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Supplementary Information
Alkoxide-intercalated CoFe-layered double hydroxides as precursors
of colloidal nanosheet suspensions: structural, magnetic and
electrochemical properties
Gonzalo Abellán,a Jose A. Carrasco,a Eugenio Coronado,a,*, Jorge Romero,a María Varela,b,c
a Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán
2, 46980, Paterna, Valencia, Spain.
b Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge,
TN 37830-6071, USA.
c Universidad Complutense de Madrid, Dpt. Fisica Aplicada III & Instituto Pluridisciplinar.
Madrid 28040, Spain.
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry C.This journal is © The Royal Society of Chemistry 2014
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Contents
SI 1. Physical Characterization of CoFe-LDH synthesized via coprecipitation route.
SI 1.I. Chemical Composition.
SI 1.II. FT-IR Spectra.
SI 1.III. Thermogravimetric Analysis.
SI 1.IV. FESEM images of CoFe-LDH Cop.
SI 2. FESEM-EDS study of CoFe-LDH.
SI 3. AFM study of exfoliated CoFe-LDH.
SI 4. Magnetic properties of CoFe-LDH synthesized via coprecipitation route.
SI 5. Diffusional behaviour of CoFe-LDH: peak current (ip) vs. square root of scan rate ( 1/2) plots.
SI 6. Electrochemical properties of CoFe-LDH Cop.
SI 7. Comparison of LSV curves for CoFe-LDH and CoFe-LDH Cop in 0.1 M and 1 M KOH.
SI 8. Linear sweep voltammetry curves of CoFe-LDH.
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SI 1: Physical Characterization of CoFe-LDH synthesized via coprecipitation route.
SI 1.I: Chemical Composition.
Metallic atomic composition of bulk samples was determined by means of electron probe
microanalysis (EPMA) performed in a Philips SEM-XL30 equipped with an EDAX
microprobe. Carbon, hydrogen and nitrogen contents were determined by microanalytical
procedures using an EA 1110 CHNS-O elemental analyzer from CE Instruments. The
proposed chemical formula was estimated to be: [Co0.67Fe0.33(OH)2](CO3)0.16·0.2H2O; Co/Fe
= 2 / 1. (C,H,N, calc: 1.9, 2.3, 0; found: 1.56, 2.44, 0.14).
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SI 1.II: FT-IR Spectra.
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SI 1.III: Thermogravimetric Analysis.
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SI 1.IV: FESEM images of CoFe-LDH Cop.
FESEM images of the CoFe-LDH Cop sample show a wide distribution of sizes of several
hundred nanometers.
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SI 2. FE
(A and
EDS) im
(B), sho
discardi
ESEM-EDS
B) Field-em
mages of Co
owing the
ing the pres
S study of C
mission sca
oFe-LDH m
homogeneo
ence of seg
CoFe-LDH
anning elec
measured at
ous distribu
gregated pha
H.
ctron micros
t different m
ution of Co
ases.
scopy with
magnificatio
o (purple) a
elemental
ons can be o
and Fe (gre
mapping (F
observed in
een) in the
FESEM-
(A) and
sample,
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SI 3. AF
In order
have me
AFM hi
(B) the
Control
FM study o
r to further
easured sev
istograms o
correspond
experimen
of exfoliate
r determine
veral exfolia
of the exfoli
ing particle
t on SiO2 pr
d CoFe-LD
the lateral
ated CoFe-L
iated partic
-height.
repared by t
DH.
dimension
LDHs. The f
les in water
the same pr
ns and heigh
following F
r, depicting
rocedure wi
ht of our L
igure show
g the (A) pa
th its height
LDH nanosh
ws the corres
article-size d
t profile.
heets we
sponding
data and
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SI 4. M
(A) The
almost l
observe
CoFe-L
intrinsic
suscepti
ca. 11 K
of size
platelets
depicted
Magnetic pro
e temperatu
linear incre
ed for the C
LDH Cop),
c cooperati
ibility revea
K, 4 K highe
effects, wit
s in contra
d in the FES
operties of
ure-dependen
ase above c
CoFe-LDH
the drop o
ive magnet
aled a temp
er that that
th an averag
ast with th
SEM measu
CoFe-LDH
nt magnetic
ca. 25 K for
sample (F
bserved be
tism in the
perature for
exhibited by
ge size of s
e homogen
urements.
H synthesiz
c susceptibi
r the CoFe-
igure 4 ma
elow 20 K
e LDH lay
the onset o
y the pure C
several hun
neous distri
zed via copr
ility, , repo
LDH Cop s
ain text). In
defining a
yers. (B) T
of the spont
CoFe-LDH
ndred nanom
ibution of
recipitation
orted as,
sample, whi
n both case
maximum
The measur
aneous mag
(Table 1 m
meters for th
sizes for t
n route.
versus T s
ilst no incre
es (CoFe-L
correspond
rements of
gnetization
main text), in
the CoFe-LD
the CoFe-L
hows an
ease was
LDH and
ds to the
f the ac
(TM) of
ndicative
DH Cop
LDH, as
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SI 5: Diffusional behaviour of CoFe-LDH: peak current (ip) vs. square root of scan rate ( 1/2) plots.
Cyclic voltammograms of CoFe-LDH at different scan rates (left) indicating the fitted peaks.
Plot of the peak current vs. square root of scan rate ( 1/2) for peaks P1 and P2 (right).
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SI 6: El
(A) CV
discharg
densitie
lectrochem
V curves at
ge curves a
es. (D) Spec
mical proper
t various s
and (C) spe
cific capacit
rties of CoF
can rates i
ecific capac
ance vs. cyc
Fe-LDH Co
in 6 M KO
citance of th
cle number
op
OH aqueou
he material
at a current
us solution.
at differen
t density of
(B) Galva
nt discharge
40 Ag-1.
anostatic
e current
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SI 7. Comparison of LSV curves for CoFe-LDH and CoFe-LDH Cop in 0.1 M and 1 M
KOH.
The direct comparison between CoFe-LDH and CoFe-LDH Cop leads to a similar behaviour
strongly dependent on pH, with some differences probably arising from the extrinsic sources
as well as the different particle size and/or morphology. Further studies are needed in order to
clarify these differences on the electrocatalytic behaviour.
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SI 8: Linear sweep voltammetry curves of CoFe-LDH.
LSV curves obtained with freshly prepared CoFe-LDH and 10000 s after use under
chronoamperometric measurements at 0.83 V (0.1 M) and 0.75 V (1 M) vs ENH.