纳米多孔金属氧化物限域的硼氢化物储氢性能研究

Borohydrides are considered to be one of the most promising hydrogen storage materials because of their high gravimetric and volumetric hydrogen storage capacities. However, High desorption temperature，slow thermodynamic and poisonous by-products make these materials unfavorable. To solve these problems, this proposal will enlist nanoporous metal oxide （such as TiO2, ZnO nanotube） to confine borohydrides. In this system, the dispersion of the hydrides will be improved, the size of the particles will be reduced and the surface area of the complex hydrides will be increased. Theoretically, the de-/rehydrogenation temperature will be decreased dramatically. The hydrogen storage performance of these materials will be improved and the poisonous species will be inhibited. This study aims to investigate the interaction of the borohydrides (such as NH3BH3,LiBH4) and nanoporous metal oxide, explore the mechanism of the hydrogen desorption, examine the effects of the electronic surface states, nanopore size and defects on the hydrogen storage performance of the borohydrides by density functional theory simulation combined with experimental tests such as spectroscopy and XRD, et al. Additionally, through this study, we expect to understand the structure and the relevancy between nanoconfinement of the particles and hydrogen storage performance clearly. This proposal will has great impact and provide wide instruction for nanoconfined hydrogen storage materials.

由于具有较高的质量和体积储氢容量，硼氢化物被认为是最具潜力的储氢材料之一。然而，硼氢化物储氢材料仍然存在吸放氢温度高、动力学性能差、易生成有害物种等尚未解决的问题。本研究拟采用纳米多孔金属氧化物（如TiO2，ZnO 纳米管等）对硼氢化物进行尺寸约束，提高硼氢化物的分散性，以期得到纳米颗粒分布窄、比表面积大、尺寸可控的纳米硼氢化物，降低吸放氢反应温度，改善吸放氢动力学性能,抑制有害物种的生成。采用密度泛函理论计算模拟并结合光谱、XRD等实验检测手段，深入研究纳米多孔金属氧化物限域的NH3BH3和LiBH4等硼氢化物的放氢反应机理，阐明多孔金属氧化物电子结构、孔道尺寸、缺陷与硼氢化物吸放氢性能间的关联性，清楚认识硼氢化物在吸、放氢过程中结构变化规律, 从而为探索设计新型高容量储氢材料提供指导。

由于具有较高的质量和体积储氢容量，硼氢化物储氢材料被认为是最具潜力的储氢材料之一。然而，硼氢化物储氢材料仍然存在吸放氢温度高、动力学性能差、易生成有害物种等尚未解决的问题。本项目采用多种方法等对硼氢化物进行尺寸约束，提高了硼氢化物的分散性，得到纳米颗粒分布窄、比表面积大、尺寸可控的纳米硼氢化物，降低了吸放氢反应温度，改善了吸放氢动力学性能,抑制了有害物种的生成。深入研究了纳米多孔金属氧化物限域硼氢化物的放氢反应机理，阐明了多孔材料电子结构、孔道尺寸、缺陷与硼氢化物吸放氢性能间的关联性。制备了Co-B-TiO2纳米多孔复合材料，用于硼氢化物储氢材料催化剂，表现出良好的性能。采用球磨法制备了尿素复合的Ca(BH4)2•4CO(NH2)2复合氢化物，该氢化物具有良好的储氢性能，在250 °C以下，放氢5.2wt%。采用过渡金属卤化物对硼氢化物进行催化，其中CoCl2可以有效降低硼氢化物的放氢温度。清楚认识硼氢化物在吸、放氢过程中结构变化规律, 从而为探索设计新型高容量储氢材料提供指导。在项目的资助下，发表论文14篇，其中被SCI收录14篇，申请专利2项，取得了圆满成功。