A computational study of MgmHn nanoclusters with n:m ≥ 2:1 for efficient hydrogen storage. Issue 6 (22nd November 2022)

• Record Type: Journal Article
• Authors: Shi, Dongjie; Ni, Youxuan; Li, Geng; Yan, Zhenhua; Zhao, Qing; Xie, Weiwei; Meng, Xiangfei; Chen, Jun
• Is Part Of: International journal of quantum chemistry. Volume 123:Issue 6(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-22
• Subjects: density functional theory -- efficient hydrogen storage -- fast hydrogen desorption -- hydrogen‐enriched magnesium hydride clusters -- magnesium nanoclusters; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.27058
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: Magnesium‐based hydrogen storage material (MgH2 ) has attracted much attention due to its high hydrogen storage density (7.6 wt%). However, the high hydrogen dissociation enthalpy and slow hydrogen dissociation rate in bulk Mg hinder its wide application in the efficient hydrogen storage. In the present work, we study the hydrogen adsorption and desorption reactions of Mg m H n ( m = 1–6) nanoclusters using density functional theory. From the global search for the configurations of Mg m H n nanoclusters, we found not only stable saturated Mg m H n ( n = 2 m ) nanoclusters, but four hydrogen‐enriched Mg m H n ( n : m > 2:1) nanoclusters, Mg3 H7, Mg4 H9, Mg5 H11, Mg6 H13, with the hydrogen storage density higher than 8.3 wt%. The electronic‐structure calculations indicate that the stability of the hydrogen‐enriched cluster gets relatively higher for larger nanocluster. The ab initio dynamics simulations shows that all hydrogen‐enriched clusters have very fast hydrogen dissociation rates, which is promising for the hydrogen dissociation at ambient temperature and pressure. This work provides valuable insights into the hydrogen storage mechanism of nano‐magnesium materials. Abstract : The saturated stable Mg m H2 m and oversaturated Mg m H2 m +1 clusters, Mg3 H7, Mg4 H9, Mg5 H11, Mg6 H13 with the hydrogen storage density higher than 8.3 wt%, are found in the global search of the stable configurations. It is found that the larger size of the oversaturated cluster has higher stability. The ab initio dynamics simulations show that all hydrogen‐enriched clusters have very fast hydrogen dissociation rates, which is promising for the hydrogen use at standard ambient temperature and pressure.