功能化石墨烯负载2LiBH4/MgH2-TM纳米复合体系的三维自组装及其可逆储氢机制

LiBH4 metal complex hydride is one of the research hotspots for hydrogen storage materials due to its extremely high capacity. However, the stable thermodynamics, sluggish kinetics and poor reversibility for hydrogenation/dehydrogenation hindered its practical applications. According to our previous investigations on the nano-confinement, catalysis and composite modification for LiBH4, we propose to design and fabricate a novel hierarchical structure with the composition of 2LiBH4/MgH2-TM@Graphene nano-composite, in which the LiBH4 and MgH2 nanoparticles are uniformly embedded in the functionalized graphene matrix, ensuring the intimate contact between the active species, and minimizing the species diffuse distances during the reaction, while the transition metal nanoparticles anchored on the graphene serve as the ideal catalysts for the dehydrogenation/hydrogenation. This specially designed composite with unique sandwich-structures can be formed by self-assembly mechanism, and will combine the effects of reactive hydride composite, nano-confinement, induction of doped elements (B/N/F) on graphene, and catalysis of transition metal nanoparticles, which would significantly advance the hydrogen storage properties of LiBH4-based composites, and provide important insights into metal complex hydrides with high storage capacity for the next generation hydrogen storage materials. Furthermore, the present promising approaches, associated with the theoretical calculations would provide the foundations for further intensive research for these light metal complex hydrides as hydrogen storage materials, and may even revive other hydrogen storage systems.

金属配位氢化物LiBH4是目前高容量储氢材料的研究热点之一，目前尚存在吸放氢热力学性质过于稳定、动力学缓慢和可逆储氢性能较差等关键科学问题。本项目依据前期对LiBH4分别进行催化掺杂、纳米限域和复合改性等的研究基础，拟通过B、N、F等元素修饰对石墨烯基体进行功能化改性，并利用分步自组装技术将过渡金属(TM)纳米催化剂和MgH2、LiBH4均匀负载于功能化石墨烯(GR)表面，以获得三维自组装结构与储氢性能均可调控的2LiBH4/MgH2-TM@GR纳米复合储氢体系。通过实验与理论研究相关联，揭示功能化石墨烯负载、纳米过渡金属催化以及与MgH2复合改性对LiBH4体系可逆储氢性能的协同改性作用机理，探索进一步改善金属配位氢化物可逆储氢性能的有效途径。获取必要的基础数据及信息，为此类金属氢化物复合储氢材料的后续应用研究提供理论指导和实验依据。

金属配位氢化物LiBH4是高容量储氢材料的研究热点之一，目前尚存在吸放氢热力学性质过于稳定、动力学缓慢和可逆储氢性能较差等关键科学问题。本项目按计划开展了LiBH4、MgH2的纳米催化改性以及功能化石墨烯（GR）负载2LiBH4/MgH2-TM@GR纳米复合储氢体系的三维自组装可控制备及其可逆储氢机制研究。通过B、N、F等元素修饰对石墨烯等低维碳材料进行了功能化改性，并利用自组装技术将过渡金属（TM：Ti、Ni、Co、Nb等）纳米催化剂、MgH2、LiBH4成功负载于功能化石墨烯等低维碳材料表面，掌握了其自组装行为影响机制以及三维可控构筑过程。比较研究了低维碳材料的B、N、F功能化修饰改性以及过渡金属纳米催化剂对MgH2、LiBH4和2LiBH4/MgH2-TM@GR 纳米复合体系吸放氢热/动力学和可逆储氢性能的影响规律，阐明了功能化石墨烯负载空间约束、纳米过渡金属催化、与MgH2复合改性对LiBH4及其它配位氢化物储氢体系的协同作用机理。本项目已完成了预定的研究任务，并获取了大量相关基础数据及信息，为此类高容量储氢材料体系的后续应用研究提供了理论指导和实验依据。结合本项目研究任务，共培养博士毕业生1名、硕士毕业生1名，目前在读博士生2名、硕士生2名；研究成果申请国家发明专利5项，其中3项已授权；发表SCI收录论文30篇，全部标注了本项目资助号。