轻金属硼基氢化物复合材料的制备及储氢性能研究

High volumetric and gravimetric density hydrogen storage is the key technique for the unique demands of a low temperature automotive fuel cell. The light metal boron-based hydride nanocomposite materials become a research highlight due to its high capacity hydrogen storage. However, their application has been impractical as a result of the great difficulties due to the following limitations: a) unfavorable thermodynamics (they require high temperatures to release hydrogen), b) poor kinetics (low rates of hydrogen release and uptake), c) decomposition pathways involving the release of undesirable by-products. The goal of this project is to explore the preparation and hydrogen storage properties of the light metal boron-based hydride nanocomposite materials with hierarchical porous structure. The correlation between microstructure and the hydrogenation properties will be analyzed via DSC, TG, XRD, Raman spectroscopy, SEM, TEM/HRTEM, etc. The thermodynamic and kinetic parameters such as ΔH, ΔS, and Ea have also evaluated according to the Van't Hoff and Arrhenius equation. The density functional theory (DFT) calculations will be applied to clarify the catalytic reaction mechanism. The objectives of the proposed research is to improve the hydrogenation/dehydrogenation performance of the light metal boron-based hydride nanocomposite materials.

高体积和质量密度储氢材料是低温燃料电池等氢能应用的关键，轻金属硼基氢化物因具有高的储氢量而成为研究热点，但差的热力学性能（需较高温度放氢）、缓慢的动力学性能（吸放氢速度缓慢）和分解过程中释放副产物影响其应用。本项目将探索具有分级多孔结构的轻金属硼基氢化物纳米复合材料的制备及储氢性能。通过差热（DSC）、热重（TG）、X射线衍射（XRD）、拉曼光谱（Raman）、扫描电镜（SEM）和透射电镜（TEM/HRTEM）等手段分析微观结构与储氢性能之间的内在联系，根据Van't Hoff及Arrhenius方程计算吸/放氢反应的焓变（ΔH）、熵变（ΔS）和反应活化能（Ea）等热力学和动力学参数，结合密度泛函等理论计算，阐明催化及反应机理，提高轻金属硼基氢化物材料的储/放氢性能。

氢能因其高能量密度和环境友好成为众多清洁能源的候选者之一，可是，储氢材料仍面临高容量、低的热稳定性、快的动力学和高安全等诸多挑战。在众多储氢材料中，轻金属硼基氢化物具有高的理论质量和体积储氢容量而备受关注，但高脱氢温度和差的动力学性能严重影响实际应用。.项目以NH3BH3、Mg(BH4)2等储氢材料为研究对象，采用多孔碳、碳纳米管、基于Ni和Co的纳米多孔材料作为载体/催化剂，改善了氨硼烷及Mg(BH4)2等硼基氢化物的放氢性能，以及催化剂的循环使用效率，研究了其可能的吸放氢机理。