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Title: Impact of initial catalyst form on the 3D structure and performance of ball-milled Ni-catalyzed MgH 2 for hydrogen storage

Although it has been shown that the hydrogen storage kinetics of metal hydrides can be significantly improved by the addition of transition metal-based catalysts, relatively little attention has been paid to the impact that the form in which these catalysts are introduced during synthesis has on the resulting structure and how this alters performance. Two mixtures of MgH 2 doped with Ni were prepared via high-energy ball-milling under identical conditions, one using a pure Ni nanopowder catalyst and the other using anhydrous NiCl 2. The resulting Ni catalyst particles of the NiCl 2-doped material were 10-100 times smaller, as well as more uniform in size and shape. Electron tomography revealed that the additive form also altered its incorporation and 3D spatial distribution, with Ni particles limited to the outer surface in the NiCl 2-doped case. The significantly lower desorption performance measured in the NiCl 2-doped material is attributed to regions of MgCl 2 acting as barriers between the MgH 2 and Ni, hindering the ability of the latter to effectively catalyze the reactions. Finally, this work demonstrates the hazards in assuming different catalyst forms produce similar final structures and highlights the potential of catalyst form as a synthesis tool formore » optimizing the material structure and performance.« less
Authors:
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [5]
  1. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Materials Science
  2. HRL Laboratories, LLC, Malibu, CA (United States)
  3. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Metallurgical Engineering
  4. Argonne National Lab. (ANL), Argonne, IL (United States)
  5. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Materials Science; Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
FC36-05GO15064; AR0000173; 0933778; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
International Journal of Hydrogen Energy
Additional Journal Information:
Journal Volume: 42; Journal Issue: 8; Journal ID: ISSN 0360-3199
Publisher:
Elsevier
Research Org:
Univ. of Illinois, Urbana-Champaign, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); Japanese Ministry of Education, Culture, Sports, Science and Technology
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 25 ENERGY STORAGE; 36 MATERIALS SCIENCE; Metal hydrides; Hydrogen storage; Transmission electron microscopy; Electron tomography; In situ TEM; High-energy ball-milling
OSTI Identifier:
1362070
Alternate Identifier(s):
OSTI ID: 1398537