Kong Jiajia, Li Dezhen, Liu Yuan, Liu Chang
College of Physics, Liaoning University, Shenyang, 110036, China.
School of Chemical Engineering and Technology, Sun Yat-Sen University, Zhuhai, 519082, China.
J Mol Model. 2025 May 13;31(6):158. doi: 10.1007/s00894-025-06383-y.
Porous ice with ultralow density has recently demonstrated remarkable hydrogen storage capacity. However, the thermal decomposition behavior of ultralow-density porous ice stored with H had not been investigated. In this work, the decomposition behavior of an ultralow-density porous ice, known as EMT, filled with varying amounts of H was studied using molecular dynamics (MD) simulations. It was found that hydrogen molecules can rapidly diffuse within the porous ice framework even at low temperatures. As the temperature increases, the diffusion of water molecules intensifies until the clathrate framework of HO breaks down. The decomposition temperature rises from 230 to 250 K at 1 bar as the number of H molecules increases from 192 to 1632 in a supercell of EMT containing 2304 HO molecules. Notably, the decomposition temperature further increases to 270 K at 1 bar when each 46 water cavity of EMT is occupied by a CH molecule. This reveals the decomposition mechanism of EMT porous ice stored with H and demonstrates that the stability of EMT porous ice can be significantly enhanced by encapsulating CH within 46 water cavities. These findings provide valuable insights into hydrogen storage in porous ice.
Thermal decomposition behaviors of the ultralow-density porous ice EMT stored with H were investigated by gradually increasing the temperature in steps of 10 K from 200 K at ambient pressure based on MD simulations. The consistent valence force field was employed to describe the intermolecular and intramolecular interactions of the system with NPT ensemble.
具有超低密度的多孔冰最近展现出了卓越的储氢能力。然而，储存有氢气的超低密度多孔冰的热分解行为尚未得到研究。在这项工作中，使用分子动力学（MD）模拟研究了一种称为EMT的超低密度多孔冰在填充不同量氢气时的分解行为。研究发现，即使在低温下，氢分子也能在多孔冰框架内快速扩散。随着温度升高，水分子的扩散加剧，直至水合物框架HO分解。在含有2304个HO分子的EMT超晶胞中，随着氢分子数量从192个增加到1632个，在1巴压力下分解温度从230 K升至250 K。值得注意的是，当EMT的每个46个水腔被一个CH分子占据时，在1巴压力下分解温度进一步升至270 K。这揭示了储存有氢气的EMT多孔冰的分解机制，并表明通过在46个水腔内封装CH可以显著提高EMT多孔冰的稳定性。这些发现为多孔冰中的氢储存提供了有价值的见解。
基于MD模拟，在环境压力下从200 K开始以10 K的步长逐渐升高温度，研究储存有氢气的超低密度多孔冰EMT的热分解行为。采用一致价力场来描述系统在NPT系综下的分子间和分子内相互作用。
