报告内容摘要

Ionic liquids (ILs) are excellent solvents for the dehydrogenation of ammonia borane (AB). The basic properties of AB-ILs are still unclear. In this study, physical and chemical properties such as density, viscosity, melting/freezing/glass transition temperature, and solubility of AB-imidazolium IL solutions were studied as well as their dehydrogenation properties including impurity gas quantification. ILs can solubilize 32~35 wt% of AB and the optimum mixture ratio of AB-ILs was determined as 30 wt% of AB. These liquid solutions have densities of ~0.9 g/cm3, viscosities of 100~250 cP which are similar to motor oil, and glass transition temperatures below –50 °C. AB-ILs desorb <0.09 eq. H2 by several weeks with almost no impurity such as B2H6, NH3, and borazine at room temperature, while water concentration affects dehydrogenation kinetics due to hydrolysis. TG-RGA-IR and DSC results showed that more than 2 mol H2/AB are desorbed from AB-ILs between 80~130 °C with exothermic peaks around 110 °C and limited impurity emissions. Solidification proceeded after desorbed 1.5 eq. H2 and these solid products were harder to soluble in acetonitrile or some other solvents than as mixed AB-ILs. 11B MAS NMR showed that PB forms post-dehydrogenated AB-ILs, and 1H solution and 13C MAS NMR spectra showed that IL peaks slightly shifted due to interaction with PB. This result stands for the final product, PB-IL mixture, appears to be a solid solution, indicating direct regeneration by hydrazine-ammonia method.

报告人简历

Tessui Nakagawa received his Ph.D. in material science in 2009 from the Hiroshima University, Japan. He was a postdoctoral fellow at Los Alamos National Laboratory (LANL), in which his mainly research topic was ammonia borane (NH3BH3) based materials for hydrogen storage. He has published many notable papers about hydrogen storage and regeneration of ammonia borane, one of which was published in Science. He is currently an assistant professor at Faculty of Science (full-time) and Disaster Prevention Research Center for Island Regions (adjunct) in University of the Ryukyus, Japan and his research areas include hydrogen storage, ammonia storage, catalysts, and ionic liquids.

Faculty of Science, University of the Ryukyus

Email: tessui@sci.u-ryukyu.ac.jp

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