Wu Xuanjun, Li Lei, Fang Tiange, Wang YeTong, Cai Weiquan, Xiang Zhonghua
School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, P. R. China.
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Phys Chem Chem Phys. 2017 Mar 29;19(13):9261-9269. doi: 10.1039/c7cp01230f.
By inserting an acetylene bond into the organic linkers of porous materials, hydrogen storage can be significantly enhanced; however, the mechanism of this enhancement remains elusive. Herein, we developed a new diamond-like carbon allotrope (referred as diamond-like diacetylene a.k.a. DDA) with medium pores constructed by inserting -C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C- ligands into the -C-C- bonds of diamond. The structural, mechanical, and electrical properties, as well as hydrogen storage capacities were investigated for this novel material using density functional theory and Monte Carlo simulations. The optimized geometry of DDA shows a high surface area and free pore volume of ca. 5498.76 m g and 2.0486 m g, respectively. DDA also exhibits structural stability and special electronic properties. Interestingly, DDA exhibits exceptional gravimetric hydrogen storage capacity as well as volumetric one. The excess gravimetric and volumetric H uptakes at 77 K and 2.0 MPa hit a maximum of 14.12 wt% and 603.35 cm (STP) cm, respectively, which substantially exceeds those previously reported for MOF or PAF materials. Even at 243 K and 12 MPa, the total gravimetric H uptake of DDA reaches 5.38 wt%. To the best of our knowledge, DDA is one of porous materials with the maximum physical hydrogen uptake. It is also one of the few materials that can be close to meeting hydrogen storage target of the US department of energy at room temperature. Significantly, DDA shows the deliverable hydrogen storage capacity up to 5.28 wt% at room temperature. Through analyzing the effect of the acetylene position in the DLCAs on their hydrogen storage capacities, we found that the high hydrogen adsorption performance of DDA is mainly attributed to its high surface area, large number of adsorption sites, and appropriate binding energy. In summary, the newly developed DDA is a promising candidate for hydrogen storage and provides a new possibility for synthesizing high-performance adsorbents.
通过在多孔材料的有机连接体中插入乙炔键，储氢能力可得到显著提高；然而，这种增强的机制仍然难以捉摸。在此，我们开发了一种新型类金刚石碳同素异形体（称为类金刚石二乙炔，即DDA），它具有中孔结构，是通过将-C≡C-C≡C-配体插入金刚石的-C-C-键中构建而成。使用密度泛函理论和蒙特卡罗模拟对这种新型材料的结构、力学和电学性质以及储氢能力进行了研究。DDA的优化几何结构显示出高表面积和自由孔体积，分别约为5498.76 m²/g和2.0486 m³/g。DDA还表现出结构稳定性和特殊的电子性质。有趣的是，DDA表现出优异的重量储氢能力和体积储氢能力。在77 K和2.0 MPa下，过量的重量和体积氢吸收量分别达到最大值14.12 wt%和603.35 cm³(STP)/cm³，这大大超过了先前报道的MOF或PAF材料。即使在243 K和12 MPa下，DDA的总重量氢吸收量也达到5.38 wt%。据我们所知，DDA是具有最大物理氢吸收量的多孔材料之一。它也是少数几种在室温下可接近满足美国能源部储氢目标的材料之一。值得注意的是，DDA在室温下的可交付储氢能力高达5.28 wt%。通过分析类金刚石碳同素异形体中乙炔位置对其储氢能力的影响，我们发现DDA的高氢吸附性能主要归因于其高表面积、大量的吸附位点和合适的结合能。总之，新开发的DDA是一种有前途的储氢候选材料，并为合成高性能吸附剂提供了新的可能性。
