TITLE:
Effects of Gamma Irradiation on the Kinetics of the Adsorption and Desorption of Hydrogen in Carbon Microfibres
AUTHORS:
Cesar Mota, Mario Culebras, Andrés Cantarero, Antonio Madroñero, Clara Maria Gómez, Jose María Amo, Jose Ignacio Robla
KEYWORDS:
Carbon Fiber; Gamma Irradiation; Hydrogen Adsorption; Electrical Resistivity; Raman Spectroscopy
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.3 No.2,
June
5,
2013
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.