The storage of hydrogen in carbon nanotubes requires appropriate chemical activators in suitable geometry. In this study, the role of boron substitution in carbon nanotubes is demonstrated for activation and storage of hydrogen. © 2007 International Association for Hydrogen Energy.

M. Sankaran

Balasubramanian Viswanathan

boron

Density functional theory

Hydrogen storage

Substitution reactions

CHEMICAL ACTIVATORS

Heteroatoms

HYDROGEN ACTIVATION

VOLUMETRIC METHODS

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

International Journal of Hydrogen Energy

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.

Hydrogen storage on boron substituted carbon materials

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.

Carbon

Hydrogen storage in boron substituted carbon nanotubes

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.

The role of heteroatoms in carbon nanotubes for hydrogen storage

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.

Fullerenes Nanotubes and Carbon Nanostructures

Boron-substituted fullerenes - Can they be one of the options for hydrogen storage?

The template carbonization of polyphenyl acetylene yielded well aligned, cylindrical, mono disperse carbon nanotubes (CNT), which are effectively utilized to load Pt, Pt-Ru, and Pt-WO3 nano particles. The nanoparticles are effectively dispersed inside the tube with the particle sizes of around 1.2, 1.6, and 10 nm for Pt, Pt-Ru, and Pt-WO3, respectively. The electrochemical surface area of the CNT-based electrode was higher compared to the Vulcun XC 72R carbon, graphite, and glassy carbon (GC) electrodes. The X-ray photoelectron spectroscopic measurements revealed that the Pt and Ru are in metallic state and W is in +VI oxidation state. The higher activity of GC/CNT-Pt-WO3-Nafion for methanol oxidation compared to GC/CNT/Pt-Ru-Nafion and GC/CNT/Pt-Nafion suggests the better utilization of the catalytic particles. The stability of the electrode for methanol oxidation polarized at +0.6 V follows the order of GC/CNT/Pt-Ru-Nafion &gt; GC/CNT/Pt-WO3 &gt; GC/CNT/Pt-Nafion, and for the electrodes polarized at +0.4 V, the order is GC/CNT/Pt-WO3-Nafion &gt; GC/CNT/Pt-Ru-Nafion &gt; GC/CNT/Pt-Nafion. The differences in the stability possibly suggest the better tolerance of the adsorbed species of methanol oxidation for the GC/CNT/Pt-WO3-Nafion electrode (when it is polarized at +0.4 V).

Journal	International Journal of Hydrogen Energy
ISSN	03603199
Open Access	No