FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS
The possibility of formation of an active interphase on iron particles in C/PVDF has been dictated by the thermochemical reactions of iron and iron oxides in the presence of carbon. The composition with polyvinylidene fluoride (PVDF) changed the redox activity of iron particles and decreased pure ir...
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V.I.Vernadsky Institute of General and Inorganic Chemistry
2023
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Репозитарії
Ukrainian Chemistry Journal| _version_ | 1871465914183974912 |
|---|---|
| author | Panteleimonov, Radyslav Pershina, Katherine Shcherbatiuk , Ivan |
| author_facet | Panteleimonov, Radyslav Pershina, Katherine Shcherbatiuk , Ivan |
| author_institution_txt_mv | [
{
"author": "Radyslav Panteleimonov",
"institution": "Vernadskii Institute of General and Inorganic Chemistry N.A.S of Ukraine, Kyiv, Palladin av., 32\/34, 03142 Ukraine"
},
{
"author": "Katherine Pershina",
"institution": "Vernadsky Institute of General and Inorganic Chemistry N.A.S of Ukraine, Kiev, Palladin av., 32\/34,03142 Ukraine"
},
{
"author": "Ivan Shcherbatiuk ",
"institution": "Joint Department of electrochemical Energy Systems, NAS of Ukraine"
}
] |
| author_sort | Panteleimonov, Radyslav |
| baseUrl_str | https://ucj.org.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-22T08:23:51Z |
| description | The possibility of formation of an active interphase on iron particles in C/PVDF has been dictated by the thermochemical reactions of iron and iron oxides in the presence of carbon. The composition with polyvinylidene fluoride (PVDF) changed the redox activity of iron particles and decreased pure iron (Fe0) amount by 0,24 wt. %. The surface properties of various compositions have been characterized by scanning electron microscopy with the analytical mode for determining the relationship between the microstructure and local thermal reactions on the iron particle surface. A relationship between the surface composition, morphology and electrochemical behavior of the Fe/C/PVDF electrodes has been found. Electric current affects the surface morphology and changes it from a mosaic structure to a monolith in atmosphere oxygen. The electrochemical properties of Fe/C/PVDF electrodes have been tested using cyclic voltammetry (CVA). The long air contact (for more than 3 hours) during electrochemical cycling changes the surface structure in the direction of decreasing crystallinity. The Fe/C/PVDF electrode can be charge in neutral solutions (pH ~7). |
| doi_str_mv | 10.33609/2708-129X.89.02.2023.91-99 |
| first_indexed | 2025-09-24T17:43:49Z |
| format | Article |
| fulltext |
91
UDC 621.351 doi: 10.33609/2708-129X.89.02.2023.91-99
FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES
IN C/PVDF ELECTROCHEMICAL SYSTEMS
Panteleimonov R.A.1, Shcherbatiuk I.M.2, Pershina K.D.1,2
1V.I.Vernadskyi Institute of General and Inorganic Chemistry, National Academy
of Sciences of Ukraine, Prospect Palladina, 32/34, 03142, Kyiv, Ukraine,
2Joint Department of Electrochemical Energy Systems, National Academy
of Sciences of Ukraine, Prospect Vernadskoho, 38, 03142, Kyiv, Ukraine
e-mail: radik20031@gmail.com
The possibility of formation of an active interphase on iron particles in C/PVDF has been
dictated by the thermochemical reactions of iron and iron oxides in the presence of carbon.
The composition with polyvinylidene fluoride (PVDF) changed the redox activity of iron par-
ticles and decreased pure iron (Fe0) amount by 0,24 wt. %. The surface properties of various
compositions have been characterized by scanning electron microscopy with the analytical
mode for determining the relationship between the microstructure and local thermal reac-
tions on the iron particle surface. A relationship between the surface composition, morpho
logy and electrochemical behavior of the Fe/C/PVDF electrodes has been found. Electric
current affects the surface morphology and changes it from a mosaic structure to a monolith
in atmosphere oxygen. The electrochemical properties of Fe/C/PVDF electrodes have been
tested using cyclic voltammetry (CVA). The long air contact (for more than 3 hours) during
electrochemical cycling changes the surface structure in the direction of decreasing crysta
llinity. The Fe/C/PVDF electrode can be charge in neutral solutions (pH ~7).
Key words: iron particle, active interphase, polyvinylidene fluoride, carbon, electrode.
INTRODUCTION. Using catalyst support
materials is essential to nanostructured ca
talytic systems in many energy-transforming
devices. Ideal catalyst carriers should possess
the following properties: high conductivity,
high surface area, low cost, electrochemical
inertness, and stability. Noble metals (Pt, Ru,
etc.) are considered to be the most active and
stable materials for green hydrogen (GH) pro-
duction but extremely high cost and limited
natural abundance impede their wide indus-
trial applications. Thus, nonplatinum active
metals such as Fe, Ni, or Co as well as their
alloys and composites have received great at-
tention as electrocatalysts for GH because of
their relatively low prices and availability [1].
Iron nanoparticle/polymer nanocomposites
have recently become some of the most active
research areas in the materials science and en-
gineering [1–3]. Among the nanosized fillers
92 ISSN 2708-129X. Укр. хім. журн., 2023
FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMSPHISICAL CHEMISTRY
for these composites, iron and its oxides (FeO,
Fe2O3, and Fe3O4) have attracted significant
interest owing to their ability for redox reac-
tions with huge heating effects and the ability
to form surface interphases, leading to diverse
applications in energy transforming devices
[4–7]. For the polymeric matrix, polyvi-
nylidene fluoride is a suitable semi-crystalline
polymer owing to its remarkable thermal sta-
bility, good chemical resistance, and extraordi-
nary pyroelectric and piezoelectric properties
[8]. These properties, combined with its high
elasticity, relative transparency, and ease of
processing, make this thermoplastic polymer
suitable for various technological applications.
PVDF shows a complex structure including five
distinct crystalline phases related to different
chain conformations designed, known as α,β,
δγ and ε phases [9,10]. Adding nanoparticles
to a matrix such as PVDF can enhance its con-
ductive performance and provide an advanced
response by changing the nature and proper-
ties of the nanoscale filler [11]. This matrix
forming an artificial interphase layer (a stable
fluorine-doped amorphous carbon (CF) layer)
for retaining uncontrollable metallic dendrites
and side reactions is a highly desirable stra
tegy for increasing coulombic efficiency and
limiting long cycling stability of metal batteries
[12]. Carbon-based materials have been used
as catalyst supports for a long time due to their
unique properties, such as physical stability,
excellent conductivity, and high surface area.
As the graphite anode in a lithium-ion battery,
hard carbon is a widely accepted anode materi-
al for different batteries and capacitors. Initial-
ly, the PVDF binder was used in the electro-
active hard-carbon anode. Nowadays, PVDF is
the main component of composite electrodes.
But this application of polyvinylidene fluoride
exhibits poor reversibility of electrodes. Some
authors attribute this impact to the formation
of fluoropolymer - a product of the polyme
rization of tetrafluoroethylene molecules [13].
CVA measurements and electrochemical im-
pedance spectroscopy data showed that im-
proved catalytic activity towards GH was the
result of an increase in the effective surface
area, a change in surface features upon heating
and the electrocatalytic synergism of Fe with
other components of composites [1]. That is
why the study of the appearance of new inter-
phases on the iron surface in composite Fe/C/
PVDF films and their impact on the electroca
talytic properties of composites are topical for
the development of a new generation of energy
storage for GH production.
EXPERIMENT AND DISCUSSION OF
THE RESULTS. Preparation of Fe/C/PVDF
electrode. A predetermined amount of iron
powder (PGR 3.200.28-30) with a bulk density
of 2.7 ± 0.2 g/cm3 (Ukraine) (Table 1), activa
ted carbon BAU-A (Ukraine), and 1 % solution
of PVDF in acetone (Sigma-Aldrich) stirred in
an ultrasonic mixer up to homogeneity. Before
mixing, powdered iron was treated with a solu-
tion of 1 M HNO3 to obtain oxides on the sur-
face of the iron particles. Then, the electrode
mass was pressed on a steel grid with a size of
1 cm2.
Table 1.
Mass fraction of impurities in powdered iron, wt. %
С Si Mn S P O
0.05± 0.01 0.08± 0.02 0.20± 0.01 0.02± 0.02 0.02± 0.02 0.5± 0.01
93https://ucj.org.ua
Panteleimonov R.A., Shcherbatiuk I.M., Pershina K.D. UCJ № 02/ Vol. 89
An electrochemical module Autolab 30
PGSTAT301N Metrohm Autolab with 3-elec-
trode cells was used for electrochemical stu
dies. Powdered iron was the working electrode,
the counter electrodes were platinum (Pt), car-
bon (C), and Ag/AgCl was reference electrode.
Cyclic voltammograms (CVA) and open cir-
cuit potential (OCP) data were recorded at a
potential scan rate of 0,1 and 50 mV/s in 0.1,
5 M solutions of NaOH and 1 M NaCl. Elec-
trochemical impedance spectra were recorded
in the potentiostatic mode both at open circuit
potentials and at overpotentials of 100, 200,
and 300 mV under H2 evolution in a frequency
range of 0.01 Hz ÷ 105 kHz with a constant ac
voltage amplitude of 10 mV. The data of elec-
trochemical impedance spectroscopy were pro-
cessed by FRA and Zview software packages.
The micromorphological studies of com-
posite samples and the quantitative microana
lysis of the surface were performed on a scan-
ning electron microscope Tescan Mira 3 LMU
on the cathode with Schottky field emission
and automatic measurement on images and on
an energy dispersive spectrometer Oxford In-
struments X-Max 80 mm2 SDD (table). The an-
alytical mode of the scanning microscope was
used to determine the relationship between the
microstructure and local thermal reactions on
iron particles.
The CVA of the Fe/C/PVDF electrode in
neutral and basic media has considerable diffe
rences in cathodic and anodic wave shapes and
they have different potential ranges of stability
(fig. 1 a, b). In the neutral media (NaCl), this
range is 0.5 – 0.75 V with surface passivation in
a wide potential range – 0.76 ÷ + 1.9 V vs NHE
(fig 1 a) with increasing internal area of CVA.
Fig 1. CVA curves of iron powder electrode:
a – in 1 M NaCl (neutral media), b – in 0,1 M NaOH (alkali media).
а
b
Fig 1. CVA curves of iron powder electrode: a – in 1 M NaCl (neutral media), b – in 0,1 M NaOH (alkali
media).
The increase in these areas during the cycling of the electrode indicates its capability to
charge. In the alkaline media, the potential range of stability increased up to 1.2–1.4 V without
any passivation (fig. 1 b, 2) explained by the formation of the hydroxides on the surface [6].
Logarithmic dependences of current changes have specified differences in the electrochemical
behavior of electrodes (Fig. 2).
a
а
b
Fig 1. CVA curves of iron powder electrode: a – in 1 M NaCl (neutral media), b – in 0,1 M NaOH (alkali
media).
The increase in these areas during the cycling of the electrode indicates its capability to
charge. In the alkaline media, the potential range of stability increased up to 1.2–1.4 V without
any passivation (fig. 1 b, 2) explained by the formation of the hydroxides on the surface [6].
Logarithmic dependences of current changes have specified differences in the electrochemical
behavior of electrodes (Fig. 2).
a
The increase in these areas during the cy-
cling of the electrode indicates its capability to
charge. In alkaline media, the potential range
of stability increased to 1.2 – 1.4 V without any
passivation (fig 1 b, 2), which is explained by
the formation of hydroxides on the surface [6].
Logarithmic dependences of current changes
have specific differences in the electrochemical
behavior of electrodes (Fig.2).
94 ISSN 2708-129X. Укр. хім. журн., 2023
FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMSPHISICAL CHEMISTRY
Fig. 2. Polarization curves of iron powder electrode in: a- 1 M NaCl; b - 0,1 M NaOH.
а
b
Fig 1. CVA curves of iron powder electrode: a – in 1 M NaCl (neutral media), b – in 0,1 M NaOH (alkali
media).
The increase in these areas during the cycling of the electrode indicates its capability to
charge. In the alkaline media, the potential range of stability increased up to 1.2–1.4 V without
any passivation (fig. 1 b, 2) explained by the formation of the hydroxides on the surface [6].
Logarithmic dependences of current changes have specified differences in the electrochemical
behavior of electrodes (Fig. 2).
a
b
Fig. 2. Polarization curves of iron powder electrode in: a- 1 M NaCl; b - 0,1 M NaOH.
According to the Tafel equations, the Fe/C/PVDF electrodes have only one zero net
current potential at the – 0.173 V, with further dissolution in a wide potential range from – 0.5 V
to – 2.29 V in neutral media (fig.2, a). In the alkaline electrolytes, the system has two zero net
potentials at the – 0.68 V and +0.35 V with a passivation range between -0.23 ÷ – 0.88 V (fig.
2,b) connecting with the impact of reversible redox reactions in the Fe/FexOy (x = 0 ÷ 3)
systems. Such behavior is connected with the active interphase generation on the electrode
surface based on the thermodynamics of the redox reactions (Table 2).
Table 2.
Standard enthalpies of redox reactions with oxygen and carbon for iron and its oxides [15].
Equation of reaction ΔН, kJ/M Equation of reaction ΔН, kJ/M
2Fe + 3/2O2→ FeO -824 FeO + C→ Fe + CO +100
2FeO+ 1/2 O2→ Fe3O4 -280 FeO + CО→ Fe + CO2 +17
Fe2O3+Fe= 3FeO +14,7 3Fe2O3 + CO =2Fe3O4+ CO2 +58
Fe2O3+Fe= 4FeO +16,8 Fe3O4 + CO = 3FeO + CO2 +38
Analysis of the Fe/C/PVDF electrode samples after 1 cycle found decreasing in the amount of
pure iron (Fe0) on 0.24 mas.% which would, probably, be connected with oxidizing of the iron in
reactions Fe2O3+Fe= 3FeO and Fe2O3+Fe= 4FeO under the current upload. The impact of
oxygen has a good correlation with surface morphology. Cycling under the limited presence of
oxygen brings the surface into a state of increasing of particle size with retention of the mosaic
surface structure (fig. 3 a). If the electrode surface has long contact with air, such a mosaic
structure became to monolayer structure (fig. 3 b).
According to the Tafel equations, the Fe/C/
PVDF electrodes have only one zero net cur-
rent potential at – 0.173 V with further disso-
lution in a wide potential range from – 0.5 V
to – 2.29 V in neutral media (fig.2, a). In al-
kaline electrolytes, the system has two zero
net potentials at – 0.68 V and +0.35 V with a
passivation range between – 0.23 and – 0.88 V
(fig.2,b) which is associated with the impact
of reversible redox reactions in Fe/FexOy (x =
0 ÷ 3)systems. This behavior is connected with
active interphase generation on the electrode
surface based on the thermodynamics of redox
reactions (Table 2).
95https://ucj.org.ua
Panteleimonov R.A., Shcherbatiuk I.M., Pershina K.D. UCJ № 02/ Vol. 89
Table 2.
Standard enthalpies of redox reactions with oxygen and carbon for iron and its oxides
[15].
Equation of reaction ΔН, kJ/M Equation of reaction ΔН, kJ/M
2Fe + 3/2O2→ FeO -824 FeO + C→ Fe + CO +100
2FeO+ 1/2 O2→ Fe3O4 -280 FeO + CО→ Fe + CO2 +17
Fe2O3+Fe= 3FeO +14,7 3Fe2O3 + CO =2Fe3O4+ CO2 +58
Fe2O3+Fe= 4FeO +16,8 Fe3O4 + CO = 3FeO + CO2 +38
An analysis of Fe/C/PVDF electrode sam-
ples after 1 cycle showed a decrease in the
amount of pure iron (Fe0) by 0.24 mas.% which
would, probably, be connected with the oxida-
tion of iron in the reactions Fe2O3+Fe= 3FeO
and Fe2O3+Fe= 4FeO under current load. The
impact of oxygen has a good correlation with
surface morphology. Cycling in the limited
presence of oxygen brings the surface into a
state of increasing particle size with retention
of the mosaic surface structure (fig.3 a). If the
electrode surface has long contact with air,
this a mosaic structure becomes a monolayer
structure (fig.3 b).
Fig. 3. SEM images of the surface of the electrode in the potential range – 0.23 ÷ -1.0 V: a – after
cycling in the limited presence of oxygen; b – after cycling in the prolonged contact with air.
a
b
Fig. 3. SEM images of the surface of the electrode in the potential range – 0.23 ÷ -1.0 V: a – after cycling
under the limited presence of oxygen; b – after cycling in the prolonged contact with air.
In this case, the transformation of surface morphology takes place. According to the
thermodynamic laws, the presence of an oxidized iron surface creates prerequisites for the
implementation of several thermochemical reactions. Oxidative reactions with oxygen are
exothermic, and reduction reactions of disproportionation and reactions with carbon and carbon
monoxide are endothermic (Table 3). Final calculations of the main molar enthalpies of iron
reactions in these systems: Σ ΔHex – Σ ΔHend = -1504 + 444.5 = 1059.5 (kJ/M) allows us to
assume that the presence of external temperature influence should lead to a shift in
thermodynamic equilibrium, i.e. can form local zones with the appropriate chemical potential.
Thus, the presence of carbon and powdered iron in the electrode composition creates
thermodynamic prerequisites for the appearance of temperature gradients on the electrode
surface in the absence of an electrical load. Enhancement of this effect is possible due to the
a
b
Fig. 3. SEM images of the surface of the electrode in the potential range – 0.23 ÷ -1.0 V: a – after cycling
under the limited presence of oxygen; b – after cycling in the prolonged contact with air.
In this case, the transformation of surface morphology takes place. According to the
thermodynamic laws, the presence of an oxidized iron surface creates prerequisites for the
implementation of several thermochemical reactions. Oxidative reactions with oxygen are
exothermic, and reduction reactions of disproportionation and reactions with carbon and carbon
monoxide are endothermic (Table 3). Final calculations of the main molar enthalpies of iron
reactions in these systems: Σ ΔHex – Σ ΔHend = -1504 + 444.5 = 1059.5 (kJ/M) allows us to
assume that the presence of external temperature influence should lead to a shift in
thermodynamic equilibrium, i.e. can form local zones with the appropriate chemical potential.
Thus, the presence of carbon and powdered iron in the electrode composition creates
thermodynamic prerequisites for the appearance of temperature gradients on the electrode
surface in the absence of an electrical load. Enhancement of this effect is possible due to the
In this case, a transformation of surface
morphology takes place. According to ther-
modynamic laws, the presence of an oxidized
iron surface creates prerequisites for the im-
plementation of several thermochemical re-
actions. Oxidation reactions with oxygen are
exothermic, and reduction disproportionation
reactions and reactions with carbon and car-
bon monoxide are endothermic (Table 3). Fi-
nal calculations of the main molar enthalpies
of iron reactions in these systems: Σ ΔHex–
Σ ΔHend= -1504 + 444.5 = 1059.5 (kJ/M)
96 ISSN 2708-129X. Укр. хім. журн., 2023
FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMSPHISICAL CHEMISTRY
allows us to assume that external temperature
influence should lead to a shift in thermody-
namic equilibrium, i.e. can form local zones
with the appropriate chemical potential. Thus,
the presence of carbon and powdered iron in
the electrode composition creates thermo-
dynamic prerequisites for the appearance of
temperature gradients on the electrode sur-
face in the absence of electrical load. The en-
hancement of this effect is possible due to the
introduction of impurities with low thermal
conductivity good thermal stability and tough-
ness. Polyvinylidene fluoride has all of these
properties. On the other hand, PVDF is a well-
known semicrystalline polymer in which the
percentage of the crystalline phase remarkably
affects almost all physical properties of poly-
mers. So, the change in surface morphology
can be the result of changes in PVDF crystal-
linity under temperature impact in the local
zones near iron particles. [14].
Further analysis of oxygen content detected a
difference in the oxygen content on the surface
of iron particles and in the bulk of graphite
(Fig.4, Table 3). This difference is related to the
ability of Fe coated by Fe3O4 in the presence
of graphite to induce the reduction of Fe3+ to
Fe2+ with the generation of free high reactive
oxygen. [16]. High by reactive oxygen is able to
form -O–O- and C=O groups on PVDF main-
ly due to the exchange of F in C-F groups [17].
According to these properties, PVDF could
have an initiator function to produce an active
oxygen species.
Fig.4. SEM image and analyzed zones on the surface of a Fe/C/PVDF film
introduction of impurities with low thermal conductivity with good thermal stability and
toughness. The polyvinylidene fluoride has all of these properties. On other hand, PVDF is a
well-known semicrystalline polymer in which the percentage of the crystalline phase remarkably
affects almost all physical properties of polymers. So, the changing of surface morphology can
be the result of changes in PVDF level crystallinity under temperature impact in the local zones
near iron particles. [14].
Further analysis of oxygen content detected the difference in the oxygen content on the
surface of iron particles and in the volume of graphite (Fig.4, Table 3). Such difference is related
to the ability of Fe coated by Fe3O4 in the presence of graphite to induce the reduction of Fe3+ to
Fe2+ with the generation of free high reactive oxygen. [16]. High reactive oxygen is able to form
-O–O- and C=O groups on PVDF mainly due to exchanging F in C–F groups [17]. According to
these properties, PVDF could have an initiator function to produce an active oxygen species.
Fig.4. SEM image and analyzed zones on the surface of Fe/C/PVDF film
Table 3.
The elementary composition of the composite film’s surface, wt.%
Zones of the
sample C O Fe F Ratio (formula)
Zone 1 23.21±2.1 48.83±0.3 26.23±0.5 0.77±0.5 FeC4O6
Zone 2 96.44±2.1 2.79±0.3 26.23±0.5 0.77±0.5 Fe3O C48
So, on the surface of iron particles forms a new interface (with size 30 ÷ 80 nm) (fig.4)
saturated by active oxygen compounds with high mobility. Confirmation of high mobility of
oxygen species is the analysis of graphite in the volume, where at a distance of more than 30 μm
the presence of oxygen is found, but in smaller quantities. Also, this region has detected Fe0. If
the presence of Fe2O3 takes place, the probability of the formation of Fe3C increases in the
graphite space. Thus, the simultaneous presence of proactive compounds of oxygen and iron
carbide should significantly affect the formation of gradient phenomena and change the
thermoelectric and electrochemical properties of the whole system.
CONCLUSIONS. The presence of an oxidized iron surface creates prerequisites for the
realization of several thermochemical reactions and induces the appearance of the local zones
with high temperatures. Under these temperatures, the probability of the iron ions reduction in
the presence of carbon and exchanging fluorine in C–F groups on oxygen with the formation of -
O–O- and C=O groups on PVDF is increasing. In this case, iron particles are becoming the
centers of formation of new active interphase with a high ability to redox transformation.
Temperature and changing chemical structure are the factors of changing level of crystallinity of
97https://ucj.org.ua
Panteleimonov R.A., Shcherbatiuk I.M., Pershina K.D. UCJ № 02/ Vol. 89
Table 3.
The elementary composition of the composite film surface, wt.%
Zones of the
sample C O Fe F Ratio (formula)
Zone 1 23.21±2.1 48.83±0.3 26.23±0.5 0.77±0.5 FeC4O6
Zone 2 96.44±2.1 2.79±0.3 26.23±0.5 0.77±0.5 Fe3O C48
So, on the surface of iron particles forms a
new interface (with a size of 30 ÷ 80 nm) (fig.4)
saturated by active oxygen compounds with
high mobility. A confirmation of the high mo-
bility of oxygen species is the analysis of gra
phite in the bulk, where at a distance of more
than 30 μm the presence of oxygen is found,
but in smaller quantities. Also, in this region
we detected Fe0. If the presence of Fe2O3 takes
place, the probability of the formation of Fe3C
increases in the graphite space. Thus, the si-
multaneous presence of proactive compounds
of oxygen and iron carbide should significant-
ly affect the formation of gradient phenomena
and change the thermoelectric and electro-
chemical properties of the whole system.
CONCLUSIONS. The presence of an oxi-
dized iron surface creates prerequisites for the
realization of several thermochemical reactions
and induces the appearance of the local zones
with high temperatures. At these temperatures,
the probability of the iron ions reduction in the
presence of carbon and exchanging fluorine in
C-F groups on oxygen with the formation of
-O–O- and C=O groups on PVDF increases.
In this case, iron particles become the centers
of formation of a new active interphase with
a high ability for redox transformation. Tem-
perature and changing chemical structure are
the factors of changing level of crystallinity of
PVDF, which affect the surface morphology
of Fe/C/PVDF electrodes. Under electric cur-
rent impact such composition is able to change
their electrochemical properties depending
on the pH of the electrolyte. In neutral solu-
tions (pH ~7), Fe/C/PVDF electrode has the
property of a capacitor and has battery redox
properties in alkaline solutions (pH~ 10).
AKNOLEDGEMENT. This work was
supported by the National Academy of
Sciences of Ukraine in the framework
of project 0122U200794.
УТВОРЕННЯ АКТИВНОЇ ІНТЕРФАЗИ НА
ЧАСТИНКАХ ЗАЛІЗА В ЕЛЕКТРОХІМІЧНИХ
СИСТЕМАХ C/PVDF
Р. А. Пантелеймонов1., І. М. Щербатюк2,
К. Д. Першина1,2
1Інститут загальної та неорганічної хімії
імені В. І. Вернадського НАН України,
проспект Академіка Палладіна, 32/34,
Київ 03142, Україна
2Міжвідомче відділення електрохімічної
енергетики НАН України,
проспект Академіка Вернадського, 38 А,
Київ 03142, Україна
e-mail: radik20031@gmail.com
98 ISSN 2708-129X. Укр. хім. журн., 2023
FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMSPHISICAL CHEMISTRY
Можливість утворення активної між-
фази на частинках заліза в середовищі
C/PVDF була продиктована термохіміч-
ними реакціями заліза та оксидів залі-
за за присутності вуглецю. Композиція з
полівініліденфторидом (PVDF) змінила
окисно-відновну активність частинок за-
ліза та зменшила кількість чистого заліза
(Fe0) на 0,24 мас. %. Властивості поверхні
різних композицій було охарактеризовано
за допомогою скануючої електронної мі-
кроскопії з аналітичним режимом для ви-
значення зв'язку між мікроструктурою та
локальними тепловими реакціями на по-
верхні частинки заліза. Було знайдено зв’я-
зок між складом поверхні, морфологією та
електрохімічною поведінкою електродів
Fe/C/PVDF. Електричний струм впливає на
морфологію поверхні та змінює її з моза-
їчної структури на моноліт за присутності
кисню повітря. Тривалий контакт повітря
(понад 3 години) під час електрохімічно-
го циклування змінює структуру поверхні
в бік зниження кристалічності. Електрод
Fe/C/PVDF може заряджатися в нейтраль-
них розчинах (pH ~7).
Ключові слова: частинка заліза, актив-
на міжфаза, полівініліденфторид, вуглець,
електрод.
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Стаття надійшла 05. 02. 2023.
|
| id | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-532 |
| institution | Ukrainian Chemistry Journal |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-23T01:09:36Z |
| publishDate | 2023 |
| publisher | V.I.Vernadsky Institute of General and Inorganic Chemistry |
| record_format | ojs |
| resource_txt_mv | ucjorgua/07/79dfadc017a4a2b1ebbdf17dc7758b07.pdf |
| spelling | oai:ojs2.1444248.nisspano.web.hosting-test.net:article-5322026-07-22T08:23:51Z FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS Panteleimonov, Radyslav Pershina, Katherine Shcherbatiuk , Ivan iron particle, active interphase, polyvinylidene fluoride, carbon, electrode. The possibility of formation of an active interphase on iron particles in C/PVDF has been dictated by the thermochemical reactions of iron and iron oxides in the presence of carbon. The composition with polyvinylidene fluoride (PVDF) changed the redox activity of iron particles and decreased pure iron (Fe0) amount by 0,24 wt. %. The surface properties of various compositions have been characterized by scanning electron microscopy with the analytical mode for determining the relationship between the microstructure and local thermal reactions on the iron particle surface. A relationship between the surface composition, morphology and electrochemical behavior of the Fe/C/PVDF electrodes has been found. Electric current affects the surface morphology and changes it from a mosaic structure to a monolith in atmosphere oxygen. The electrochemical properties of Fe/C/PVDF electrodes have been tested using cyclic voltammetry (CVA). The long air contact (for more than 3 hours) during electrochemical cycling changes the surface structure in the direction of decreasing crystallinity. The Fe/C/PVDF electrode can be charge in neutral solutions (pH ~7). V.I.Vernadsky Institute of General and Inorganic Chemistry 2023-03-24 Article Article Physical chemistry Физическая xимия Фізична xімія application/pdf https://ucj.org.ua/index.php/journal/article/view/532 10.33609/2708-129X.89.02.2023.91-99 Ukrainian Chemistry Journal; Vol. 89 No. 2 (2023): Ukrainian Chemistry Journal; 91-99 Украинский химический журнал; ##issue.vol## 89 ##issue.no## 2 (2023): Ukrainian Chemistry Journal; 91-99 Український хімічний журнал; Том 89 № 2 (2023): Український хімічний журнал; 91-99 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/532/268 Copyright (c) 2023 Radyslav Panteleimonov, Katherine Pershina, Ivan Shcherbatiuk https://creativecommons.org/licenses/by-nc/4.0 |
| spellingShingle | Panteleimonov, Radyslav Pershina, Katherine Shcherbatiuk , Ivan FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS |
| title | FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS |
| title_full | FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS |
| title_fullStr | FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS |
| title_full_unstemmed | FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS |
| title_short | FORMATION OF ACTIVE INTERPHASE ON THE IRON PARTICLES IN C/PVDF ELECTROCHEMICAL SYSTEMS |
| title_sort | formation of active interphase on the iron particles in c/pvdf electrochemical systems |
| topic_facet | iron particle active interphase polyvinylidene fluoride carbon electrode. |
| url | https://ucj.org.ua/index.php/journal/article/view/532 |
| work_keys_str_mv | AT panteleimonovradyslav formationofactiveinterphaseontheironparticlesincpvdfelectrochemicalsystems AT pershinakatherine formationofactiveinterphaseontheironparticlesincpvdfelectrochemicalsystems AT shcherbatiukivan formationofactiveinterphaseontheironparticlesincpvdfelectrochemicalsystems |