TY - JOUR
T1 - Electronic structures and dehydrogenation properties of bimetallic amidoboranes
AU - Wang, Kun
AU - Zhang, Jian Guo
AU - Li, Tong
AU - Liu, Ying
AU - Zhang, Tonglai
AU - Zhou, Zun Ning
N1 - Publisher Copyright:
© 2015 Hydrogen Energy Publications, LLC.
PY - 2015/2/19
Y1 - 2015/2/19
N2 - Bimetallic amidoboranes (MM′AB, M and M′ denote different metals, respectively) are capable of improving the efficiency of dehydrogenation process and purity of released hydrogen compared to monometallic amidoboranes. In order to elucidate the reason behind this improvement, we perform a solid state Density Functional Theory (DFT) study on several bimetallic amidoboranes recently synthesized, NaMg(NH2BH3)3 (SMAB), Na2Mg(NH2BH3)4 (DSMAB), Na[Li(NH2BH3)2] (SLAB), and K2Mg(NH2BH3)4 (DKMAB). Whereas the crystal structure SMAB has not been obtained yet (the other three have been obtained experimentally), we apply the Monte Carlo method to simulate its crystal structure. Then the optimized crystal structures and electronic structures of MM′ABs have been determined for further studies of their thermodynamic properties and the initial dehydrogenation mechanisms. Two metals in MM'AB play totally different roles to improve the appearance of dehydrogenation. Moreover, the first dihydrogen bond of N-Hδ+ ... -δH-B prefers being formed between two neighboring [NH2BH3] groups rather than in the same [NH2BH3] molecule. The molecular dynamic study of the hydrogen diffusion at room temperature shows that H(B) atoms have faster speed than that of H(N) atoms caused by the bond strength and electronic structures. Generally, the diffusion rate of hydrogen is as the sequence of SMAB > SLAB > DKMAB > DSMAB.
AB - Bimetallic amidoboranes (MM′AB, M and M′ denote different metals, respectively) are capable of improving the efficiency of dehydrogenation process and purity of released hydrogen compared to monometallic amidoboranes. In order to elucidate the reason behind this improvement, we perform a solid state Density Functional Theory (DFT) study on several bimetallic amidoboranes recently synthesized, NaMg(NH2BH3)3 (SMAB), Na2Mg(NH2BH3)4 (DSMAB), Na[Li(NH2BH3)2] (SLAB), and K2Mg(NH2BH3)4 (DKMAB). Whereas the crystal structure SMAB has not been obtained yet (the other three have been obtained experimentally), we apply the Monte Carlo method to simulate its crystal structure. Then the optimized crystal structures and electronic structures of MM′ABs have been determined for further studies of their thermodynamic properties and the initial dehydrogenation mechanisms. Two metals in MM'AB play totally different roles to improve the appearance of dehydrogenation. Moreover, the first dihydrogen bond of N-Hδ+ ... -δH-B prefers being formed between two neighboring [NH2BH3] groups rather than in the same [NH2BH3] molecule. The molecular dynamic study of the hydrogen diffusion at room temperature shows that H(B) atoms have faster speed than that of H(N) atoms caused by the bond strength and electronic structures. Generally, the diffusion rate of hydrogen is as the sequence of SMAB > SLAB > DKMAB > DSMAB.
KW - Bimetallic amidoboranes
KW - Dehydrogenation mechanism
KW - First-principle study
KW - Hydrogen-storage
KW - Monte Carlo simulation
UR - http://www.scopus.com/inward/record.url?scp=84921863558&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2014.12.109
DO - 10.1016/j.ijhydene.2014.12.109
M3 - Article
AN - SCOPUS:84921863558
SN - 0360-3199
VL - 40
SP - 2500
EP - 2508
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 6
ER -
