The Seebeck coefficient of vapour grown carbon fibres and carbon fibres made from polyacryolytrile precursor has been studied as a possible parameter to control hydrogen storage inside. The sign of the Seebeck coefficient gives the sign of the dominant charge carriers in the fibres, and when hydrogen is absorbed by the carbonaceous material, mainly as H +, it acts as a positive charge carrier. A simple two-band electronic model has been considered to explain the influence of hydrogenation on the Seebeck's coefficient of these carbon microfibres. The most favourable condition for hydrogen adsorption is a moderately low pressure of hydrogen. Furthermore, it was observed that outgassing is more pronounced than expected in some types of fibres, thereby supporting the proposed presence of hydrogen generated during the manufacturing process. © Springer Science+Business Media, LLC 2012.

The authors would like to thank the Spanish Ministry of Science and Innovation for funding via the Consolider Program (Project NANOTHERM CSD2010-00044).

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