Abstract
In this study, three types of carbon fibres were used, they were ex-polyacrylonitrile carbon fibres with high bulk modulus, ex-polyacrylonitrile fibres with high strength, and vapour grown carbon fibres. All the samples were subjected to a hydrogen adsorption process at room temperature in an over-pressured atmosphere of 25 bars. The adsorption process was monitored through electrical resistivity measurements. As conditioning of the fibres, a chemical activation by acid etching followed by γ-ray irradiation with 60Co radioisotopes was performed. The surface energy was determined by means of the sessile drop test. Both conditioning treatments are supplementary; the chemical activation works on the outer surface and the γ-irradiation works in the bulk material as well. Apparently, the most significant parameter for hydrogen storage is the crystallite size. From this point of view, the most convenient materials are those with small grain size because hydrogen is accumulated mainly in the grain boundaries.
Highlights
The increase of the pollution level at the atmosphere and the oceans produced by the residues of fossil fuels and atomic residues is disquieting
The choice of the electrical resistivity for tracking the hydrogen adsorption is because the resistivity and the thermoelectric power have been used in the past to study the nature of the adsorption of hydrogen in single-walled carbon nanotubes
If we compare the data of all these pictures, we can see that in pristine state, the high strength fibres are two times more resistive than that of high modulus
Summary
The increase of the pollution level at the atmosphere and the oceans produced by the residues of fossil fuels and atomic residues is disquieting. The progress towards the hydrogen economy [1] is a demand and that must be accepted and implemented. From this perspective, energy alternatives shall partially replace conventional technologies for energy production from fossil fuels that are increasingly scarce. The great handicap of alternative technologies is the storage of hydrogen, especially for hydrogen that will be used in fuel cars. Different possibilities in this field are difficult and expensive, hydrogen as over-pressurized gas, liquid hydrogen, hydrogen stored in compounds is able to be released by chemical reactions, etc. One of the most attractive possibilities is the technique of hydrogen absorbed in porous solids [2]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
