In situ formed ultrafine NbTi nanocrystals from a NbTiC solid-solution MXene for hydrogen storage in MgH2

Zeyi Wang, Xuelian Zhang, Zhuanghe Ren, Yong Liu, Jianjiang Hu, Haiwen Li, Mingxia Gao, Hongge Pan, Yongfeng Liu

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14 Citations (Scopus)

Abstract

A novel 2D layered NbTiC solid-solution MXene was synthesized from its MAX phase via a wet chemical etching process. While ball milling the NbTiC MXene with MgH2, ultrafine bimetal NbTi nanocrystals were formed in situ with a grain size of 5 nm, which offer highly stable catalytic activity for the hydrogen storage reaction of MgH2. The MgH2-9 wt% NbTiC sample starts releasing hydrogen from 195 °C, which is 80 °C lower than that for the additive-free sample. At 250 °C, it releases approximately 5.8 wt% H2 within 30 min, and the fully dehydrogenated sample takes up 4.0 wt% H2 within 15 min even at 50 °C under 50 bar H2 pressure. DFT calculations reveal a charge transfer process from Ti atoms to Nb atoms in the NbTi cluster and a lower absolute value of the adsorption energy of H2 on NbTi. This would presumably benefit both the breakage of Mg-H bonding and the detachment of H2 from the NbTi surface, and consequently lead to good catalytic activity.

Original languageEnglish
Pages (from-to)14244-14252
Number of pages9
JournalJournal of Materials Chemistry A
Volume7
Issue number23
DOIs
Publication statusPublished - Jan 1 2019

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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