Internal Field 59Co NMR Study of Cobalt-Iron Nanoparticles During the Activation of CoFe2/CaO Catalyst for Carbon Nanotube Synthesis | Sciact - CRIS-system of Boreskov Institute of Catalysis

Internal Field 59Co NMR Study of Cobalt-Iron Nanoparticles During the Activation of CoFe2/CaO Catalyst for Carbon Nanotube Synthesis Conference Abstracts

Conference

255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water
18-22 Mar 2018 , New Orleans, Louisiana

Source

255th ACS National Meeting : Book of Abstracts
Compilation, American Chemical Society. New Orleans, LA.2018. 624 c.

Journal

Abstracts of Papers of the American Chemical Society
ISSN: 0065-7727

Output data

Year: 2018, Volume: 255, Article number : CATL-418, Pages count : 1

Authors

Andreev A.S. ^1,2 , Krasnikov D.V. ^1,4 , Kazakova M. ^1,4 , Lapina O.B. ^1,4 , Kusnetsov V.L. ^1,4 , d’Espinose de Lacaillerie J. ^2,3

Affiliations

1	Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia
2	ESPCI Paris, UMR CNRS SIMM, Paris, France
3	Université PSL, Paris, France
4	Novosibirsk State University, Novosibirsk, Russia

Funding (3)

1	Russian Foundation for Basic Research	17-53-150018
2	Federal Agency for Scientific Organizations	0303-2016-0002
3	French Embassy in Moscow

Obtaining stable metal nanoparticles is of high interest for various applications such as catalysis, batteries, supercapacitors and electro-magnetic devices. While nanometer particles are normally superparamagnetic at room temp., the confinement of Co results in a ferromagnetism that permits their characterization by NMR within their internal field, that is without the need for a parmanent magnet. This unusual mode of solid-state NMR spectroscopy is called internal field NMR (IF NMR). We illustrate the potential of the method within the context of multi-walled carbon nanotubes (MWCNT) synthesis. In that case, 59Co IF NMR provided original information about the structure, size, and shape anisotropy of the nanoparticles under near in-situ conditions. CoFe2/CaO catalysts for multi-walled carbon nanotubes (MWCNT) are characterized during the activation period (T = 670 C; C2H4/Ar = 1:1, 400 sccm) by internal field 59Co NMR. During this induction period, although C2H4 is already reacting, the MWCNT yield remains zero. The NMR spectra of the catalysts revealed the occurrence of several structural and magnetic species. Two samples quenched at different activation time contained, beside non-reacted pure metal Co particles, strong and weak ferromagnetic alloys. During activation, the pure Co metal content dropped and an increase of the ordering of the cobalt-iron alloy in the catalyst was evidenced thus revealing a multistage activation mechanism for the reaction. We propose this ordering process during the induction period to be an intermediate step between the strong ferromagnetic Co rich alloy and the weak ferromagnetic Fe rich one and that it favors the onset of MWCNTs growth.

Andreev A.S. , Krasnikov D.V. , Kazakova M. , Lapina O.B. , Kusnetsov V.L. , d’Espinose de Lacaillerie J.
Internal Field 59Co NMR Study of Cobalt-Iron Nanoparticles During the Activation of CoFe2/CaO Catalyst for Carbon Nanotube Synthesis
In compilation 255th ACS National Meeting : Book of Abstracts. – American Chemical Society., 2018. WOS AN

Published print:

Mar 1, 2018

Web of science:	WOS:000435537702363
Chemical Abstracts:	2018:446125

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