Abstract

The aim of this work is to study the behaviour of Vapour Growth Carbon Fibres (VGCF) with different treatments after the intake and outgassing of hydrogen takes place.

The VGCFs are prepared via catalyzed decomposition of a mixture of hydrogen and methane. The catalyst was minute particles of iron. The fibre thickness was about 10 to 20 microns and they have a trunk-tree inner structure.

Two different treatments are tested to improve the properties of the as grown samples: a heat treatment under vacuum conditions and an acid etching with nitric acid. The desorption kinetics of the three type of samples is studied measuring the electrical resistivity during the hydrogen outgassing. As a result, the surface treatment with acid etching seems to be an efficient method to improve the kinetics of the hydrogen sorption in the first hydrogenation cycle.

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