MATERIAIS 2007 Porto, 1-4 April 2007
SINGLE WALLED CARBON NANOTUBE/ZEOLITE COMPOSITES: NOVEL MEDIA FOR HYDROGEN ADSORPTION Margarida C. Coelho 1, *, Elby Titus 1, Gil Cabral 1, Joana C. Madaleno 1, Tolou Shokuhfar 1, José Grácio 1 1 Department of Mechanical Engineering, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal * corresponding author:
[email protected] Keywords: Hydrogen storage, Zeolites, Carbon nanotubes.
Abstract Today, many scientists, engineers, companies, governamental and non-governamental agencies agree that hydrogen will be an important fuel in the future. A relevant application of hydrogen energy is related to the problem of air pollution caused by road traffic emissions in urban areas, namely to reduce CO2 emissions. A low-cost, high-capacity, safe and compact hydrogen storage medium is a major challenge for hydrogen use in transportation. Hence the focus of the modern research is to obtain a media that absorbs and releases a large quantity of hydrogen easily and reliably. Carbon nanotubes (CNTs) can store hydrogen and this material has been considered as a candidate for hydrogen storage media. However, there has been a wide range in the hydrogen storage capacity published in the literature [1, 2, 3] and the difficulty in reproducibility is attributed to the impurities and defects present in CNTs. In this paper, we have examined the hydrogen storage property of single walled carbon nanotubes (SWCNT)/Zeolite composite and the results were compared with as-grown SWCNT. We have used pure SWCNT for the reproducibility of the results. We have tested the hydrogen absorption and desorption properties of the SWCNT/Zeolite composite and SWCNT under pure hydrogen at 150° C for up to 300 cycles. Further, we have treated SWCNTs and SWCNT/Zeolite composite with atomic hydrogen generated in a glow discharge hydrogen plasma in order to study the actual mechanism of hydrogen adsorption onto SWCNT/Zeolite composite. Simulations were also performed on the basis of experimental values.
References [1] G. Turnes Palomino, M.R. Llop Carayol, C. Otero Areán. Hydrogen adsorption on magnesium-exchanged zeolites. Journal of Materials Chemistry, 16, 2884-2885, 2006. [2] Guay, P., Modélisation Monte-Carlo de l’adsorption de l’hydrogène dans les nanostructures de carbone. Mémoire présenté pour l’obtention du grade de Maître ès sciences, INRS Énergie, Matériaux et Télécommunications, 2003. [3] IEA, Hydrogen Production and Storage – R&D Priorities and Gaps. International Energy Agency – Hydrogen Co-ordination Group, Hydrogen Implementing Agreement, 2006.
Acknowledgements The research work of M.C. Coelho, E. Titus, J.C. Madaleno and T. Shokuhfar are supported by Scholarships of the Portuguese Science and Technology Foundation (SFRH/BPD/21317/2005, SFRH/BPD/14434/2003, SFRH/BPD/24615/2005 and SFRH/BD/29123/2006 respectively).
