Hydrogen Storage in Boron Nitride and Carbon Nanomaterials

Takeo Oku

doi:10.3390/ece-1-d003

Abstract

Thermogravimetry/differential thermogravimetric analysis of boron nitride (BN) nanomaterials showed possibility of hydrogen storage of 1–3 wt%. Possibility of hydrogen gas storage in BN and carbon (C) clusters was investigated by molecular orbital calculations. Chemisorption calculation of hydrogen for BN clusters showed that hydrogen bondings with nitrogenatoms and tetragonal rings were the most stable. Conditions of H2 gas storage in B36N36 cluster, which was considered as a cap structure of B99N99 nanotube, were predicted by first principle single point energy calculations. H2 molecules would beintroduced from hexagonal rings of the cage structure. Stability of H2 molecules inside BN and C clusters was alsoinvestigated by molecular orbital calculations. C and BN clusters showed possibility of hydrogen storage of 6.5 and 4.9wt%, respectively. Chemisorption calculation was also carried out for B24N24 with changing endohedral elements in BNcluster to compare the bonding energy at nitrogen and boron, which showed that Li is a suitable element for hydrogenationto B24N24. BN fullerene materials would store H2 molecule easier than carbon fullerene materials, and its stability for hightemperature would be good.

Highlights

Hydrogen is a carrier with high energy density, and forms only water and heat
After separation of Boron nitride (BN) nanomaterials, hydrogen storage was measured by thermogravimetry/differential thermogravimetric analysis (TG/DTA) at temperatures in the range of 20–300 °C in H2 atmosphere [21]
It means that catalytic elements for synthesis of BN nanotubes should be selected from those with minus formation enthalpy (HforN-HforB)

Summary

Introduction

Hydrogen is a carrier with high energy density, and forms only water and heat. Fossil fuels generate toxic fuels, such as COx, NOx and SOx. clean hydrogen energy is expected as substitute of fossil fuel in the 21st century, and gas storage ability more than 6.5 wt% is needed for car application according to the US Department of Energy. Fullerene-like materials, which consist of light elements, such as boron, Energies 2015, 8 carbon and nitrogen, would store more H2 gas compared to the metal hydrides. Various works have been reported on hydrogen storage ability of carbon nanotubes, fullerenes and nanomaterials [1]. It was reported that multi-walled carbon nanotubes could absorb hydrogen from 1 wt% up to 4.6 wt%

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Conclusion