Optimal conditions were found for the formation of carbon-oxide composites by the treatment of mixtures
of oxides of aluminum or titanium with carbon nanotubes and nanofibers in a planetary ball mill.
The dependences of the electrical conductivity of composites on the content of carbon nanomaterials (1-5%
by mass) were determined. It is shown that the addition of 3%(wt) of CNT to the oxides leads to a sharp increase
in the electrical conductivity: from 5.0×10-8 to 2.8×10-4 S/cm for Al2O3 and from 5.0×10-6 to 2.2×10-2
S/cm for TiO2. It was shown that the carbon-oxide composites are promising carriers of the catalysts of
electrode processes in electrochemical devices. It was revealed that Pt/TiO2 - CNT catalyst containing 5%
(mass) of carbon nanotubes has the best catalytic activity in oxygen reduction, in an electrode-modeling
cathode of a fuel cell.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3512

Belmesov, A.A.

Gerasimova, E.V.

Shchur, D.V.

Tarasov, B.P.

Volodin, A.A.

Zolotarenko, A.D.

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 1 No 3, 03CNN19(4pp) (2012)   2304-1862/2012/1(3)03CNN19(4) 03CNN19-1  2012 Sumy State University Electro-Conductive Composites Based on Metal Oxides and Carbon Nanostructures  A.A. Volodin1,*, A.A. Belmesov1, E.V. Gerasimova1, A.D. Zolotarenko2, D.V. Shchur2, B.P. Tarasov1,†  1 Institute of Problems of Chemical Physics of RAS, 1, Prosp. Akademika Semenova, 142432 Chernogolovka, Russia 2 Frantsevich Institute for Problems of Materials Science of NASU, 3, Krzhizhanovsky str., 03680 Kyiv-142, Ukraine  (Received 24 June 2012; published online 14 August 2012)  Optimal conditions were found for the formation of carbon-oxide composites by the treatment of mix-tures of oxides of aluminum or titanium with carbon nanotubes and nanofibers in a planetary ball mill. The dependences of the electrical conductivity of composites on the content of carbon nanomaterials (1-5% by mass) were determined. It is shown that the addition of 3%(wt) of CNT to the oxides leads to a sharp in-crease in the electrical conductivity: from 5.0×10-8 to 2.8×10-4 S/cm for Al2O3 and from 5.0×10-6 to 2.2×10-2 S/cm for TiO2. It was shown that the carbon-oxide composites are promising carriers of the catalysts of electrode processes in electrochemical devices. It was revealed that Pt/TiO2 - CNT catalyst containing 5% (mass) of carbon nanotubes has the best catalytic activity in oxygen reduction, in an electrode-modeling cathode of a fuel cell.  Keywords: Carbon nanotubes, Carbon-ceramic nanocomposites, Electrical conductivity, Catalytic activity.    PACS numbers: 61.48.De, 81.05.Mh, 72.80.Tm                                                             * alexvol@icp.ac.ru † tarasov@icp.ac.ru 1. INTRODUCTION  Composites based on ceramics and carbon materials have wide prospects for the modern industry [1-5]. Of certain interest is to use carbon nanotubes as modify-ing components. Thus the high thermal conductivity of nanotubes suggests that their introduction to the ce-ramic material, even in small amounts, would improve thermal conductivity and resistance to thermal shock [2]. The electrical conductivity of such composites can be useful for creating various electrochemical devices [3]. Thus, to give conductive properties through the introduction of small additions of carbon nanomaterials is attractive compared to other composite systems. In the production of electrically conductive composites with the dielectric matrix and conductive filler there are of particular importance the intrinsic conductivity of the filler particles, the amount of injected filler, as well as the shape of the filler particles. Currently, a huge number of composites based on Al2O3 [4-8], Si3N4 [8, 9], SiC [10], SiO2 [11], TiO2 [12-14], ZnO [14, 15], TiN [16], ZrO2 [17] etc. are investigated. At the same time one use carbon black, nanofibers, multiwall and single-wall nanotubes, and graphene structures as fillers [4-20]. To create high-performance composite materials is necessary to introduce additives, which will either im-prove the properties of the base material, or give it new ones, but it is important to maintain existing properties. Therefore, to achieve the best effect it is necessary to introduce a minimum amount of additives, which give new properties to composites. In the literature data studied by us the content of carbon materials in the composites ranged from one percent to several tens of percent. In this connection, one of the problems is the determination of the minimum content of carbon in the composite material that provides the desired properties. The aim of this work is to obtain conductive carbon-oxide composites based on Al2O3 and TiO2, and study the dependence of the specific conductivity of compo-sites on the conditions of their formation and types of carbon nanostructures (CNS). 2. EXPERIMENTAL  We used powders of TiO2 (anatase and rutile mix-ture), and γ-Al2O3. In order to form composites carbon nanofibers were obtained with diameters of 100 – 200 nm, multiwalled nanotubes with diameters of 10 – 50 nm, as well as thin tubes with diameters of 5 – 10 nm. Carbon-ceramic composites were prepared by mixing carbon nanostructures with metal oxides in a planetary ball mill. Such parameters as rotation speed, milling time, type and mass content of the CNS were varied. The structure and phase composition of the samples were investigated by transmission electron microscopy on instruments EMW–100B and JEOL JEM–100 CX. In order to study the surface of the composites we used a field emission scanning electron microscope Zeiss LEO SUPRA 25, equipped with EDX attachment for X-ray microanalysis of the elemental composition of the sample surface. X-ray analysis of the samples was car-ried out on a powder diffractometer DRON–UM2. Thermogravimetric analysis of the samples was per-formed on the instrument STA 409C LUXX. To meas-ure the specific surface area an analyzer QUAD-RASORB SI was used. Electrical conductivity of the materials was determined on a potentiostat P–30S (Elins Co). We used four- and double- zoned cells with electrodes 0.5 and 0.3 cm in diameter. In addition, to the surface of the obtained composite materials platinum clusters were deposited and their electrocatalytic activity in oxygen reduction was inves-tigated. Tests were conducted with the cathode elec-trode of fuel cell modeling. Cyclic volt-ammograms rec-orded at various speeds with the potential sweep blow-ing air through gas-conducting channels. After regis-tration, the cyclic volt-ammograms stationary currents in potentiostatic mode were recorded. For this we used potentiostat P–30S and impedancemeter Z–500PX (Elins Co).    A.A. VOLODIN, A.A. BELMESOV, E.V. GERASIMOVA, ET AL. PROC. NAP 1, 03CNN19 (2012)   03CNN19-2 3. RESULTS AND DISCUSSION  To investigate the dependence of conductivity on the content of carbon nanomaterial mixtures contain-ing from 1 to 5%(wt) of CNTs were prepared. After pro-cessing in a planetary ball mill the samples of oxide powders and nanotubes had a homogeneous appear-ance, however, at the study by electron microscopy in mixtures containing 1% and 2%(wt) CNTs, the tubes on their own are almost not observed. At the content of 3%(wt) as bundles of nanotubes, as well as individual tubes could be observed. At the content of 5%(wt) a large number of nanotube bundles, distributed between the oxide particles were observed. This pattern was observed in the case of aluminum oxide, as well as in the case of titanium oxide (Fig. 1).    Fig. 1 – TEM image of the composite MCNT/Al2O3, with 5%(wt) of MCNT  We selected optimal conditions for processing time, the degree of load, type and content of the carbon na-nomaterial. Investigation of the electrical conductivity of composites based on Al2O3 with different content of carbon nanotubes have shown that the dependence is exponential. At the content of CNT 1 – 2%(wt) the elec-trical conductivity remains practically unchanged and amounts to about 5×10-8 S/cm. The increase of the nanotubes content up to 5%(wt) leads to a sharp in-crease in conductivity up to 3×10-4 S/cm. In this case one can observe a jump of conductivity at 3%(wt) to 4.5×10-5 S/cm. In the case of TiO2 this effect also occurs at 3%(wt) of CNTs and the electrical conductivity of this composite is 2.2×10-3 S/cm. In general, the conduc-tivity varies from 5×10-6 S/cm for pure TiO2 up to 2.2×10-2 S/cm for the composite containing 5%(wt) of CNTs (Fig. 2). For selection of the optimum degree of load and milling time in the future we used a composite with 3%(wt) of carbon nanostructures. The experiments re-vealed that the highest conductivity of milled compo-sites reached at 100 rpm, for 30 min (Fig. 3, 4). A fur-ther increase in time or number of revolutions leads to a refinement of carbon nanostructures and, conse-quently, reduces the conductivity. At the study of the electrical conductivity of compo-sites according to the type of carbon nanostructures, it was found that the composites with multiwall carbon nanotubes have the best conductivity (Fig. 5), the conduc-tivity of composites with single-walled carbon nanotubes (SWNT) is worse by two orders of magnitude; a composite with carbon nanofibers (CNF) has the worst conductivity. 0 1 2 3 4 510-910-810-710-610-510-410-310-2  MWNT/TiO2 MWNT/Al2O3Specific Conductivity (S/cm)Content MWNT (%wt)   Fig. 2 – Dependence of the conductivity of the composites MCNT/Al2O3 and MCNT/TiO2 on the mass content of carbon nanotubes  100 200 300 400 50010-810-710-610-510-410-3Specific Conductivity (S/cm)Rotational Speed (rpm)   Fig. 3 – Dependence of the conductivity of the composites TiO2/MCNT (3%wt) on the number of revolutions  15 30 45 6010-610-510-410-3Specific Conductivity (S/cm)Time (min)   Fig. 4 – Dependence of the conductivity of the composites TiO2/MCNT (3%wt) on the milling time  For a detailed description of the formation condi-tions of carbon-oxide composites in a planetary ball mill the magnitude of strain effect on the material was also determined during the machining method of the test sites and the energy transferred to the sample dur- ELECTRO-CONDUCTIVE COMPOSITES BASED ON METAL OXIDES … PROC. NAP 1, 03CNN19 (2012)   03CNN19-3 ing ball-milling was calculated [21]. This method uses a universal value that allows one to be independent on the type of mill and sufficiently facilitates the produc-tion and optimization of the processes of formation of composite materials in conditions of a variety of grind-ing and mixing machines.  10-610-510-410-310-2 SWNT/TiO2MWNT/TiO2Specific Conductivity (S/cm)CNF/TiO2   Fig. 5 – Dependence of the conductivity of the composites CNS/TiO2 (3%wt) on the type of carbon nanostructures con-tained in it  According to the results of calculations of the dose of strain effect and the data of the electrical conductivi-ty of composites plots of the dependence of electrical conductivity of composites MWNT/TiO2 on the dose of strain effect on the samples were constructed (Fig. 6).  30 100 1000 1000010-710-610-510-410-3Specific Conductivity (S/cm)Dose of Strain Effects (J/g)   Fig. 6 – Dependence of the conductivity of the composite MWNT/TiO2 on the dose of strain effect on the samples  As can be seen from the figure, the samples ob-tained by mechanical action 76 J/g have the highest conductivity (4.5×10-3 S/cm). Further increase of the load and processing time leads to a decrease in electri-cal conductivity, which is obviously due to the oxide shredding and destruction of carbon nanotubes. This assumption is confirmed by the values of specific sur-face area of the composites, which vary from 55 m2/g for the composites obtained at a dose of strain effect 38 J/g to 80 m2/g for the composites obtained at 9.6 kJ/g. A similar pattern is observed in the case of composites based on aluminum oxide.  To evaluate the effectiveness of the use of CNT/TiO2 composite as a carrier of catalysts in electrochemical devices Pt/TiO2-CNT samples with different contents of carbon nanotubes were prepared and their electrocata-lytic activity was investigated using an electrode-modeling cathode of a fuel cell. According to scanning electron microscopy Pt particles are distributed over the surface of titanium oxide fairly evenly. The average particle size is in the range 5-10 nm (Fig. 7). According to the EDX Pt content is at a level of 10%(wt).    Fig. 7 – SEM image of TiO2 with Pt clusters deposited on it  Current-voltage characteristics of the system Pt/TiO2 – CNT with different mass content of carbon nanotubes are shown on Figure 8.  0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.200100200300400500600700800900 Pt/TiO2+MWNT(50%) Pt/TiO2+MWNT(15%) Pt/TiO2+MWNT(3%) Pt/TiO2+MWNT(5%)Potential (mV)Current Density (A/cm2)   Fig. 7 – SEM image of TiO2 with Pt clusters deposited on it  The composite with 5%(wt) of MWNT is the most ef-fective. The composite with 3%(wt) content of CNT has lower quantity of extended carbon structures providing electron transport, and in samples with 15 and 50%(wt) of CNT the low efficiency of Pt-catalyst may be related to difficulties of contact with the reaction medium be-cause of the large amount of carbon material. According to literature data, at the presence of spherical particles of the conducting phase and parti-cles of non-conductive matrix of the same size for the occurrence of the percolation the content of the con-ducting phase should be at the level of 50%. In the case of ellipsoidal particles this content reduces to 20-30%. For filamentous particles, this value is usually less  A.A. VOLODIN, A.A. BELMESOV, E.V. GERASIMOVA, ET AL. PROC. NAP 1, 03CNN19 (2012)   03CNN19-4 than 10%. In the case of composites obtained by the synthesis of carbon nanostructures directly on the sur-face of oxide powders, apparently, there is a tight con-tact both between the carbon tubes and between tubes and particles of oxides.  CONCLUSIONS  Optimal conditions were determined for the for-mation of carbon-oxide composites by the treatment of mixtures of oxides of a metal with carbon nanomateri-als in a planetary ball mill. The dependences of the electrical conductivity of composites on the content of carbon nanomaterials (1–5%wt) were determined. It is established that the addition of 3%(wt) of CNT to the oxides leads to a sharp increase in the electrical con-ductivity: from 5.0×10-8 to 2.8×10-4 S/cm for Al2O3 and from 5.0×10-6 to 2.2×10-2 S/cm for TiO2. It was shown that the carbon-oxide composites are promising carri-ers of the catalysts of electrode processes in electro-chemical devices. It was revealed that Pt/TiO2 – CNT catalyst containing 5%(wt) of carbon nanotubes has the best catalytic activity in oxygen reduction, in an elec-trode-modeling cathode of a fuel cell.  AKNOWLEDGEMENTS  The work was supported by RFBR (Project № 11-03-90454 Ukr_f_a) and by the Program OChNM-02.  REFERENCES  1. Composites: ASM Handbook (Ed. D.B. Miracle, S.L. Don-aldson) (ASM International: The Materials Information Company: 2001). 2. J.A. Arsecularatne, L.C. Zhang, Recent Patents on Nano-tech. 1, 176 (2007). 3. D. Eder, Chem. Rev. 110, 1348 (2010). 4. Y.V. Blagoveschensky, K.V. Van, A.A. Volodin, V.M. Kiiko, A.A. Kolchin, N.I. Novokhatskaya, B.P. Tarasov, A.N. Tolstun, Composites and Nanostructures 1, 30 (2010). 5. B.P. Tarasov, V.E. Muradyan, A.A. Volodin, Russ. Chem. Bull. 60, 1261 (2011). 6. Yu. Fan, L. Wang Carbon 48, 1743 (2010). 7. A.M. Bondar, I. Iordache, J. Optoelectronics and Adv. Ma-ter. 8, 631 (2006). 8. F-H.Su, Zh-Zh.Zhang, K.Wang, Composites: Part A 37, 1351 (2006). 9. B. Fényi, N. Hegman, F. Wéber, Processing and Applica-tion of Ceram. 1–2, 57 (2007). 10. G-B. Zheng, H. Sano, Y. Uchiyama, Composites: Part B 42, 2158 (2011). 11. S.Q. Guo, R. Sivakumar, H. Kitazawa, Y.Kagawa, J. Am. Ceram. Soc. 90, 1667 (2007). 12. J. Yu, J. Fan, B. Cheng, J. Power Sources 196, 7891 (2011). 13. O.Yu. Ivanshina, M.E. Tamm, E.V. Gerasimova, Inorg. Mater. 47, 618 (2011). 14. C. Martínez, M. Canle, M.I. Fernándeza, Appl. Catal. B: Environmental 102, 563 (2011). 15. X.L. Li, C. Li, Y. Zhang, Nanoscale Res. Lett. 5, 1836 (2010). 16. L.Q. Jiang, L.Gao, J. Mater. Chem. 15, 260 (2005). 17. S.L. Shi, J. Liang, J. Appl. Phys. 101, 023708 (2007). 18. Zh-Sh. Wu, G. Zhou, Li-Ch. Yina, Nano Energy 1, 107 (2012). 19. B.P. Tarasov, V.E. Muradyan, A.A. Volodin, Fullerenes and Nanostructures in Condensed Matter (Minsk: Publish-ing Center BSU: 2011). 20. A.A. Volodin, D.V. Chihirev, A.D. Zolotarenko, D.V. Schur, B.P. Tarasov, Fullerenes and Nanostructures in Condensed Matter (Minsk: Publishing Center BSU: 2011). 21. P.Yu. Butyagin, A.N. Streletskii, Phys. Solid State 47, 856 (2005). 

Electro-Conductive Composites Based on Metal Oxides and Carbon Nanostructures

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 1 No 3, 03CNN19(4pp) (2012) 
 
 
2304-1862/2012/1(3)03CNN19(4) 03CNN19-1  2012 Sumy State University 
Electro-Conductive Composites Based on Metal Oxides and Carbon Nanostructures 
 
A.A. Volodin1,*, A.A. Belmesov1, E.V. Gerasimova1, A.D. Zolotarenko2, D.V. Shchur2, B.P. Tarasov1,† 
 
1 Institute of Problems of Chemical Physics of RAS, 1, Prosp. Akademika Semenova, 142432 Chernogolovka, Russia 
2 Frantsevich Institute for Problems of Materials Science of NASU, 3, Krzhizhanovsky str., 03680 Kyiv-142, Ukraine 
 
(Received 24 June 2012; published online 14 August 2012) 
 
Optimal conditions were found for the formation of carbon-oxide composites by the treatment of mix-
tures of oxides of aluminum or titanium with carbon nanotubes and nanofibers in a planetary ball mill. 
The dependences of the electrical conductivity of composites on the content of carbon nanomaterials (1-5% 
by mass) were determined. It is shown that the addition of 3%(wt) of CNT to the oxides leads to a sharp in-
crease in the electrical conductivity: from 5.0×10-8 to 2.8×10-4 S/cm for Al2O3 and from 5.0×10-6 to 2.2×10-2 
S/cm for TiO2. It was shown that the carbon-oxide composites are promising carriers of the catalysts of 
electrode processes in electrochemical devices. It was revealed that Pt/TiO2 - CNT catalyst containing 5% 
(mass) of carbon nanotubes has the best catalytic activity in oxygen reduction, in an electrode-modeling 
cathode of a fuel cell. 
 
Keywords: Carbon nanotubes, Carbon-ceramic nanocomposites, Electrical conductivity, Catalytic activity. 
 
  PACS numbers: 61.48.De, 81.05.Mh, 72.80.Tm 
 
 
                                                          
* alexvol@icp.ac.ru 
† tarasov@icp.ac.ru 
1. INTRODUCTION 
 
Composites based on ceramics and carbon materials 
have wide prospects for the modern industry [1-5]. Of 
certain interest is to use carbon nanotubes as modify-
ing components. Thus the high thermal conductivity of 
nanotubes suggests that their introduction to the ce-
ramic material, even in small amounts, would improve 
thermal conductivity and resistance to thermal shock 
[2]. The electrical conductivity of such composites can 
be useful for creating various electrochemical devices 
[3]. Thus, to give conductive properties through the 
introduction of small additions of carbon nanomaterials 
is attractive compared to other composite systems. 
In the production of electrically conductive composites 
with the dielectric matrix and conductive filler there are 
of particular importance the intrinsic conductivity of the 
filler particles, the amount of injected filler, as well as the 
shape of the filler particles. Currently, a huge number of 
composites based on Al2O3 [4-8], Si3N4 [8, 9], SiC [10], 
SiO2 [11], TiO2 [12-14], ZnO [14, 15], TiN [16], ZrO2 [17] 
etc. are investigated. At the same time one use carbon 
black, nanofibers, multiwall and single-wall nanotubes, 
and graphene structures as fillers [4-20]. 
To create high-performance composite materials is 
necessary to introduce additives, which will either im-
prove the properties of the base material, or give it new 
ones, but it is important to maintain existing properties. 
Therefore, to achieve the best effect it is necessary to 
introduce a minimum amount of additives, which give 
new properties to composites. In the literature data 
studied by us the content of carbon materials in the 
composites ranged from one percent to several tens of 
percent. In this connection, one of the problems is the 
determination of the minimum content of carbon in the 
composite material that provides the desired properties. 
The aim of this work is to obtain conductive carbon-
oxide composites based on Al2O3 and TiO2, and study 
the dependence of the specific conductivity of compo-
sites on the conditions of their formation and types of 
carbon nanostructures (CNS). 
2. EXPERIMENTAL 
 
We used powders of TiO2 (anatase and rutile mix-
ture), and γ-Al2O3. In order to form composites carbon 
nanofibers were obtained with diameters of 100 – 200 
nm, multiwalled nanotubes with diameters of 10 – 50 
nm, as well as thin tubes with diameters of 5 – 10 nm. 
Carbon-ceramic composites were prepared by mixing 
carbon nanostructures with metal oxides in a planetary 
ball mill. Such parameters as rotation speed, milling 
time, type and mass content of the CNS were varied. 
The structure and phase composition of the samples 
were investigated by transmission electron microscopy 
on instruments EMW–100B and JEOL JEM–100 CX. 
In order to study the surface of the composites we used 
a field emission scanning electron microscope Zeiss 
LEO SUPRA 25, equipped with EDX attachment for 
X-ray microanalysis of the elemental composition of the 
sample surface. X-ray analysis of the samples was car-
ried out on a powder diffractometer DRON–UM2. 
Thermogravimetric analysis of the samples was per-
formed on the instrument STA 409C LUXX. To meas-
ure the specific surface area an analyzer QUAD-
RASORB SI was used. Electrical conductivity of the 
materials was determined on a potentiostat P–30S 
(Elins Co). We used four- and double- zoned cells with 
electrodes 0.5 and 0.3 cm in diameter. 
In addition, to the surface of the obtained composite 
materials platinum clusters were deposited and their 
electrocatalytic activity in oxygen reduction was inves-
tigated. Tests were conducted with the cathode elec-
trode of fuel cell modeling. Cyclic volt-ammograms rec-
orded at various speeds with the potential sweep blow-
ing air through gas-conducting channels. After regis-
tration, the cyclic volt-ammograms stationary currents 
in potentiostatic mode were recorded. For this we used 
potentiostat P–30S and impedancemeter Z–500PX 
(Elins Co). 
 
 
 A.A. VOLODIN, A.A. BELMESOV, E.V. GERASIMOVA, ET AL. PROC. NAP 1, 03CNN19 (2012) 
 
 
03CNN19-2 
3. RESULTS AND DISCUSSION 
 
To investigate the dependence of conductivity on 
the content of carbon nanomaterial mixtures contain-
ing from 1 to 5%(wt) of CNTs were prepared. After pro-
cessing in a planetary ball mill the samples of oxide 
powders and nanotubes had a homogeneous appear-
ance, however, at the study by electron microscopy in 
mixtures containing 1% and 2%(wt) CNTs, the tubes on 
their own are almost not observed. At the content of 
3%(wt) as bundles of nanotubes, as well as individual 
tubes could be observed. At the content of 5%(wt) a 
large number of nanotube bundles, distributed between 
the oxide particles were observed. This pattern was 
observed in the case of aluminum oxide, as well as in 
the case of titanium oxide (Fig. 1). 
 
 
 
Fig. 1 – TEM image of the composite MCNT/Al2O3, with 
5%(wt) of MCNT 
 
We selected optimal conditions for processing time, 
the degree of load, type and content of the carbon na-
nomaterial. Investigation of the electrical conductivity 
of composites based on Al2O3 with different content of 
carbon nanotubes have shown that the dependence is 
exponential. At the content of CNT 1 – 2%(wt) the elec-
trical conductivity remains practically unchanged and 
amounts to about 5×10-8 S/cm. The increase of the 
nanotubes content up to 5%(wt) leads to a sharp in-
crease in conductivity up to 3×10-4 S/cm. In this case 
one can observe a jump of conductivity at 3%(wt) to 
4.5×10-5 S/cm. In the case of TiO2 this effect also occurs 
at 3%(wt) of CNTs and the electrical conductivity of 
this composite is 2.2×10-3 S/cm. In general, the conduc-
tivity varies from 5×10-6 S/cm for pure TiO2 up to 
2.2×10-2 S/cm for the composite containing 5%(wt) of 
CNTs (Fig. 2). 
For selection of the optimum degree of load and 
milling time in the future we used a composite with 
3%(wt) of carbon nanostructures. The experiments re-
vealed that the highest conductivity of milled compo-
sites reached at 100 rpm, for 30 min (Fig. 3, 4). A fur-
ther increase in time or number of revolutions leads to 
a refinement of carbon nanostructures and, conse-
quently, reduces the conductivity. 
At the study of the electrical conductivity of compo-
sites according to the type of carbon nanostructures, it 
was found that the composites with multiwall carbon 
nanotubes have the best conductivity (Fig. 5), the conduc-
tivity of composites with single-walled carbon nanotubes 
(SWNT) is worse by two orders of magnitude; a composite 
with carbon nanofibers (CNF) has the worst conductivity. 
0 1 2 3 4 5
10
-9
10
-8
10
-7
10
-6
10
-5
10
-4
10
-3
10
-2  MWNT/TiO
2
 MWNT/Al
2
O
3
S
p
e
c
if
ic
 C
o
n
d
u
c
ti
v
it
y 
(S
/c
m
)
Content MWNT (%wt)  
 
Fig. 2 – Dependence of the conductivity of the composites 
MCNT/Al2O3 and MCNT/TiO2 on the mass content of carbon 
nanotubes 
 
100 200 300 400 500
10
-8
10
-7
10
-6
10
-5
10
-4
10
-3
S
p
e
c
if
ic
 C
o
n
d
u
c
ti
v
it
y 
(S
/c
m
)
Rotational Speed (rpm)  
 
Fig. 3 – Dependence of the conductivity of the composites 
TiO2/MCNT (3%wt) on the number of revolutions 
 
15 30 45 60
10
-6
10
-5
10
-4
10
-3
S
p
e
c
if
ic
 C
o
n
d
u
c
ti
v
it
y 
(S
/c
m
)
Time (min)  
 
Fig. 4 – Dependence of the conductivity of the composites 
TiO2/MCNT (3%wt) on the milling time 
 
For a detailed description of the formation condi-
tions of carbon-oxide composites in a planetary ball 
mill the magnitude of strain effect on the material was 
also determined during the machining method of the 
test sites and the energy transferred to the sample dur-
 ELECTRO-CONDUCTIVE COMPOSITES BASED ON METAL OXIDES … PROC. NAP 1, 03CNN19 (2012) 
 
 
03CNN19-3 
ing ball-milling was calculated [21]. This method uses a 
universal value that allows one to be independent on 
the type of mill and sufficiently facilitates the produc-
tion and optimization of the processes of formation of 
composite materials in conditions of a variety of grind-
ing and mixing machines. 
 
10
-6
10
-5
10
-4
10
-3
10
-2
 SWNT/TiO2MWNT/TiO2
S
p
e
c
if
ic
 C
o
n
d
u
c
ti
v
it
y 
(S
/c
m
)
CNF/TiO
2  
 
Fig. 5 – Dependence of the conductivity of the composites 
CNS/TiO2 (3%wt) on the type of carbon nanostructures con-
tained in it 
 
According to the results of calculations of the dose 
of strain effect and the data of the electrical conductivi-
ty of composites plots of the dependence of electrical 
conductivity of composites MWNT/TiO2 on the dose of 
strain effect on the samples were constructed (Fig. 6). 
 
30 100 1000 10000
10
-7
10
-6
10
-5
10
-4
10
-3
S
p
e
c
if
ic
 C
o
n
d
u
c
ti
v
it
y 
(S
/c
m
)
Dose of Strain Effects (J/g)  
 
Fig. 6 – Dependence of the conductivity of the composite 
MWNT/TiO2 on the dose of strain effect on the samples 
 
As can be seen from the figure, the samples ob-
tained by mechanical action 76 J/g have the highest 
conductivity (4.5×10-3 S/cm). Further increase of the 
load and processing time leads to a decrease in electri-
cal conductivity, which is obviously due to the oxide 
shredding and destruction of carbon nanotubes. This 
assumption is confirmed by the values of specific sur-
face area of the composites, which vary from 55 m2/g 
for the composites obtained at a dose of strain effect 
38 J/g to 80 m2/g for the composites obtained at 
9.6 kJ/g. A similar pattern is observed in the case of 
composites based on aluminum oxide. 
 
To evaluate the effectiveness of the use of CNT/TiO2 
composite as a carrier of catalysts in electrochemical 
devices Pt/TiO2-CNT samples with different contents of 
carbon nanotubes were prepared and their electrocata-
lytic activity was investigated using an electrode-
modeling cathode of a fuel cell. According to scanning 
electron microscopy Pt particles are distributed over 
the surface of titanium oxide fairly evenly. The average 
particle size is in the range 5-10 nm (Fig. 7). According 
to the EDX Pt content is at a level of 10%(wt). 
 
 
 
Fig. 7 – SEM image of TiO2 with Pt clusters deposited on it 
 
Current-voltage characteristics of the system 
Pt/TiO2 – CNT with different mass content of carbon 
nanotubes are shown on Figure 8. 
 
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20
0
100
200
300
400
500
600
700
800
900
 Pt/TiO2+MWNT(50%)
 Pt/TiO2+MWNT(15%)
 Pt/TiO2+MWNT(3%)
 Pt/TiO2+MWNT(5%)
P
o
te
n
ti
a
l (
m
V
)
Current Density (A/cm
2
)  
 
Fig. 7 – SEM image of TiO2 with Pt clusters deposited on it 
 
The composite with 5%(wt) of MWNT is the most ef-
fective. The composite with 3%(wt) content of CNT has 
lower quantity of extended carbon structures providing 
electron transport, and in samples with 15 and 50%(wt) 
of CNT the low efficiency of Pt-catalyst may be related 
to difficulties of contact with the reaction medium be-
cause of the large amount of carbon material. 
According to literature data, at the presence of 
spherical particles of the conducting phase and parti-
cles of non-conductive matrix of the same size for the 
occurrence of the percolation the content of the con-
ducting phase should be at the level of 50%. In the case 
of ellipsoidal particles this content reduces to 20-30%. 
For filamentous particles, this value is usually less 
 A.A. VOLODIN, A.A. BELMESOV, E.V. GERASIMOVA, ET AL. PROC. NAP 1, 03CNN19 (2012) 
 
 
03CNN19-4 
than 10%. In the case of composites obtained by the 
synthesis of carbon nanostructures directly on the sur-
face of oxide powders, apparently, there is a tight con-
tact both between the carbon tubes and between tubes 
and particles of oxides. 
 
CONCLUSIONS 
 
Optimal conditions were determined for the for-
mation of carbon-oxide composites by the treatment of 
mixtures of oxides of a metal with carbon nanomateri-
als in a planetary ball mill. The dependences of the 
electrical conductivity of composites on the content of 
carbon nanomaterials (1–5%wt) were determined. It is 
established that the addition of 3%(wt) of CNT to the 
oxides leads to a sharp increase in the electrical con-
ductivity: from 5.0×10-8 to 2.8×10-4 S/cm for Al2O3 and 
from 5.0×10-6 to 2.2×10-2 S/cm for TiO2. It was shown 
that the carbon-oxide composites are promising carri-
ers of the catalysts of electrode processes in electro-
chemical devices. It was revealed that Pt/TiO2 – CNT 
catalyst containing 5%(wt) of carbon nanotubes has the 
best catalytic activity in oxygen reduction, in an elec-
trode-modeling cathode of a fuel cell. 
 
AKNOWLEDGEMENTS 
 
The work was supported by RFBR (Project № 11-
03-90454 Ukr_f_a) and by the Program OChNM-02. 
 
REFERENCES 
 
1. Composites: ASM Handbook (Ed. D.B. Miracle, S.L. Don-
aldson) (ASM International: The Materials Information 
Company: 2001). 
2. J.A. Arsecularatne, L.C. Zhang, Recent Patents on Nano-
tech. 1, 176 (2007). 
3. D. Eder, Chem. Rev. 110, 1348 (2010). 
4. Y.V. Blagoveschensky, K.V. Van, A.A. Volodin, V.M. Kiiko, 
A.A. Kolchin, N.I. Novokhatskaya, B.P. Tarasov, A.N. 
Tolstun, Composites and Nanostructures 1, 30 (2010). 
5. B.P. Tarasov, V.E. Muradyan, A.A. Volodin, Russ. Chem. 
Bull. 60, 1261 (2011). 
6. Yu. Fan, L. Wang Carbon 48, 1743 (2010). 
7. A.M. Bondar, I. Iordache, J. Optoelectronics and Adv. Ma-
ter. 8, 631 (2006). 
8. F-H.Su, Zh-Zh.Zhang, K.Wang, Composites: Part A 37, 
1351 (2006). 
9. B. Fényi, N. Hegman, F. Wéber, Processing and Applica-
tion of Ceram. 1–2, 57 (2007). 
10. G-B. Zheng, H. Sano, Y. Uchiyama, Composites: Part B 42, 
2158 (2011). 
11. S.Q. Guo, R. Sivakumar, H. Kitazawa, Y.Kagawa, J. Am. 
Ceram. Soc. 90, 1667 (2007). 
12. J. Yu, J. Fan, B. Cheng, J. Power Sources 196, 7891 
(2011). 
13. O.Yu. Ivanshina, M.E. Tamm, E.V. Gerasimova, Inorg. 
Mater. 47, 618 (2011). 
14. C. Martínez, M. Canle, M.I. Fernándeza, Appl. Catal. B: 
Environmental 102, 563 (2011). 
15. X.L. Li, C. Li, Y. Zhang, Nanoscale Res. Lett. 5, 1836 
(2010). 
16. L.Q. Jiang, L.Gao, J. Mater. Chem. 15, 260 (2005). 
17. S.L. Shi, J. Liang, J. Appl. Phys. 101, 023708 (2007). 
18. Zh-Sh. Wu, G. Zhou, Li-Ch. Yina, Nano Energy 1, 107 
(2012). 
19. B.P. Tarasov, V.E. Muradyan, A.A. Volodin, Fullerenes 
and Nanostructures in Condensed Matter (Minsk: Publish-
ing Center BSU: 2011). 
20. A.A. Volodin, D.V. Chihirev, A.D. Zolotarenko, D.V. Schur, 
B.P. Tarasov, Fullerenes and Nanostructures in Condensed 
Matter (Minsk: Publishing Center BSU: 2011). 
21. P.Yu. Butyagin, A.N. Streletskii, Phys. Solid State 47, 856 
(2005).
 


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Electro-Conductive Composites Based on Metal Oxides and Carbon Nanostructures

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