多孔氮化硼三维构造体的可控制备及其储氢性能的研究

Hydrogen can provide highly efficient power without any pollution, however, its storage and delivery is still a big challenge. High-capacity, quick-dynamic, easily-regenerated adsorbent materials are key to realize high-density and safe hydrogen storage in global environmental and energy crises. Porous boron nitride (BN) are envisaged as a new advanced adsorbent for hydrogen storage due to high hydrogen binding energy (compared with carbon) and high stabilities. Currently, the capacity of porous BN is still suffering from low specific surface area and poor pore-engineering limited by its synthetic complexity. The specific surface area of porous BN is less than 1000 m2/g by templating methods, and is still less than 2000 m2/g by non-templating methods including chemical-blowing and melamine-boric acid route developed by us in 2011-2015. This project proposes to explore porous BN 3D architecture, via developing a route coupling Cx-BN phase-separation pore-engineering and 3D design. Owing to the high surface area, high hydrogen binding energy, and 3D connected pores, the porous BN 3D architecture will enable the quick and large-capacity hydrogen storage under moderate conditions: small temperature variation, and low applied pressure.

氢是一种高效的清洁能源，温和条件下储氢密度低是氢能发展的瓶颈之一，高容量、快速吸附、稳定易再生是吸附储氢材料的发展目标。多孔氮化硼的氢气结合能高，有望成为高性能储氢材料。模板法制备的多孔氮化硼的比表面积均低于1000 m2/g；申请人在2011-2015年发展了发泡法、氰胺类-硼酸法2种非模板法，分别实现了大孔性发泡体、富含微孔的多孔微米带，后者比表面积首次突破了1000 m2/g。但所有这些多孔氮化硼尚未达到2000 m2/g，远滞后于多孔碳。针对这一难题，依靠在氮化硼纳米片、多孔氮化硼、石墨烯领域的多年基础，申请人设计一种基于碳-硼氮相分离的微孔制造工程、基于三维设计的介孔工程，以构建一种新型多孔氮化硼——高比表面积的多孔氮化硼三维构造体，并研究其孔隙调控、吸附物理化学。利用其高比表面积、高氢气结合能、三维贯穿的孔结构等优势，可以在较低的循环温度压力下，实现快速吸附、高容量的氢气储存。

氢能是一种清洁能源，但氢气储存容量较低是氢能发展的瓶颈之一。本课题致力于设计合成高比表面积多孔网络结构的氮化硼材料，并将多孔氮化硼用于吸附储氢，以实现高容量的氢气储存。本项目首先发展了三种制备方法，合成了三种多孔氮化硼材料。提出了基于“硼酸/硼砂—氰胺”体系的热裂解制备工艺，包括硼砂氰胺法、氰胺醛缩聚法、硼酸氰胺法。基于这些方法，探索并优化了若干制备工艺参数，包括投料比例和反应温度等，调控了多孔氮化硼的孔结构和形貌，最终获得了具有高比表面积和发达孔结构的多孔氮化硼材料，其比表面积高达1410 m2/g。本项目进一步研究了三种多孔氮化硼材料的气体吸附和染料吸附特性，指出了其吸附相关应用，例如储氢和吸附净水。本项目最后将多孔氮化硼材料用于储氢，分析了比表面积对储氢性能的影响。其中，利用氰胺醛缩聚法制备的多孔氮化硼，在77 K、9 MPa的条件下，储氢容量达到5.3 wt%，这处于氮化硼储氢领域的先进水平。