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Title: Synthesis and X-ray absorption spectroscopy of potassium transition metal fluoride nanocrystals

Nanocrystals of KMF 3 (M = Mn–Ni) and K 3MF 6 (M = V, Fe) were synthesized via non-aqueous routes based on colloidal chemistry. The effect of a variety of parameters on the purity, size and quality of the nanocrystals was evaluated. Fluorides formed from mixtures of commercially available potassium trifluoroacetate and transition metal alkoxides, as opposed to existing methods based solely on trifluoroacetate precursors. Particles of KMF 3 in the range of several to tens of nanometers, were achieved. It was found here that methodologies based on hot injection of precursors often led to crystal sizes an order of magnitude smaller than those obtained from co-thermolysis as well as higher purity material. X-ray absorption spectroscopy revealed that M–F bond hybridization increased with transition metal d-electron count. On further probing of the Fe K and L edges, making use of different probing depths, KFeF 3 nanocrystals were found to have Fe II in the bulk, while the surface was rich in Fe III, but not as the product of oxidation. The developed protocols and lessons learned could be leveraged to rapidly devise synthetic methods for other alkali transition metal fluorides of interest.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ; ORCiD logo [1]
  1. Univ. of Illinois, Chicago, IL (United States). Dept. of Chemistry
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). The Molecular Foundry
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AC02-05CH11231; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
CrystEngComm
Additional Journal Information:
Journal Volume: 21; Journal Issue: 1; Journal ID: ISSN 1466-8033
Publisher:
Royal Society of Chemistry
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Illinois, Chicago, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1504756
Alternate Identifier(s):
OSTI ID: 1484315; OSTI ID: 1490791

Plews, Michael R., Yi, Tanghong, Lee, John, Chan, Emory, Freeland, John W., Nordlund, Dennis, and Cabana, Jordi. Synthesis and X-ray absorption spectroscopy of potassium transition metal fluoride nanocrystals. United States: N. p., Web. doi:10.1039/c8ce01349g.
Plews, Michael R., Yi, Tanghong, Lee, John, Chan, Emory, Freeland, John W., Nordlund, Dennis, & Cabana, Jordi. Synthesis and X-ray absorption spectroscopy of potassium transition metal fluoride nanocrystals. United States. doi:10.1039/c8ce01349g.
Plews, Michael R., Yi, Tanghong, Lee, John, Chan, Emory, Freeland, John W., Nordlund, Dennis, and Cabana, Jordi. 2018. "Synthesis and X-ray absorption spectroscopy of potassium transition metal fluoride nanocrystals". United States. doi:10.1039/c8ce01349g.
@article{osti_1504756,
title = {Synthesis and X-ray absorption spectroscopy of potassium transition metal fluoride nanocrystals},
author = {Plews, Michael R. and Yi, Tanghong and Lee, John and Chan, Emory and Freeland, John W. and Nordlund, Dennis and Cabana, Jordi},
abstractNote = {Nanocrystals of KMF3 (M = Mn–Ni) and K3MF6 (M = V, Fe) were synthesized via non-aqueous routes based on colloidal chemistry. The effect of a variety of parameters on the purity, size and quality of the nanocrystals was evaluated. Fluorides formed from mixtures of commercially available potassium trifluoroacetate and transition metal alkoxides, as opposed to existing methods based solely on trifluoroacetate precursors. Particles of KMF3 in the range of several to tens of nanometers, were achieved. It was found here that methodologies based on hot injection of precursors often led to crystal sizes an order of magnitude smaller than those obtained from co-thermolysis as well as higher purity material. X-ray absorption spectroscopy revealed that M–F bond hybridization increased with transition metal d-electron count. On further probing of the Fe K and L edges, making use of different probing depths, KFeF3 nanocrystals were found to have FeII in the bulk, while the surface was rich in FeIII, but not as the product of oxidation. The developed protocols and lessons learned could be leveraged to rapidly devise synthetic methods for other alkali transition metal fluorides of interest.},
doi = {10.1039/c8ce01349g},
journal = {CrystEngComm},
number = 1,
volume = 21,
place = {United States},
year = {2018},
month = {11}
}

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