Concerted Growth and Ordering of Cobalt Nanorod Arrays as Revealed by Tandem in Situ SAXS-XAS Studies.
The molecular and ensemble dynamics for the growth of hierarchical supercrystals of cobalt nanorods have been studied by in situ tandem X-ray absorption spectroscopy-small-angle X-ray scattering (XAS-SAXS). The supercrystals were obtained by reducing a Co(II) precursor under H2 in the presence of a long-chain amine and a long-chain carboxylic acid. Complementary time-dependent ex situ TEM studies were also performed. The experimental data provide critical insights into the nanorod growth mechanism and unequivocal evidence for a concerted growth-organization process. Nanorod formation involves cobalt nucleation, a fast atom-by-atom anisotropic growth, and a slower oriented attachment process that continues well after cobalt reduction is complete. Smectic-like ordering of the nanorods appears very early in the process, as soon as nanoparticle elongation appears, and nanorod growth takes place inside organized superlattices, which can be regarded as mesocrystals.
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Benoit
B
Cormary
Tao
T
Li
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Nikos
N
Liakakos
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Laurent
L
Peres
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Pier-Francesco
PF
Fazzini
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Thomas
T
Blon
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Marc
M
Respaud
A Jeremy
AJ
Kropf
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Bruno
B
Chaudret
School of Chemical Engineering, Purdue University , 480 Stadium Mall Drive, West Lafayette, Indiana 47097, United States.
Jeffrey T
JT
Miller
Elizabeth A
EA
Mader
Université de Toulouse , INSA, UPS, LPCNO, CNRS-UMR5215, 135 avenue de Rangueil, 31077 Toulouse, France.
Katerina
K
Soulantica