as an activator. The effect of various heteroatoms like nitrogen, phosphorus, sulphur and boron for hydrogen activation and their geometrical positions has been identified for easy hydrogenation. This will be one of the possible centers where hydrogen adsorption/absorption is initiated. © 2006 Elsevier Ltd. All rights reserved.

M. Sankaran

Balasubramanian Viswanathan

Absorption

Adsorption

Hydrogenation

nitrogen

Probability density function

Storage (materials)

Surface Properties

Carbon materials

HYDROGEN ACTIVATION

Hydrogen adsorption

Carbon nanotubes

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Carbon

The need for efficient and renewable energy fuels is growing stronger with environmental consciousness, stringent emission norms, rising fossil fuel prices and their depleting stocks. Hydrogen could be a significant replacement for fossil fuels if targets of volumetric and gravimetric densities required for the automobile industry can be met. In this regard, hydrogen economy and hydrogen storage have become thrust areas of research in the past few decades. It is possible to store hydrogen in the solid state as chemically bound hydrogen using metal/alloy nanostructures with favorable adsorption sites. These nanoparticles when dispersed over suitable carbon nanomaterials exhibit better storage capabilities and improved adsorption-desorption kinetics. High surface area carbon supports such as graphene favor good dispersion of catalyst nanoparticles alleviating their agglomeration and modulating the interaction strength between hydrogen atoms and metal nanoparticles by providing pathways for chemi-physisorption of hydrogen in these nanocomposites. In this review, the contribution of chemically modified graphene-based materials and their composites with metal/alloy catalyst nanostructures in the field of hydrogen storage is reviewed and its future outlook discussed. © The Royal Society of Chemistry 2017.

Fulltext

Journal of Materials Chemistry A

Recent advances in hydrogen storage using catalytically and chemically modified graphene nanocomposites

Hydrogen storage capacity of boron substituted carbon materials synthesized by the carbonization of resorcinol and triethylborate as carbon and boron sources respectively is reported. The effects of the boron-doping and carbonization temperature and the role of functional groups have been investigated. The hydrogen adsorption capacity has been studied with a high pressure volumetric analyzer (HPVA) and a maximum of 5.9 wt% hydrogen storage capacity was observed at 298 K and 100 bar pressure. At 77 K in both carbon samples (namely BC-600 or BC-800) show only fractional weight percent of hydrogen sorption (1.1 and 0.5 wt%). The nearly 5 weight % hydrogen storage was obtained by loading heteroatom (B) to carbon sample at 298 K and 100 bar. © 2016 Hydrogen Energy Publications, LLC.

International Journal of Hydrogen Energy

Hydrogen storage on boron substituted carbon materials

Recent research developments reveal that nanomaterials, especially carbon nanomaterials, can play a significant role in the performance enhancement of energy conversion and storage devices. The synthesis procedure of nanomaterials, however, remains one of the governing factors for their wide scale implementation. In this paper, an in situ synthesis method to prepare palladium nanoparticle decorated nitrogen doped graphene sheets (Pd/N-SG) using focused solar radiation is developed. The present synthesis technique combines three processes simultaneously, namely (a) graphene sheet formation, (b) nitrogen doping of graphene sheets and (c) metal precursor reduction to metal nanoparticles, in one step through a green approach. The hydrogen storage properties of the Pd/N-SG sample are investigated using high pressure Sievert's apparatus and the sample exhibits an excellent hydrogen storage capacity of 4.3 wt% at room temperature (25 °C and 4 MPa hydrogen pressure). The method developed for the synthesis is environmentally benign, easy to adopt and economical. Also, the proposed one-step synthesis method can be easily scaled up to large quantities and this opens a new pathway for the synthesis of nanomaterials for use in the renewable energy field. © 2013 The Royal Society of Chemistry.

Solar light assisted green synthesis of palladium nanoparticle decorated nitrogen doped graphene for hydrogen storage application

A high hydrogen storage capacity for palladium decorated nitrogen-doped hydrogen exfoliated graphene nanocomposite is demonstrated under moderate temperature and pressure conditions. The nitrogen doping of hydrogen exfoliated graphene is done by nitrogen plasma treatment, and palladium nanoparticles are decorated over nitrogen-doped graphene by a modified polyol reduction technique. An increase of 66% is achieved by nitrogen doping in the hydrogen uptake capacity of hydrogen exfoliated graphene at room temperature and 2 MPa pressure. A further enhancement by 124% is attained in the hydrogen uptake capacity by palladium nanoparticle (Pd NP) decoration over nitrogen-doped graphene. The high dispersion of Pd NP over nitrogen-doped graphene sheets and strengthened interaction between the nitrogen-doped graphene sheets and Pd NP catalyze the dissociation of hydrogen molecules and subsequent migration of hydrogen atoms on the doped graphene sheets. The results of a systematic study on graphene, nitrogen-doped graphene, and palladium decorated nitrogen-doped graphene nanocomposites are discussed. A nexus between the catalyst support and catalyst particles is believed to yield the high hydrogen uptake capacities obtained. © 2012 American Chemical Society.

Langmuir

Effect of nitrogen doping on hydrogen storage capacity of palladium decorated graphene

Carbon materials should have specific centers for hydrogen adsorption/absorption. The role of heteroatom substitution in carbon nanotubes as an activator has been identified by Density Functional Theory. The effect of various hetero-atoms like nitrogen, phosphorus, sulphur and boron for hydrogen activation and their geometrical positions has been recognized as the one of the possible reasons for easy hydrogenation. Experimentally, nitrogen and boron containing carbon nanotubes have been synthesized by using template method. The hydrogen absorption capacity of these materials has been evaluated. It is shown that, there is a need to stabilize nitrogen in the carbon nanotube framework for reproducible hydrogen uptake. In the case of boron containing carbon nanotubes, two different chemical environment of boron facilitates hydrogen interaction. They exhibit a maximum of 2 wt.% of hydrogen storage capacity at 80 bar and 300 K. This configuration has a bearing in hydrogen sorption characteristics. © 2008 Elsevier B.V. All rights reserved.

Diamond and Related Materials

Hetero-atoms as activation centers for hydrogen absorption in carbon nanotubes

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 13C &amp; 11B MAS NMR techniques. The presence of boron in different chemical environment has been visualized by XPS and 11B MAS NMR. The hydrogen absorption activity has been studied and a maximum of 2 wt% hydrogen storage capacity was observed. © 2007 Elsevier Ltd. All rights reserved.

Hydrogen storage in boron substituted carbon nanotubes

The need for an activator for hydrogenation of carbon nanomaterials is outlined. The positions at which boron atoms are substituted in the fullerene network have been identified for easy hydrogenation.

Journal	Carbon
ISSN	00086223
Open Access	No