标题： 热传输以及氢吸附对Linde类型A沸石咪唑酯框架的影响 显示英文标题

标题： Thermal transport and the impact of hydrogen adsorption in Linde Type A zeolitic imidazolate frameworks

摘要： 热传导在金属有机框架（MOFs）中在多种应用中具有实际意义，例如气体储存和分离，因为不足的热量散发可能导致有害的影响。 尽管已有研究，但由于对控制热传导机制的理解不足，分子渗透对热传导的影响在许多MOFs中仍不明确。 在此，我们报告了沸石咪唑酯框架（ZIFs）中热传导特性的分子动力学研究。 我们研究了具有异常低热导率且温度依赖性趋势偏离许多晶体材料的Linde Type A拓扑ZIFs（ZIF-lta），尽管它们具有长程晶体秩序。 我们证明，热主要由平均自由路径与其波长相当的声子携带，类似于非晶固体中的扩散子，这是由于由包含大量金属中心的单元胞复杂性引起的强非谐性。 我们进一步表明，吸附的氢分子通过气体-气体或气体-框架相互作用增加了ZIFs的热导率，主要贡献是额外的振动模式。 我们的工作加深了对MOFs中热传导的基本理解，并提出了一种通过气体渗透来设计热传导的方法。 显示英文摘要

摘要： Thermal transport in metal-organic frameworks (MOFs) is of practical interest in diverse applications such as gas storage and separations, since insufficient heat dissipation can lead to detrimental effects. Despite investigations, influence of molecular infiltration on the heat transport remains unclear in many of MOFs due to poor understanding of mechanisms governing heat conductions. Here, we report molecular dynamics investigations of thermal transport properties in zeolitic imidazolate frameworks (ZIFs). We investigated Linde Type A topological ZIFs (ZIF-lta) exhibiting exceptionally low thermal conductivity with unusual trend of temperature dependence deviating from many crystalline materials, despite long-range crystalline order in them. We demonstrate that heat is predominantly carried by phonons with mean free paths comparable to their wavelengths, analogous to diffusons in amorphous solids owing to strong anharmonicity caused by complexity of unit cell consisting of a large number of metal centers. We further show that adsorbed hydrogen molecules increase thermal conductivity of ZIFs, mainly contributed by additional vibrational modes, as a result of gas-gas or gas-framework interactions. Our work advances fundamental understanding into the thermal transport in MOFs and suggests a means to engineer heat conduction via gas infiltrations.