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www.jm .com.b
A ailable
online
a
www.sciencedi ec .com
O iginal
a icle
E ec
o
magne i e
ans o ma ions
on
deg ada ion
e ficiency
o
ce ium
dioxide-magne i e
composi e
Y onna
Ji asko aa,∗,
Ji i
Bu sika,
Jakub
Ede e b,
Pa el
Janosb,
Jan
Ju icac,
Ji i
Lunacekd,
Ond ej
Zi o skyd
aCEITEC
IPM,
Ins i u e
o
Physics
o
Ma e ials,
AS
CR, ˇ
Ziˇ
zko a
22,
616
62
B no,
Czech
Republic
bFacul y
o
he
En i onmen ,
Uni e si y
o
Jan
E angelis a
Pu kynˇ
e,
K álo a
V´
yˇ
sina
7,
400
96
Ús í
nad
Labem,
Czech
Republic
cRegional
Ma e ials
Science
and
Technology
Cen e,
Vˇ
SB
–
Technical
Uni e si y
o
Os a a,
17.
Lis opadu
2172/15,
708
00
Os a a-Po uba,
Czech
Republic
dDepa men
o
Physics,
Vˇ
SB
–
Technical
Uni e si y
o
Os a a,
17.
Lis opadu
2172/15,
708
00
Os a a-Po uba,
Czech
Republic
a
i
c
l
e
i
n
o
A icle
his o y:
Recei ed
26
Decembe
2019
Accep ed
18
Feb ua y
2020
A ailable
online
28
Feb ua y
2020
Keywo ds:
CeO2
I on
oxide
Mic os uc u e
Magne ic
p ope y
Mössbaue
spec oscopy
Deg ada ion
e ficiency
a
b
s
a
c
P esen
in es iga ions
a e
ocused
on
syn hesis
o
magne i e/ce ium
dioxide
eac i e
so -
ben s
in
a ious
weigh
a ios
o
componen s
and
hei
cha ac e iza ion
o
chemical
and
magne ic
p ope ies.
The
mo phology
and
changes
in
magne ic
ans o ma ions
in
depen-
dence
on
composi ion
a e
ollowed
by
elec on
mic oscopy,
X- ay
di ac ion,
Mössbaue
spec oscopy
and
magne ic
measu emen s
a
oom
and
low
empe a u es.
Deg ada ion
e ficiency
is
e alua ed
om
a
decomposi ion
o
he
o ganophospho us
pes icide
pa a hion
me hyl
using
p epa ed
eac i e
so ben s.
The
expe imen al
esul s
e eal
ha
he
deg a-
da ion
e ficiency,
exp essed
by
a e
cons an
(mol/h)
in
dependence
on
amoun
o
ce ium
dioxide
con en
( ol.%),
is
independen
on
kind
o
i on
oxide
bu
inc eases
wi h
ce ium
diox-
ide
con en .
On
he
con a y,
sa u a ion
and
emanen
magne iza ions
a e
highly
sensi i e
o
ela i e
a io
o
i on
oxides;
magne i e,
maghemi e
and
hema i e,
o igina ing
om
he
ini ial
magne i e
ans o ma ions
in
dependence
on
sample
composi ion.
©
2020
The
Au ho s.
Published
by
Else ie
B.V.
This
is
an
open
access
a icle
unde
he
CC
BY-NC-ND
license
(h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/).
1.
In oduc ion
The
a e
ea h
ce ium
oxide
o
ce ium
dioxide
belongs
p esen ly
o
equen ly
s udied
opic.
I
is
p epa ed
by
a ious
syn he ic
p ocedu es
and
cha ac e ized
wi h
la ge
numbe
o
expe imen al
me hods.
Among
echnologies,
e.g.,
sol-gel
me hods,
homogeneous
hyd olysis
[1],
hyd o he mal
syn he-
∗Co esponding
au ho .
E-mail:
[email p o ec ed]
(Y.
Ji asko a).
sis
[2,3],
p ecipi a ion
me hods
using
oxala e,
ammonium
hyd oxide
and
ammonium
ca bona e
[4–6]
can
be
men ioned.
Ce ium
dioxide
and
ce ium
dioxide-based
composi es
a e
used
in
di e en
echnological
applica ions
[7].
These
include
a
wide
ange
o
ca aly ic
applica ions
[8],
solid
oxide
uel
cells
[9,10],
oxygen
senso s
[11],
glass-polishing
[12],
an
ul a io-
le
abso ben ,
e.g.,
o
cosme ic
use
[13,14],
eac i e
so ben s
[15–17].
The
las
decade
assumes
also
impo ance
in
he
medical
field.
Thanks
o
ce ium
dioxide
sel
egene a ing
an ioxidan
p ope ies,
i
ep esen s
a
p omising
an ioxidan
o
healing
nume ous
un ea able
oxida i e-s ess- ela ed
diseases
[18–21].
h ps://doi.o g/10.1016/j.jm .2020.02.068
2238-7854/©
2020
The
Au ho s.
Published
by
Else ie
B.V.
This
is
an
open
access
a icle
unde
he
CC
BY-NC-ND
license
(h p://
c ea i ecommons.o g/licenses/by-nc-nd/4.0/).
4432
j
m
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Ce ium
dioxide
is
he
mos
widely
known
compound
o
ce ium.
I
c ys allizes
in
fluo i e
c ys al
s uc u e
wi h
cc
uni
cell,
space
g oup
Fm3m.
I
has
pale
yellow
colou
and
is
p ac ically
insoluble
in
wa e
and
only
mode a ely
soluble
in
s ong
mine al
acids.
I
can
abso b
small
amoun
mois u e
and
ca bon
dioxide
om
he
a mosphe e.
The
p ope y
ha
is
equen ly
discussed
a
p esen
is
i s
easy
o ma ion
o
oxy-
gen
acancies
which
should
be
a
eason
o
i s
e omagne ic
beha iou
in
he
nanosized
s a e
(pa icle
dimensions
<
15
nm)
[22,23]
in
spi e
o
i s
diamagne ic
s a e
in
he
bulk
o m.
Ge
and
co-au ho s
[24]
e ified
expe imen ally
and
heo e ically
ha
oxygen
acancies
cause
an
inc ease
in
magne iza ion
o
nanopa icles
compa ed
o
bulk
samples
due
o
e ec -
ing
he
su ounding
o
elec ons
leading
o
an
inc ease
in
magne ic
momen s
o
pa icles.
The
oom- empe a u e
e -
omagne ism
o
ce ium
dioxide
is
also
influenced
by
ei he
goal-di ec ed
ansi ion
me al
doping
[25–28]
o
by
magne ic
impu i ies
[29,30].
P e ious
s udies
e ealed
an
unusual
abili y
o
ce ium
oxide
o
des oy
oxic
o ganophospha e
compounds;
his
abil-
i y
demons a es
no
only
in
pu e
nano-ce ium
dioxide,
bu
also
in
magne ically
sepa able
composi es
based
on
Fe-oxides
and
CeO2.
Va ious
chemical
p ocedu es
we e
examined
and
sui able
composi ions
and
he mal
ea men s
a e
sea ched
and
s udied
[15,31,32].
P esen
wo k
is
also
de o ed
o
magne ically
sepa able
so -
ben s
based
on
i on
and
ce ium
oxides
o
di e en
mu ual
olume
a ios
and
exposed
o
he
same
calcina ion
ea -
men .
The
mic os uc u al
and
physical
cha ac e is ics
o
hese
sys ems
ha e
been
s udied
in
o de
o
co ela e
hem
wi h
he
sensing
p ope ies
owa ds
haza dous
o ganophos-
pha es.
2.
Expe imen al
2.1.
Ma e ials
and
sample
p epa a ion
The
inpu
ma e ials
o
he
sample
p epa a ions
we e
pu -
chased
as
eagen -g ade
chemicals
om
Sigma
Ald ich
(S einheim,
Ge many).
The
ce ium
ca bona e
was
p epa ed
om
he
comme cial
Ce(NO3)3.6H2O
(pu i y
99.9%)
and
NH4HCO3(pu i y
99.5%)
by
p ecipi a ion
me hod
published
elsewhe e
[15].
B iefly,
he
ca bona e
p ecu so
was
p e-
pa ed
by
p ecipi a ion
o
an
aqueous
solu ion
o
Ce(NO3)3
(0.2
mol
L−1)
wi h
an
excess
o
NH4HCO3(0.5
mol
L−1)
unde
s i ing.
A e
he
p ecipi a ion
p ocess,
he
agi a ion
con in-
ued
o
one
mo e
hou
and
he
p ecipi a e
was
le
in
he
solu ion
un il
he
nex
day.
The
p ecipi a e
was
sepa a ed
by
fil a ion,
washed
wi h
deionized
wa e
and
d ied
o e nigh
a
110 ◦C.
Subsequen ly
he
adequa e
mass
o
ce ium
ca bon-
a e
and
a ificial
magne i e
(Fe3O4pa icle
size
50–100
nm)
was
mechanically
mixed
in
a ios
om
0/100
up
o
50/50
(CeO2/Fe3O4).
The
mix u es
o
ce ium
ca bona e/Fe3O4we e
subjec ed
o
annealing
p ocess
a
500 ◦C
o
2
h
in
ai
a mo-
sphe e.
Du ing
annealing
ce ium
ca bona e
ans o ms
in o
ce ium
oxide
(CeO2).
2.2.
Scanning
and
ansmission
elec on
mic oscopy,
X- ay
di ac ion,
pa icle
size
analyze
The
mo phology
o
samples
we e
ollowed
by
TESCAN
LYRA
3XMU
FEG/SEM
scanning
elec on
mic oscope
a
accele a ing
ol age
o
20
kV,
equipped
wi h
an
X-Max80
Ox o d
Ins u-
men s
de ec o
o
ene gy-dispe si e
X- ay
(EDX)
analysis.
FEI
Ti an
Themis
60–300
cubed
high
esolu ion
ansmission
elec-
on
mic oscope
wi h
a
high
sensi i i y
EDX
sys em
(0.7
s ad
solid
angle)
ope a ing
a
300
kV
was
used
o
selec ed
samples
o
see
hei
mo phology
in
mo e
de ails.
X’PERT
PRO
di ac ome e
(Panaly ical)
equiped
wi h
Co
K␣
adia ion
(␭
=0.17902
nm)
was
used
o
di ac og am
measu e-
men s
in
he
ange
o
2
=
20◦–135◦,
s eps
=
0.01◦,
and
ime/s ep
5
s.
Rie eld
s uc u e
efinemen
me hod
[33]
using
he
High-
Sco e
Plus
p og am
and
he
ICSD
da abase
[34]
we e
applied
o
analyze
he
ela i e
abundance
o
phases
(A)
and
hei
basic
pa ame e s,
la ice
cons an
(a)
and
mean
mic o-domain
size
(d).
Pa icle-size
dis ibu ion
was
measu ed
by
lase
di ac ion
pa icle
size
analyze
Mas e Size
3000,
Mal e n
Ins umen s
L d.
2.3.
Magne ic
and
Mössbaue
measu emen s
Room
empe a u e
magne ic
measu emen s
in
an
applied
ex e nal
field
o
±1600
kA/m
(±2
T)
we e
pe o med
using
ib a ing
sample
magne ome e
(VSM)
EZ9
(Mic osense,
Massachuse s,
USA).
This
equipmen
was
used
also
o
measu emen s
o
he
ini ial
( i gin)
cu e,
MVIR(H),
and
magne iza ions
a
inc easing
(MUP)
and
dec easing
(MDOWN)
posi i e
magne ic
fields.
These
cha ac e is-
ics
a e
needed
o
de e mina ion
o
he
Henkel
plo :
M(H)
=
MVIR(H)
−
(MUP(H)
+
MDOWN(H))/2.
A
physical
p ope y
measu emen
sys em
(PPMS,
Model
P935A,
San
Diego,
USA)
quan um
design
was
applied
o
mea-
su emen s
o
hys e esis
loops
wi h
maximal
magne ic
field
o
±4000
kA/m
(±5
T)
and
ze o-field-cooled
(ZFC)
and
field-
cooled
(FC)
cu es
in
he
magne ic
field
o
8
kA/m
and
in
he
empe a u e
ange
(2–293
K).
Mössbaue
spec oscopy
(MS)
measu emen s
we e
done
in
ansmission
geome y
a
oom
empe a u e
using
a57Co
(Rh)
sou ce.
Calib a ion
o
he
eloci y
scale
was
pe o med
wi h
␣-Fe
a
RT
and
he
isome
shi s
a e
gi en
wi h
espec
o
i s
Mössbaue
spec um.
All
spec a
we e
e alua ed
using
he
ansmission
in eg al
app oach
in
he
p og am
CONFIT
[35].
The
expe imen al
poin s
we e
analysed
by
double-
and
single-line
componen s
yielding
alues
o
isome
shi
(ı)
and
quad upole
spli ing
().
The
ela i e
ep esen a ion
o
hese
subcomponen s
is
deno ed
by
A.
2.4.
Deg ada ion
e ficiency
Deg ada ion
e ficiency
was
de e mined
om
pa a hion
me hyl
(PM)
decomposi ion
in o
4-ni o enol
(FN);
see
Re .
[15]
o
mo e
de ails.
The
simple
eac ion
PM⇒FN
is
assumed
and
kine ics
o
such
eac ion
is
ollowed
ei he
on
a
weigh
loss
j
m
a
e
e
s
e
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.
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4433
Fig.
1
–
Sample
o
nominal
composi ion
Fe3O4+10
w .%
Ce2(CO3)3a e
calcina ion
ea men ;
le
panel
–
a ea
EDX
analyses
om
he
sp ead
powde ,
igh
panel
–
local
analyses
om
indi idual
cons i uen s.
The
ob ained
composi ions
(in
a .%)
a e
shown
below.
Fig.
2
–
Mo phology
as
seen
in
SEM,
seconda y
elec ons
(a)
and
XRD
di ac og am
(b)
o
magne i e
in
he
ini ial
s uc u al
s a e.
o
PM
o
an
inc ease
o
FN
amoun .
Unde
p esump ion
ha
no
o he
eac ion
exis s
he
loss
o
PM
should
be
equal
o
he
inc ease
o
FN.
This
was
alid
in
p esen
s udy.
3.
Resul s
and
discussion
3.1.
Mo phology,
phase
and
chemical
composi ion
Chemical
analysis
was
done
by
EDX
in
SEM
on
powde s
sp ead
on
a
conduc i e
ape.
Se e al
a eas
we e
selec ed
a
each
sam-
ple
and
he
in eg al
alues
we e
measu ed.
Along
wi h
la ge
a ea
analyses,
he
poin
EDX
analyses
o
indi idual
phases
we e
measu ed
as
well.
As
an
example,
he
sample
o
nom-
inal
composi ion
Fe3O4+10
w .%
Ce2(CO3)3a e
calcina ion
ea men
(500 ◦C/2
h/ai )
is
shown
in
Fig.
1.
To
ollow
changes
in
phase
composi ion
o
he
mixed
samples
a e
calcina ion
ea men ,
bo h
inpu
powde s,
i.e.
magne i e
and
ce ium
ca bona e,
we e
also
ea ed
sepa a ely
by
he
same
calcina ion
pa ame e s.
The
mo phology
o
ini ial
magne i e
is
seen
in
Fig.
2a
and
X- ay
di ac og am
anal-
ysed
using
ICSD
20596
da a
shee
is
depic ed
in
Fig.
2b.
The
4434
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Fig.
3
–
Mo phology
as
seen
in
SEM,
seconda y
elec ons
(a)
and
XRD
di ac og am
(b)
o
magne i e
a e
calcina ion
ea men
a
500 ◦C/2
h/ai .
calcina ion
ea men
a
500 ◦C
o
2
h
in
ai
did
no
b ing
any
isible
changes
in
mo phology
as
seen
in
Fig.
3a.
Ne -
e heless
he
XRD
measu emen
(Fig.
3b)
yielded
a
mix u e
o
h ee
Fe-oxides,
namely
hema i e,
␣-Fe2O3, maghemi e,
␥-
Fe2O3,
and
ini ial
magne i e
Fe3O4analysed
using
da a
shee s
15840,
35643,
and
20596,
espec i ely.
The
calcina ion
ea men
has
ans o med
ce ium
ca bon-
a e
in o
ce ium
dioxide
o med
by
hin
ela i ely
la ge
pla es
seen
in
Fig.
4a
simul aneously
wi h
i s
di ac og am
in
Fig.
4b
confi ming
pu e
ce ium
oxide
analysed
by
28753
ICSD
da a
shee .
The
ela i e
a ios
o
oxide
phases
measu ed
by
XRD
a e
summa ised
in
dependence
on
he
ini ial
nominal
sam-
ple
composi ion
in
Table
1.
The
esul s
show
p edominan ly
magne i e
ans o ma ion
du ing
calcina ion
ea men .
EDX
elemen al
mapping
in
TEM
was
used
o
wo
selec ed
samples
(S5
and
S9)
o
isualize
quali a i ely
elemen s
dis-
ibu ion.
In
bo h
samples
(Fig.
5a,b)
we
could
obse e
la ge
Ce- ich
oxides
and
fine
Fe- ich
oxides
wi h
almos
no
chem-
ical
in e mixing
and
wi h
mo phology
simila
o
he
ini ial
s a e.
The
same
image
was
ound
in
o he
mixed
samples:
he
mo phology
and
lay-ou
was
simila
o
ha
seen
in
Fig.
1
igh .
The
pa icle
size
dis ibu ion
is
depic ed
in
Fig.
6.
The
sam-
ple
wi h
he
lowes
ce ium
dioxide
con en
(S4)
ollows
he
dis ibu ion
o
Fe-oxide
pa icles.
A
highe
ce ium
dioxide
con en s
he
peaks
o
dis ibu ions
ollow
ei he
peaks
co -
esponding
o
Fe-
and
Ce-oxides
o
he
isible
b oadening
o
dis ibu ions
a e
p esen
eflec ing
pa icle
agglome a ions.
The
analysis
o
XRD
pa e ns
has
yielded
he
size
o
mic odomains
o
ce ium
dioxide
a ying
be ween
8
and
10
nm,
while
hose
o
Fe-oxide
phases
was
app oxima ely
en
imes
la ge .
The
la ice
pa ame e s
o
indi idual
phases
in
he
sam-
ples
sligh ly
fluc ua ed
wi hin
he
ange
o
expe imen al
e o .
No
sys ema ic
elonga ion
o
con ac ion
o
la ice
pa ame e s
indica e
subs i u ion
o
Fe3+(Fe2+)
in
CeO2o
Ce4+ in
Fe-oxide
phases.
The
samples
S5
and
S7
ha e
shown
highe
con en s
o
magne i e
and
maghemi e
bu
a
eason
o
i
is
a
p esen
unclea .
3.2.
Mac o-
and
mic omagne ic
p ope ies
The
magne ic
measu emen s
a
oom
empe a u e
we e
used
o
de e mina ion
o
basic
magne ic
pa ame e s,
sa u a ion
and
emanen
magne iza ions
and
coe ci i y
and
pa ame-
e s
needed
o
Henkel
plo s
[36].
Hys e esis
loops
including
de ail
a
low
magne ic
fields
a e
shown
in
Fig.
7
o
ini ial
magne i e
(S1),
magne i e
a e
calcina ions’
ea men
(S2)
in
he
le
panel
and
hose
o
ce ium
dioxide
(S3)
in
he
igh
panel.
The
cu e
o
ce ium
dioxide
consis s
o
e omag-
ne ic
con ibu ion
well
isible
in
de ail
and
he
diamagne ic
con ibu ion
eflec ed
by
dec easing
magne isa ion
a
highe
magne ic
fields
due
o
a
nega i e
magne ic
suscep ibili y.
A
dec ease
in
sa u a ion
magne iza ion
o
he
S2
sample
is
due
o
ans o ma ion
o
magne i e
in o
mainly
haema i e
con-
ibu ing
wi h
i s
low
alue
o
sa u a ion
magne iza ion.
The
hys e esis
loops
o
he
mixed
samples
a e
p esen ed
he e
by
means
o
hei
magne ic
cha ac e is ics
shown
in
dependence
on
sample
composi ion
in
Fig.
8.
A
low
sp ead
o
he
coe ci i y
alues
in
he
samples
co -
esponds
o
he
simila
mo phology
o
he
samples
seen
in
SEM
mic og aphs.
On
he
o he
hand,
he
non-mono onic
changes
in
sa u a ion
and
emanen
magne iza ions
ollow
changes
in
he
Fe-oxide
ep esen a ion.
The
highe
ela i e
ep esen a ion
o
magne i e
and
maghemi e
s.
haema i e
in
he
samples
S5
and
S7
(Fig.
8
uppe
panel)
ma kedly
influence
he
magne iza ion.
While
haema i e
is
weakly
e omagne ic
o
sa u a ion
magne iza ion
0.3
Am2/kg
a
oom
empe a u e,
he
magne i e
and
maghemi e
a e
e imagne ic
yielding
isi-
bly
highe
alues
o
sa u a ion
magne iza ion
anges
be ween
60
up
o
100
Am2/kg
[37].
Thei
highe
con en
in
hese
samples
con ibu es
o
inc ease
in
magne iza ion.
The
same
endency
is
documen ed
in
Henkel
plo s
in
Fig.
9
ep esen ing
he
abo e
men ioned
o mula
M(H)
g aphically.
The
nega i e
dependences
documen
p e ailing
magne ic
dipola
(magne-
os a ic
dipole-dipole)
in e ac ions.
They
a e
p oduced
by
he
magne ic
momen
o
each
g ain
wi h
p e ailing
influence
o
he
Fe-oxides.
The
highes
peak
in ensi y
o
he
M(H),
−4.87
Am2/kg,
was
ob ained
o
he
ini ial
magne i e
(S1)
sam-
ple.
As
in
p e ious
obse a ions,
he
in ensi y
o
peaks
o
he
S5
and
S7
samples
abundan
in
magne i e
and
maghemi e
a e
highe
compa ed
o
he
o he
mixed
composi ions.
The
eason
o
hese
“anomalies”
is
unknown
in
his
momen .
I
can
be
only
specula ed
ha
i
could
come
o
an
un hough -o
condi ions
du ing
calcina ions
ea men .
The
Mössbaue
spec oscopy
was
applied
and
he
phases
and
hype fine
in e ac ions
analysed
o
comple e
mac oscopic
magne ic
p ope ies.
The
selec ed
Mössbaue
spec a
mea-
su ed
a
oom
empe a u e
a e
shown
in
Fig.
10.
The
spec a
j
m
a
e
e
s
e
c
h
n
o
l
.
2
0
2
0;9(3):4431–4439
4435
Fig.
4
–
Mo phology
as
seen
in
SEM,
seconda y
elec ons
(a)
and
XRD
di ac og am
(b)
o
ce ium
dioxide
ob ained
om
he
ce ium
ca bona e
a e
calcina ions’
ea men
a
500 ◦C/2
h/ai .
Table
1
–
Phase
composi ion
o
samples
de e mined
by
XRD
and
Mössbaue
phase
analysis
(MS,
only
e omagne ic
phases).
Nominal
composi ion
Sample
Me hod
Fe3O4␣-Fe2O3␥-Fe2O3␣-FeOOH
CeO2
w .%
Fe3O4S1 XRD
100.0
MS
74.5
18.7
5.0
Fe3O4/500 ◦C/2
h/ai S2 XRD
3.0
67.9
29.1
MS
8.1
66.8
22.6
1.7
CeO2(Ce2(CO3)3)/500 ◦C/2
h/ai S3 XRD
100.0
MS
Fe3O4+5
w .%
Ce2(CO3)3/500 ◦C/2
h/ai
S4 XRD
3.2
70.3
21.9
4.6
MS
9.8
66.3
21.0
1.5
Fe3O4+10
w .%
Ce2(CO3)3/500 ◦C/2
h/ai
S5 XRD
10.3
34.9
46.5
8.3
MS
14.9
45.4
36.5
2.7
Fe3O4+20
w .%
Ce2(CO3)3/500 ◦C/2
h/ai
S6 XRD
7.1
59.9
9.1
23.9
MS
10.2
66.3
19.6
2.1
Fe3O4+30
w .%
Ce2(CO3)3/500 ◦C/2
h/ai
S7 XRD
15.2
21.1
26.0
37.7
MS
13.8
41.1
40.2
3.0
Fe3O4+40
w .%
Ce2(CO3)3/500 ◦C/2
h/ai
S8 XRD
9.2
29.6
16.1
45.1
MS
11.1
55.6
28.3
2.0
Fe3O4+50
w .%
Ce2(CO3)3/500 ◦C/2
h/ai
S9 XRD
0.0
24.5
26.0
49.5
MS
12.7
51.5
30.8
2.8
Fig.
5
–
EDX
maps
o
cons i uen
elemen s
dis ibu ion
in
calcina ed
samples
wi h
nominal
composi ion
Fe3O4+10
w .%
Ce2(CO3)3(a)
and
Fe3O4+50
w .%
Ce2(CO3)3(b).

4436
j
m
a
e
e
s
e
c
h
n
o
l
.
2
0
2
0;9(3):4431–4439
Fig.
6
–
Pa icle
size
dis ibu ion
o
inpu
Fe-
and
Ce-oxides
(S1,
S3)
and
o
mixed
samples.
Fig.
7
–
Hys e esis
loops
o
he
ini ial
magne i e
(S1),
calcina ed
magne i e
(S2)
and
ce ium
ca bona e
(S3)
including
de ails
a
low
magne ic
fields.
o
S1,
S2,
and
mixed
S4
up
o
S9
samples
we e
e alua ed
wi h
a
se
o
Lo en zian
sex uple s
ep esen ed
e omagne ic
phases.
Besides
hem
also
he
double-line
componen s
we e
p esen
in
middle
o
all
samples
and
hey
a e
seen
also
in
spec a
p esen ed
in
Fig.
10.
Simila
spec a
a e
seen
and
discussed
in
Re .
[38].
In
case
o
he
S1
and
S2
samples
he
hype fine
pa ame e s,
ı
and
,
∼0.23
mm/s
and
0.35
mm/s,
o
Fig.
8
–
Dependence
o
magne ic
cha ac e is ics
on
olume
concen a ion
o
he
CeO2in
he
samples.
double-line
componen
can
be
asc ibed
o
Fe3+ ions.
In
he
mixed
samples
S4
up
o
S9
his
sub-componen
was
p esen
as
well
bu
ano he
pa amagne ic
componen
yielding
he
simila
hype fine
pa ame e
as
ob ained
o
ce ium
dioxide
in oduced
he eina e
was
de ec ed.
The
ep esen a ions
o
hese
componen s
we e
low
usually
a ound
1%.
The
spec um
o
ce ium
dioxide
(S3)
sample
was
fi ed
by
double-line
com-
ponen
wi h
he
isome
shi
ı
=
0.12
mm/s
and
quad upole
spli ing

=
0.58
mm/s
(86%)
and
single-line
componen
wi h
ı
=
0.25
mm/s
(14%)
which,
simila ly
as
in
p e ious
s udies
[30],
e iden ial
o
p esence
o
Fe-a oms.
The
e omagne ic
componen s
we e
i)
magne i e
ep e-
sen ed
by
alues
o
he
hype fine
induc ion
B
∼
48.6
T
and
∼
46.6
T,
o
he
isome
shi
ı∼
0.38
mm/s
and
∼
0.60
mm/s,
and
o
he
quad upole
spli ing

∼
−0.02
mm/s
and
∼
0.0
mm/s,
ii)
maghemi e
o
pa ame e s
B
∼
50.3
T,
ı
∼
0.27
mm/s,
and

∼
0.04
mm/s,
and
iii)
haema i e
B
∼
51.5
T,
ı
∼
0.37
mm/s,
and

∼
−0.18
mm/s.
These
Fe-oxide
phases
suppo
he
esul s
ob ained
abo e
by
XRD.
Ne e heless,
he
o he
componen
o
hype fine
pa ame e s
B
∼
41
T,
ı
∼
0.47
mm/s,
and

∼
−0.25
mm/s
was
de ec ed.
I
could
be
asc ibed
o
goe hi e.
The
ela i e
ep esen a ions
o
e omagne ic
phases
de ec ed
by
MS
a e
p esen
oge he
wi h
XRD
da a
in
Table
2.
The
j
m
a
e
e
s
e
c
h
n
o
l
.
2
0
2
0;9(3):4431–4439
4437
Fig.
9
–
Henkel
plo s
o
he
ini ial
(S1)
and
ea ed
(S2)
magne i e
and
he
mixed
Fe-oxide
wi h
a ious
con en
o
ce ium
dioxide
om
5
w .%
(S4)
up
o
50
w .%
(S9).
sligh
di e ences
in
alues
be ween
bo h
me hods
a e
due
o
highe
sensi i i y
o
Mössbaue
spec ome y
on
i on
con ain-
ing
phases
and
hei
o de ing.
3.3.
Deg ada ion
e ficiency
As
was
men ioned
abo e
a
sea ching
o
magne ically
sepa-
able
so ben s
is
in
p og ess
o
he
se e al
las
yea s.
He e,
he
deg ada ion
e ficiency
o
se
o
he
samples
wi h
a ying
ini ial
composi ions
o
magne i e/ce ium
ca bona e
and
cal-
cina ed
a
he
same
condi ions
was
es ed
o
he
deg ada ion
o
pa a hion
me hyl
(PM)
and
i s
con e sion
in o
4-ni o enol
(FN).
Du ing
his
chemical
p ocedu e
he
a e
o
chemical
eac-
ion
de e mines
he
dec easing
amoun
o
PM
and
inc easing
amoun
o
FN.
Bo h
componen s
can
be
measu ed
simul a-
neously.
This
eac ion
can
be
exp essed
by
simplified
ela ion
cPM =
cPM0 *
exp(−k* ),
whe e
k
is
a e
cons an
and
cPM0 is
he
ini ial
concen a ion
o
PM
compound
and
cPM is
concen a-
ion
o
PM
compound
a
ime
.
The
same
dependence
can
be
w i en
also
o
FN
componen .
The
changes
o
k
in
he
es ed
samples
a e
depic ed
in
Fig.
11.
I
seems
ha
cPM =
cFN is
alid
up
o
app oxima ely
25
ol.%
CeO2.
The
sligh
di e ences
obse ed
a
highe
CeO2con en s
can
imply
mo e
complica ed
eac ion.
I
appea s
also
ha
p esence
o
Fe-oxides
sligh ly
mode a e
he
a e
o
decomposi ion.
4.
Conclusions
P esen
in es iga ions
a e
de o ed
o
magne ically
sepa able
eac i e
so ben s
p epa ed
as
composi e
o
di e en
weigh
con en s
o
he
magne i e/ce ium
ca bona e
(100/0
up
o
50/50)
subjec ed
o
calcina ion
ea men s
a
500 ◦C
o
2
h
in
ai .
Fig.
10
–
Mössbaue
spec a
o
ini ial
(S1)
and
he mally
ea ed
(S2)
magne i e,
calcina ed
ce ium
ca bona e
(S3)
and
selec ed
mixed
samples
composed
o
Fe-oxide
and
o
30
w .%
(S7)
and
50
w .%
(S9)
ce ium
dioxide.
Va ious
cha ac e iza ion
expe imen al
me hods
ha e
e ealed
a
numbe
o
s uc u al
and
physical
aspec s.
The
main
conclusions
can
be
summa ised
subsequen ly.
•
Comme cial
magne i e
(Fe3O4)
con ains
also
small
amoun
o
maghemi e
and
␣-FeOOH
de ec ed
by
highly
sensi i e
Mössbaue
spec oscopy.
4438
j
m
a
e
e
s
e
c
h
n
o
l
.
2
0
2
0;9(3):4431–4439
Fig.
11
–
Deg ada ion
e ficiency
exp essed
as
he
a e
cons an
o
he
pa a hion
me hyl
decomposi ion
(PM,
•)
o
o
he
4-ni o enol
c ea ion
(FN,
o)
and
amoun
o
Fe-oxides
(夽)
in
dependence
o
CeO2con en
in
measu ed
samples.
•
Tempe a u e
ea men
(500 ◦C/2
h/ai )
o
magne i e
leads
o
he
ans o ma ion
in o
maghemi e
and
hema i e
and
dec eases
he
con en
o
␣-FeOOH.
•
All
hese
i on-oxides
a e
p esen
also
in
o he
samples
in
di e en
amoun s.
•
X- ay
di ac ion
o
ea ed
ce ium
ca bona e
(500 ◦C/2
h/ai )
confi ms
i s
ans o ma ion
in o
ce ium
oxide
o
he
fluo i e-like
c ys alline
s uc u e
and
flake- o m.
•
X- ay
di ac og am
analysis
yields
sligh ly
di e en
CeO2
con en
compa ed
o
nominal
one.
•
Di e ences
be ween
XRD
and
Mössbaue
esul s
in
ep-
esen a ion
o
indi idual
phases
a e
due
o
dissimila
sensi i i y
o
bo h
expe imen al
me hods.
•
Dispe sion
in
mic o-domain
and
pa icle
size
da a
despi e
he
same
ea ed
pa ame e s
o
all
samples
(500 ◦C/2
h/ai )
imply
ha
mo e
a en ion
should
be
done
o
condi ions
o
sample
p epa a ion
and
o
hei
subsequen
ea men .
•
Magne ic
cha ac e is ics,
sa u a ion
and
emanen
magne-
iza ions,
a e
de e mined
by
ype
and
con en
o
i on-oxide.
While
magne i e
(Ms
=
90÷100
Am2/kg)
and
maghemi e
(Ms
=
60÷80
Am2/kg)
a e
e imagne ic
wi h
only
sligh
di -
e ence
in
Ms
a
oom
empe a u e,
haema i e
is
weakly
e omagne ic
(Ms
∼
0.3
Am2/kg)
and
i s
highe
con en
in
he
samples
(S2,
S4,
S6,
S8,
S9)
con ibu es
o
he
lowe
alue
o
Ms.
Hype fine
induc ion
alues
(B)
a e
compa able
o
all
h ee
Fe-oxides
and
no
impo an
di e ences
among
sam-
ples
a e
he e o e
isible.
•
The
deg ada ion
e ficiency
seems
o
be
independen
on
ype
o
i on-oxide
bu
inc eases
wi h
con en
o
ce ium
dioxide.
•
Insu ficiency
o
p esen
s udies
is
ha
no
in o ma ion
con-
ce ning
ce ium
dioxide
was
ob ained
in
despi e
o
a ious
expe imen al
me hods.
Some
s udies
o
o he
au ho s
show
ha
ce ium
dioxide
can
con ain
besides
dominan
dia-
magne ic
Ce4+ ions
also
pa amagne ic
Ce3+ ions
mainly
a
pa icle
su aces
due
o
acancy- ype-de ec
o ma ion.
The
a io
o
Ce4+ and
Ce3+ ions
could
con ibu e
o
be e
expla-
na ion
o
he
deg ada ion
e ficiency.
Conflic s
o
in e es
The
au ho s
decla e
no
conflic s
o
in e es .
Acknowledgemen s
The
au ho s
hank
M.
Dosek
om
he
Facul y
o
En i onmen ,
Uni e si y
J.E.
Pu kyne
o
his
help
wi h
sample
p epa a-
ion.
This
wo k
was
unded
by
he
Czech
Science
Founda ion
ia
he
p ojec
No.
19-07460S
and
by
Minis y
o
Educa ion
You h
and
Spo s
o
he
Czech
Republic
ia
he
ollow-
ing
p ojec s:
No.
CZ.02.1.01/0.0/0.0/17
048/0007399
(ERDF/ESF
New
Composi e
Ma e ials
o
En i onmen al
Applica ions),
No.
LQ1601
(CEITEC
2020-Na ional
Sus ainabili y
P og amme
II),
ID
LM2015041
(CEITEC
Nano
Resea ch
In as uc u e),
No.
CZ.1.05/2.1.00/19.0387
(De elopmen
o
he
Resea ch
and
De elopmen
Base
o
RMSTC),
and
No.
2015073
(NanoEn iCz
Resea ch
In as uc u e).
Appendix
A.
Supplemen a y
da a
Supplemen a y
ma e ial
ela ed
o
his
a icle
can
be
ound,
in
he
online
e sion,
a
doi:h ps://doi.o g/10.1016/j.
jm .2020.02.068.
e
e
e
n
c
e
s
[1]
Renuka
NK,
P a een
AK,
Aniz
CU.
Ce ia
hombic
mic opla es:
syn hesis,
cha ac e iza ion
and
ca aly ic
ac i i y.
Mic opo ous
Mesopo ous
Ma e
2013;169:35–41,
h p://dx.doi.o g/10.1016/j.mic omeso.2012.10.010.
[2]
Kaneko
K,
Inoke
K,
F ei ag
B,
Hung ia
AB,
Midgley
PA,
Hansen
TW,
e
al.
S uc u al
and
mo phological
cha ac e iza ion
o
ce ium
oxide
nanoc ys als
p epa ed
by
hyd o he mal
syn hesis.
Nano
Le
2007;7:421–5,
h p://dx.doi.o g/10.1021/nl062677b.
[3]
Cab al
AC,
Ca alcan e
LS,
Deus
RC,
Longo
E,
Simoes
AZ,
Mou a
F.
Pho oluminescence
p ope ies
o
p aseodymium
doped
ce ium
oxide
nanoc ys als.
Ce am
In
2014;40:4445–53,
h p://dx.doi.o g/10.1016/j.ce amin .2013.08.117.
[4]
Dong
XT,
Mi
L,
Zhang
W,
Liu
GX,
Hong
GY.
P epa a ion
and
cha ac e iza ion
o
nanoc ys alline
CeO2
by
p ecipi a ion
me hod.
J
Ra e
Ea hs
2002;20:583–6.
[5]
Su esh
R,
Ponnuswamy
V,
Ma iappan
R.
E ec
o
annealing
empe a u e
on
he
mic os uc u al,
op ical
and
elec ical
p ope ies
o
CeO2
nanopa icles
by
chemical
p ecipi a ion
me hod.
Appl
Su
Sci
2013;273:457–64,
h p://dx.doi.o g/10.1016/j.apsusc.2013.02.062.
[6]
Li
M,
Liu
ZG,
Hu
YH,
Shi
ZX,
Li
HQ.
E ec s
o
he
syn hesis
me hods
on
he
physicochemical
p ope ies
o
ce ium
dioxide
powde .
Colloids
Su
A
Physicochem.
Eng.
Asp
2007;301:153–7,
h p://dx.doi.o g/10.1016/j.colsu a.2006.12.042.
[7]
Sun
CW,
Li
H,
Chen
LQ.
Nanos uc u ed
ce ia-based
ma e ials:
syn hesis,
p ope ies,
and
applica ions.
Ene gy
j
m
a
e
e
s
e
c
h
n
o
l
.
2
0
2
0;9(3):4431–4439
4439
En i on
Sci
2012;5:8475–505,
h p://dx.doi.o g/10.1039/c2ee22310d.
[8]
Mon ini
T,
Melchionna
M,
Monai
M,
Fo nasie o
P.
Fundamen als
and
ca aly ic
applica ions
o
CeO2-based
ma e ials.
Chem
Re
2016;116:5987–6041,
h p://dx.doi.o g/10.1021/acs.chem e .5b00603.
[9]
Pa k
SD,
Vohs
JM,
Go e
RJ.
Di ec
oxida ion
o
hyd oca bons
in
a
solid-oxide
uel
cell.
Na u e
2000;404:265–7.
[10]
Esposi o
V,
T a e sa
E.
Design
o
elec oce amics
o
solid
oxide
uel
cell
applica ions:
playing
wi h
ce ia.
J
Am
Ce am
Soc
2008;91:1037–51,
h p://dx.doi.o g/10.1111/j.1551-2916.2008.02347.x.
[11]
Jasinski
P,
Suzuki
T,
Ande son
HU.
Nanoc ys alline
undoped
ce ia
oxygen
senso .
Sens
Ac ua o s
B
Chem
2003;95:73–7,
h p://dx.doi.o g/10.1016/S0925-4005(03)00407-6.
[12]
A mini
S,
De
Messemaeke
J,
Whelan
CM,
Moinpou
M,
Maex
K.
Composi e
polyme
co e–ce ia
shell
ab asi e
pa icles
du ing
oxide
CMP:
a
de ec i i y
s udy.
J
Elec ochem
Soc
2008;155:H653–60,
h p://dx.doi.o g/10.1149/1.2949085.
[13]
Yabe
S,
Sa o
T.
Ce ium
oxide
o
sunsc een
cosme ics.
J
Solid
S a e
Chem
2003;171:7–11,
h p://dx.doi.o g/10.1016/S0022-4596(02)00139-1.
[14]
T u aul
L,
Ta
M-T,
De e s
T.
Applica ion
o
nanos uc u ed
Ca
doped
CeO2 o
ul a iole
fil a ion.
Ma e
Res
Bull
2010;45:527–35,
h p://dx.doi.o g/10.1016/j.ma e esbull.2010.02.008.
[15]
Janos
P,
Ku an
P,
Ko munda
M,
S engl
V,
G yga
TM,
Dosek
M,
e
al.
Ce ium
dioxide
as
a
new
eac i e
so ben
o
as
deg ada ion
o
pa a hion
me hyl
and
some
o he
o ganophospha es.
J
Ra e
Ea hs
2014;32:360–70,
h p://dx.doi.o g/10.1016/S1002-0721(14)60079-X.
[16]
Janos
P,
Hladik
T,
Ko munda
M,
Ede e
J,
S as ny
M.
The mal
ea men
o
ce ium
oxide
and
i s
p ope ies:
adso p ion
abili y
e sus
deg ada ion
e ficiency.
Ad
Ma e
Sci
Eng
2014;706041,
h p://dx.doi.o g/10.1155/2014/706041,
12
pages.
[17]
Ede e
J,
S as ny
M,
Dosek
M,
Henych
J,
Janos
P.
Mesopo ous
ce ium
oxide
o
as
deg ada ion
o
a yl
o ganophospha e
flame
e a dan
iphenyl
phospha e.
RSC
Ad
2019;9:32058–65,
h p://dx.doi.o g/10.1039/c9 a06575j.
[18]
Cela do
I,
Pede sen
JZ,
T a e sa
E,
Ghibelli
L.
Pha macological
po en ial
o
ce ium
oxide
nanopa icles.
Nanoscale
2011;3:1411–20,
h p://dx.doi.o g/10.1039/c0n 00875c.
[19]
Das
S,
Dowding
JM,
Klump
KE,
McGinnis
JF,
Sel
W,
Seal
S.
Ce ium
oxide
nanopa icles:
applica ions
and
p ospec s
in
nanomedicine.
Nanomedicine
UK
2013;8:1483–508,
h p://dx.doi.o g/10.2217/NNM.13.133.
[20]
Xu
C,
Qu
X.
Ce ium
oxide
nanopa icle:
a
ema kably
e sa ile
a e
ea h
nanoma e ial
o
biological
applica ions.
NPG
Asia
Ma e
2014;6:e90,
h p://dx.doi.o g/10.1038/am.2013.88.
[21]
Capu o
F,
De
Nicola
M,
Ghibelli
L.
Pha macological
po en ial
o
bioac i e
enginee ed
nanoma e ials.
Biochem
Pha macol
2014;92:112–30,
h p://dx.doi.o g/10.1016/j.bcp.2014.08.015.
[22]
Sunda esan
A,
Bha ga i
R,
Ranga ajan
N,
Siddesh
U,
Rao
CNR.
Fe omagne ism
as
a
uni e sal
ea u e
o
nanopa icles
o
he
o he wise
nonmagne ic
oxides.
Phys
Re
B
2006;74:161306,
h p://dx.doi.o g/10.1103/PhysRe B.74.161306.
[23]
Sunda esan
A,
Rao
CNR.
Fe omagne ism
as
a
uni e sal
ea u e
o
ino ganic
nanopa icles.
Nano
Today
2009;4:96–106,
h p://dx.doi.o g/10.1016/J.NANTOD.2008.10.002.
[24]
Ge
MY,
Wang
H,
Liu
EZ,
Liu
JF,
Jiang
JZ,
Li
YK,
e
al.
On
he
o igin
o
e omagne ism
in
CeO(2)
nanocubes.
Appl
Phys
Le
2008;93:062505,
h p://dx.doi.o g/10.1063/1.2972118.
[25]
Sha ma
SK,
Thaku
P,
Kuma
S,
Shukla
DK,
B ookes
NB,
Lee
CG,
e
al.
Room
empe a u e
e omagne ism
in
Fe-doped
CeO2 hin
films
g own
on
LaAlO3(001).
Thin
Solid
Films
2010;519:410–3,
h p://dx.doi.o g/10.1016/j. s .2010.08.096.
[26]
Thu be
A,
Reddy
KM,
Punnoose
A.
High- empe a u e
magne ic-field-induced
ac i a ion
o
oom- empe a u e
e omagne ism
in
Ce1-xNixO2.
J
Appl
Phys
2007;101:09N506,
h p://dx.doi.o g/10.1063/1.2709413.
[27]
Mis a
SK,
Ando enko
SI,
Engelha d
MH,
Thu be
A,
Reddy
KM,
Punnoose
A.
Role
o
dopan
inco po a ion
on
he
magne ic
p ope ies
o
Ce(1-x)Ni(x)O(2)
nanopa icles:
an
elec on
pa amagne ic
esonance
s udy.
J
Appl
Phys
2008;103:07D122,
h p://dx.doi.o g/10.1063/1.2833291.
[28]
Beausoleil
GL
II,
Thu be
A,
Rao
SS,
Alanko
G,
Hanna
CB,
Punnose
A.
Concen a ion
dependence
o
magne ic
momen
in
Ce1-xFexO2.
J
Appl
Phys
2012;111:07B546,
h p://dx.doi.o g/10.1063/1.3688933.
[29]
Lunacek
J,
Zi o sky
O,
Janos
P,
Dosek
M,
Ch obak
A,
Ma ysko
M,
e
al.
S uc u e
and
magne ic
p ope ies
o
syn hesized
fine
ce ium
dioxide
nanopa icles.
J
Alloys
Compd
2018;753:167–75,
h p://dx.doi.o g/10.1016/j.
jallcom.208.04.115.
[30]
Ji asko a
Y,
Bu sik
J,
Janos
P,
Lunacek
J,
Ch obak
A,
Zi o sky
O.
E ec
o
I on
impu i ies
on
magne ic
p ope ies
o
nanosized
CeO2and
Ce-based
compounds.
Me als
2019;9:222,
h p://dx.doi.o g/10.3390/me 9020222.
[31]
Lunacek
J,
Zi o sky
O,
Ji asko a
Y,
Bu sik
J,
Janos
P.
The mally
s imula ed
i on
oxide
ans o ma ions
and
magne ic
beha iou
o
ce ium
dioxide/i on
oxide
eac i e
so ben s.
Ma e
Cha ac
2016;120:295–303,
h p://dx.doi.o g/10.1016/j.ma cha .2016.09.009.
[32]
Kim
K,
Tsay
OG,
A wood
DA,
Chu chill
DG.
Des uc ion
and
de ec ion
o
chemical
wa a e
agen s.
Chem
Re
2011;111:5345–403,
h p://dx.doi.o g/10.1021/c 100193y.
[33]
In e na ional
union
o
c ys allog aphy;
book
se ies.Young
RA,
edi o .
The
Rie eld
me hod.
New
Yo k,
NY,
USA:
Ox o d
Uni e si y
P ess;
1993.
ISBN
0-19-855912-7.
[34]
ICSD
Da abase.
Ve sion
1.9.4;
NIST/FIZ,
ol.
1.
Ka ls uhe,
Ge many:
FIZ
Ka ls uhe;
2014.
[35]
Zak
T,
Ji asko a
Y.
CONFIT:
Mossbaue
spec a
fi ing
p og am.
Su
In e ace
Anal
2006;38:710–4,
h p://dx.doi.o g/10.1002/sia.2285.
[36]
Thamm
S,
Hesse
J.
A
simple
plo
indica ing
in e ac ions
be ween
single-domain
pa icles.
J
Magn
Magn
Ma e
1996;154:254–62,
h p://dx.doi.o g/10.1016/0304-8853(95)00585-4.
[37]
Co nell
RM,
Schwe mann
U.
The
I on
oxides:
s uc u e,
p ope ies,
eac ions,
occu ence
and
uses.
Weinheim:
VCH
Ve lagsgesellscha ;
1996.
p.
117.
[38]
Sahoo
SK,
Mohapa a
M,
Pandey
B,
Ve ma
HC,
Das
RP,
Anand
S.
P epa a ion
and
cha ac e iza ion
o
␣-Fe2O3-CeO2
composi e.
Ma e
Cha ac
2009;60:425–31,
h p://dx.doi.o g/10.1016/j.ma cha .2008.11.006.