Open AccessSynthesis of Metal Nanoparticles and Metal Fluoride Nanoparticles from Metal Amidinate Precursors in 1‐Butyl‐3‐Methylimidazolium Ionic Liquids and Propylene Carbonate
Author(s) -
Schütte Kai,
Barthel Juri,
Endres Manuel,
Siebels Marvin,
Smarsly Bernd M.,
Yue Junpei,
Janiak Christoph
Publication year - 2017
Publication title -
chemistryopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 29
ISSN - 2191-1363
DOI - 10.1002/open.201600105
Subject(s) - ionic liquid , tetrafluoroborate , hexafluorophosphate , trifluoromethanesulfonate , nanoparticle , propylene carbonate , powder diffraction , transition metal , chemistry , metal , inorganic chemistry , nuclear chemistry , materials science , catalysis , electrochemistry , crystallography , organic chemistry , nanotechnology , electrode
Decomposition of transition‐metal amidinates [M{MeC(N i Pr) 2 } n ] [M(AMD) n ; M=Mn II , Fe II , Co II , Ni II , n= 2; Cu I , n= 1) induced by microwave heating in the ionic liquids (ILs) 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]), 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIm][PF 6 ]), 1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate (triflate) ([BMIm][TfO]), and 1‐butyl‐3‐methylimidazolium tosylate ([BMIm][Tos]) or in propylene carbonate (PC) gives transition‐metal nanoparticles (M‐NPs) in non‐fluorous media (e.g. [BMIm][Tos] and PC) or metal fluoride nanoparticles (MF 2 ‐NPs) for M=Mn, Fe, and Co in [BMIm][BF 4 ]. FeF 2 ‐NPs can be prepared upon Fe(AMD) 2 decomposition in [BMIm][BF 4 ], [BMIm][PF 6 ], and [BMIm][TfO]. The nanoparticles are stable in the absence of capping ligands (surfactants) for more than 6 weeks. The crystalline phases of the metal or metal fluoride synthesized in [BMIm][BF 4 ] were identified by powder X‐ray diffraction (PXRD) to exclusively Ni‐ and Cu‐NPs or to solely MF 2 ‐NPs for M=Mn, Fe, and Co. The size and size dispersion of the nanoparticles were determined by transmission electron microscopy (TEM) to an average diameter of 2(±2) to 14(±4) nm for the M‐NPs, except for the Cu‐NPs in PC, which were 51(±8) nm. The MF 2 ‐NPs from [BMIm][BF 4 ] were 15(±4) to 65(±18) nm. The average diameter from TEM is in fair agreement with the size evaluated from PXRD with the Scherrer equation. The characterization was complemented by energy‐dispersive X‐ray spectroscopy (EDX). Electrochemical investigations of the CoF 2 ‐NPs as cathode materials for lithium‐ion batteries were simply evaluated by galvanostatic charge/discharge profiles, and the results indicated that the reversible capacity of the CoF 2 ‐NPs was much lower than the theoretical value, which may have originated from the complex conversion reaction mechanism and residue on the surface of the nanoparticles.