Hydrogen adsorption in transition metal carbon nano-structures
- PDF / 1,061,262 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 31 Downloads / 194 Views
Hydrogen adsorption in transition metal carbon nano-structures Yun Xia Yang · Ranjeet K. Singh · Paul A. Webley
Received: 30 April 2007 / Revised: 28 October 2007 / Accepted: 18 December 2007 / Published online: 23 January 2008 © Springer Science+Business Media, LLC 2008
Abstract Templated microporous carbons were synthesized from metal impregnated zeolite Y templates. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were employed to characterize morphology and structure of the generated carbon materials. The surface area, micro- and meso-pore volumes, as well as the pore size distribution of all the carbon materials were determined by N2 adsorption at 77 K and correlated to their hydrogen storage capacity. All the hydrogen adsorption isotherms were Type 1 and reversible, indicating physisorption at 77 K. Most templated carbons show good hydrogen storage with the best sample Rh-C having surface area 1817 m2 /g and micropore volume 1.04 cm3 /g, achieving the highest as 8.8 mmol/g hydrogen storage capacity at 77 K, 1 bar. Comparison between activated carbons and synthesized templated carbons revealed that the hydrogen adsorption in the latter carbon samples occurs mainly by pore filling and smaller pores of sizes around 6 Å to 8 Å are filled initially, followed by larger micropores. Overall, hydrogen adsorption was found to be dependent on the micropore volume as well as the pore-size, larger micropore volumes showing higher hydrogen adsorption capacity.
Keywords Carbon nanostructures · Hydrogen storage · Adsorption
Y.X. Yang · R.K. Singh · P.A. Webley () Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia e-mail: [email protected]
1 Introduction Hydrogen is considered to be an ideal fuel for solving the energy crisis as well as minimizing environmental impact. Four different methods to store hydrogen are currently available: liquid hydrogen (Aceves et al. 2006), compressed gas, metal hydrides (Cooper et al. 2003; Schlapbach and Zuttel 2001; Zuttel 2004) and sorption on different porous materials such as carbon materials (de la Casa-Lillo et al. 2002; Hirscher et al. 2002; Lueking and Yang 2003), zeolites (Yoon 1993), metal organic frameworks (Rosi et al. 2003; Fichtner et al. 2005; Li et al. 2006), and nano-structured metal particle or films. (Hou et al. 2005a; Hou et al. 2005b; Bobet et al. 2004) Cryogenic liquid hydrogen systems experience potential hydrogen losses due to evaporation; compressed hydrogen system exhibit safety problems and are still too large for automotive applications; metal hydrides systems have high weight and cost concerns, and moreover high temperatures are often required to release hydrogen. Chemical hydrogen storage from ammonia-borane (Keaton et al. 2007) shows promising results on dehydrogenation at relatively low temperatures, however, precursor synthesis is yet to be mastered. Carbon materials have received attention in this area, because of their low density, high surface area, good chemical stability, and ame
Data Loading...
