过渡金属硼化物非晶超细颗粒的可控制备及其对轻金属硼氢化物可逆储氢的催化改性机理

Mg(BH4)2 is a new high capacity hydrogen storage system with suitable hydrogen absorption/desorption thermodynamics properties. The key scientific issue is how to over come the high dynamic barrier during hydrogenation/dehydrogenation reaction in this system, and then realize the reversible hydrogen storage process under mild conditions. According to the early research results that amorphous TiB2 and NbB2 exhibited excellent catalysis reversible hydrogen storage property of Li-Mg-B-H system, it is proposed to investigate the controllable preparation of series amorphous transition metal borides ultrafine particles of TM-B (M=Sc, Ti, Nb, Fe, Co, Ni), which can act as the high efficiency catalysts to improve hydrogen absorption/desorption kinetics property. Moreover, the effects of different species, particle sizes, dopant amounts of TM-B amorphous catalysts and loading catalysts on the graphene surface on hydrogen absorption/desorption kinetics properties of Mg(BH4)2 will be investigated systematically. The clarification will be conducted on the evolution relationship between microstructure transformation and hydrogen absorption/desorption properties of catalytic modification system during hydrogenation/dehydrogenation reaction. The essential characteristics of TM-B based catalytic components and its catalytic mechanism will be revealed accurately. On the basis, the effective approaches to improve the reversible hydrogen storage properties of metal borohydride will be also researched, in order to lay the foundation for further application research for these high efficiency catalysts and high capacity light metal borohydride.

Mg(BH4)2是一种吸放氢热力学性能理想的高容量新型储氢体系，其存在的核心科学问题是如何克服体系在吸放氢反应中过高的动力学势垒，以实现温和条件下的可逆储氢过程。本项目根据前期发现非晶TiB2和NbB2对Li-Mg-B-H体系可逆储氢具有优异催化作用的研究结果，拟开展系列过渡金属硼化物TM-B (M=Sc，Ti，Nb，Fe，Co，Ni)非晶超细颗粒的可控制备研究，并将其作为高效催化剂以改善Mg(BH4)2体系的吸放氢动力学性能，系统考察TM-B非晶催化剂的不同种类、粒径、掺杂量以及将其负载于石墨烯表面对Mg(BH4)2吸放氢动力学的影响规律，查明催化改性体系在储氢过程中的微观结构演变及其与吸放氢性能的内在联系，准确揭示TM-B基催化组元的本质特征以及催化作用机理。在此基础上，进一步探究改善金属硼氢化物可逆储氢性能的有效途径，为此类高效催化剂和高容量轻金属硼氢化物的后续应用研究奠定基础。

为有效改善金属基硼氢化物储氢材料的吸放氢性能，本项目制备了系列过渡金属硼化物非晶超细颗粒，系统研究掌握了非晶过渡金属硼化物TM-B（TM=Ti，Nb，Fe，Co和Ni）的种类、粒径和掺杂量对Mg(BH4)2基储氢体系体系可逆吸放氢动力学性能的影响规律，同步辐射分析、固体核磁共振等先进表征技术精确研究TM-B非晶催化剂与Mg(BH4)2体系的相互作用关系，查明了TM-B非晶催化剂掺杂Mg(BH4)2体系等硼氢化物在吸放氢过程中物相结构演变规律及其与吸放氢动力学性能之间的相互作用关系，从原子微观结构层次上阐明Mg(BH4)2储氢体系的催化活性组元，从电子价键结构层次上阐明Mg(BH4)2储氢体系的催化作用机理。通过石墨烯/碳纳米管负载过渡金属超细颗粒提高催化剂的催化活性和热稳定性，并实现其对Mg基复合储氢体系的催化增强效果，阐明此类过渡金属催化剂对Li2B12H12和MgB12H12等中间产物吸放氢动力学性能的改善规律，从而研究开发出吸放氢动力学性能优异的金属配位硼氢化物体系，并进一步发展新型Mg(BH4)2基复合储氢体系，为此类高效催化剂以及高容量储氢材料的后续应用研究奠定基础。结合本项目研究任务，发表了SCI收录论文32篇，申请国家发明专利10项，其中3项已授权。