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Study on hydrogen storage properties of Mg nanoparticles confined in carbon aerogels 总被引:1,自引:0,他引:1
Yana Liu Jianxin Zou Xiaoqin Zeng Xiaomei Wu Huyong Tian Wenjiang Ding Jun Wang Anastasia Walter 《International Journal of Hydrogen Energy》2013
Magnesium nanoparticles confined in carbon aerogels were successfully synthesized through hydrogenation of infiltrated dibutyl-magnesium followed by hydrogen desorption at 623 K. The average crystallite size of Mg nanoparticle is calculated to be 19.3 nm based on X-ray diffraction analyses. TEM observations showed that the size of MgH2 particle is mainly distributed in the range from 5.0 to 20.0 nm, with a majority portion smaller than 10.0 nm. The hydrogenation and dehydrogenation enthalpies of the confined Mg are determined to be −65.1 ± 1.56 kJ/mol H2 and 68.8 ± 1.03 kJ/mol H2 by Pressure–composition–temperature tests, respectively, slightly lower than the corresponding enthalpies for pure Mg. In addition, the apparent activation energy for hydrogen absorption is determined to be 29.4 kJ/mol H2, much lower than that of the micro-size Mg particles. These results indicate that the thermodynamic and absorption kinetic properties of confined Mg nanoparticles can be significantly improved due to the ‘nanosize effect’. 相似文献