Revista de Ciencias Tecnológicas (RECIT). Volumen 3 (1): 10-22.
Revista de Ciencias Tecnológicas (RECIT). Universidad Autónoma de Baja California ISSN 2594-1925
Volumen 2 (1): 40-44 Enero-Marzo 2019 https://doi.org/10.37636/recit.v214044
40
ISSN: 2594-1925
Evaluation of cobalt nanoparticle deposited
graphene oxide and carbon nanotube supports as
supercapacitor electrodes
Evaluación del óxido de grafeno depositado en nanopartículas
de cobalto y soportes de nanotubos de carbono
como electrodos supercondensadores
Aguilar-Meza David Ricardo
1
, Salazar-Gastélum Moisés Israel
1*
, Pérez-Sicairos Sergio
1, 2
,
Félix-Navarro Rosa María
2
, Gochi-Ponce Yadira
1,2*
1
Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, Posgrado en Ciencias de la Ingeniería,
Blvd. Industrial S/N. C. P. 22500. Tijuana, Baja California, México.
2
Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, Centro de Graduados
e Investigación en Química, Blvd. Industrial S/N. C. P. 22500. Tijuana, Baja California, México.
Autores de correspondencia: Moisés Israel Salazar Gastélum, Tecnológico Nacional de México, Instituto
Tecnológico de Tijuana, Posgrado en Ciencias de la Ingeniería, Blvd. Industrial S/N Tijuana, B. C. México, C.
P. 22500. E-mail: moises.salazar@tectijuana.edu.mx. Yadira Gochi Ponce, Tecnológico Nacional de México,
Instituto Tecnológico de Tijuana, Posgrado en Ciencias de la Ingeniería, Blvd. Industrial S/N Tijuana, B. C.
México, C. P. 22500. Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, Centro de Graduados
e Investigación en Química, Blvd. Industrial S/N Tijuana, B. C. México, C. P. 22500. E-mail:
yadira.gochi@tectijuana.edu.mx. ORCID: 0000-0002-1590-2432 .
Recibido: 15 de Agosto del 2018 Aceptado: 02 de Enero del 2019 Publicado: 15 de Febrero del 2019
Resumen. - Las nanopartículas de cobalto se depositaron en soportes de carbono, nanotubos de carbono de
pared ltiple (CNT) y óxido de grafeno (GO), y se evaluaron como potenciales electrodos de
supercondensadores. La estructura y la morfología de las nanopartículas de cobalto depositadas sobre los
soportes de carbono se estudiaron mediante XRD, TGA y espectroscopía Raman. La voltametría cíclica se
utilizó para medir la carga eléctrica del electrodo en función de los materiales y se calculó su capacitancia
específica (Csp). El electrodo basado en GO mostró un Csp mayor que el electrodo CNT, lo cual se atribuye a
un área de superficie mayor del soporte de carbono GO. Curiosamente, el depósito de nanopartículas de Co
promovió una Csp mejorada en los soportes GO y en los CNT de pared múltiple.
Palabras clave: Supercondensador; Óxido de Grafeno; Nanotubos de Carbono; Nanopartículas de Cobalto.
Abstract. - Cobalt nanoparticles were deposited on multi-wall carbon nanotubes (CNT) and graphene oxide
(GO) carbon supports and evaluated as a potential supercapacitor electrodes. The structure and morphology
of the cobalt nanoparticles deposited on carbon supports were studied using XRD, TGA, and Raman
spectroscopy. Cyclic voltammetry was used to measure the electrical charge of the electrode based on the
materials and their specific capacitance (Csp) were calculated. GO based electrode showed a higher Csp than
CNT electrode which is attributed to a larger surface area of the GO carbon support. Interestingly, the
deposition of Co nanoparticles promoted an enhanced Csp in the both GO and multi-wall CNT supports.
Keywords: Supercapacitor; Graphene Oxide; Carbon Nanotubes; Cobalt Nanoparticles.
Revista de Ciencias Tecnológicas (RECIT). Volumen 2 (1): 40-44
41
ISSN: 2594-1925
1. Introducción
Energy demand has always been a primary area of
interest around the world and its claim has grown
very fast in recent years. Considerable effort has
been dedicated to the research and development of
more efficient energy storage devices and systems
[1].
The bulk of energy storage research has been
focused on two types of electrochemical devices:
batteries and capacitors. Batteries have low power
density with higher energy density, while
conventional capacitors exhibited high power but
lower energy density. On the other hand,
supercapacitors (SCs) are efficient devices that
have exceeded the energy storage capacity with
respect to conventional capacitors. The SCs have
great advantages including their high-power
density, long service life, wide operating
temperature range, flexibility, and their
ecofriendly nature. Some applications for these
devices are in areas like consumption electronic,
hybrid vehicles, and industrial power/energy
managements [2]. However, SCs suffer from low
energy density and high manufacturing cost.
Conventionally, the capacitive behavior can be
classified into two types; (1) the double layer
electric capacitance (EDLC) arising from
electrostatic attraction between electrolyte and
electrode surface; (2) the pseudo-capacitance
associated with fast and reversible faradic
reactions of the active species on the surface of the
electrode.
One way to attain better performance for
capacitors is to increase the capacitance (C).
Capacitance is directly influenced by the dielectric
constant of the electrolyte, (ε
r
), the effective
thickness of the double layer (d, separation
between
charges), the dielectric constant of the
vacuum (ε
0
)
and the surface area (A):
𝐶 =
𝜀
𝑟
𝜀
0
𝐴
𝑑
(1)
The use of nanomaterials such as graphene oxide
(GO) and multi-wall carbon nanotubes (CNT) can
provide a synergistic effect on capacitance and
thereby energy density and the deposition of
nanoparticles is expected to increase this synergic
effect. Typically, noble metal oxides such as RuO
2
have exhibited exceptional properties as pseudo-
capacitor materials for capacitors. The high cost
of Ru has thwarted its commercial acceptance as
an electrode material in SCs and encouraged
finding other cheaper materials with a similar
capacitive behavior as RuO
2
[3]. Cobalt appears
as a possibility to increase the energy storage by
the phenomenon of pseudo-capacitance [reference
needed]. We propose the use of GO and CNT
modified deposited with Co nanoparticles in order
to obtain a non-expensive and efficient material
for SCs.
2. Methodology
In this work, GO was synthesized by Hummers
modified method [4] and CNT were synthesized
by spray pyrolysis [5]. Nanoparticles of cobalt
were deposited on both carbonaceous supports by
the method of reverse microemulsion [6].
2.1 Preparation of GO, CNT, Co/GO and
Co/CNT
Hummers modified method consists of the
exfoliation of graphite powder in strongly
oxidizing media. 2 g of the natural graphite
powder was added into a 250-mL beaker with 1 g
of NaNO
3
. 46 mL of H
2
SO
4
were subsequently
added to the graphite powder mixture under
stirring in an ice-bath. Then, 6 g of KMnO
4
was
added slowly into the beaker while stirring and the
temperature of the system was maintained at 20
°C using an ice-bath. After 5 min, the ice bath was
removed and the system was heated (what
temperature?) for 30 min followed by an addition
of 92 mL of and the mixture was stirred for 15
min. Then, 80 mL of hot water at 60 °C and H
2
O
2
aqueous solution (3 wt %) were added to the
mixture until the bubbling disappeared. Finally,
the system was centrifuged for 30 min, and the
Revista de Ciencias Tecnológicas (RECIT). Volumen 2 (1): 40-44
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ISSN: 2594-1925
residue was washed with warm water until the
suspension was neutralized.
In spray pyrolysis, a quartz tube was placed inside
of an oven at 850 °C while a solution of 20 mM of
ferrocene in toluene was sprayed out by Ar flow
at 20 psi. After the reaction was allowed to
proceed for 30 min, the oven cooled down to room
temperature with Ar flow. CNTs were
functionalized by acidic solution of H
2
SO
4
:HNO
3
with a ratio 1:3 M.
The deposition of Co nanoparticles was performed
by reverse microemulsion method which starts
with the preparation of a microemulsion solution
of isopropanol/CTAB/ H
2
O (56 mL/2 g/4 mL). 40
mL of microemulsion solution were taken in order
to disperse the support (either CNT or GO) under
sonication. Then, the dispersion was placed in a
round bottom flask under stirring at 60 °C. After
15 min, a mixture of 2 mL of aqueous solution
containing 100 mM of sodium borohydride and
100 mM of sodium citrate was prepared and added
with 10 mL of the above microemulsion solution.
After 20 min, 12 mg of cobalt (II) chloride salt
dispersed in 2 mL of H
2
O was slowly added into
the original 10 mL of microemulsion solution by
sonication and the reaction vessel was kept at
reflux for 90 min. Finally, the residue was filtered
and washed with DI water, isopropanol, and
ketone.
2.2 Characterization
The structure and morphology of nanocomposites
were characterized by Raman spectroscopy, X-ray
diffraction and thermogravimetric analysis. The
electrochemical properties of nanomaterials and
their correlation with the nanoparticles were
investigated using a three-electrode cell using
techniques such as cyclic voltammetry (CV) and
electrochemical impedance spectroscopy (EIS).
Glassy carbon (GC) was used as working
electrode (3 mm of diameter), Au wire was used
as counter electrode, and Ag/AgCl/KClsat was
used as reference electrode.
3. Results and Discussions
TGA curves were used to understand the thermal
decomposition behavior of the two different
supports used in this study. CNT showed a
thermal decomposition at 633 °C, while GO
exhibited the thermal decomposition at 188 °C.
CNT-F (What is CNT-F? should explain that first)
showed a thermal behavior similar to CNT but
showed decomposition at 320 °C, due to
desorption of oxygen functional groups. Besides,
the metal loading of both Co/CNT and Co/GO was
estimated by TGA analysis as 12% and 19%
respectively.
Figure 1. TGA curves of the synthesized materials.
Raman spectroscopy is useful for studying order
and defects in crystal structure and is often
employed to characterize carbonaceous materials
[reference needed]. The G band is common for all
sp2 carbon forms and it arises from the C-C bond
stretch. This band is formed from first order
Raman scattering and the D band is associated
with disordered structural defects [7]. The ratio of
the intensities of D and G bands is an indicator of
the quality of bulk samples. Similar intensities of
these bands indicate a high quantity of structural
defects. Raman spectra of the synthetized
materials exhibited a peak of D band at 1334 cm
-
1
, 1336 cm
-1
, 1350 cm
-1
and 1323 cm
-1
and G band
at 1586 cm
-1
, 1582 cm
-1
, 1603 cm
-1
and 1594 cm
-1
for CNT, Co/CNT, GO, and Co/GO, respectively.
Revista de Ciencias Tecnológicas (RECIT). Volumen 2 (1): 40-44
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ISSN: 2594-1925
The G band in GO is shifted to a higher wave
number due to the oxygenation of graphite, which
results in the formation of sp3 carbon atoms. The
D band in GO is broadened due to the reduction in
size of the sp2 domains by the creation of defects,
vacancies, and distortions during oxidation. In
order to confirm the formation of multi-wall
carbon nanotubes, the ratio of the intensities of D
and G bands present values characteristic for
multi-wall carbon nanotubes. Also, the Raman
spectrum from 250 nm to 350 nm does not
exhibited any signal (not shown), which is typical
for this structure [8].
Figure 2. Raman spectra of CNT, Co/CNT (A) and GO, Co/GO
(B).
The deposition of the Co nanoparticles clearly
shows an increase in ID/IG ratio. The ID/IG ratio
of CNT is 0.50 while that of Co/CNT 0.74.
Similarly, the ID/IG ratio of GO is 0.98 while that
if Co/GO is 1.21 showing that more defects appear
after Co deposition.
Figure 3 showa the XRD pattern for all the
material synthetized. For CNT and Co/CNT, a
strongest peak appearing at the angle (2θ) of 26°
is the C(002) reflection of the hexagonal graphite
structure and the peak on 43° is are related with
C(100) [9]. This reflection of the hexagonal
graphite structure does not appear for GO or
Co/GO.
Figure 3. XRD Patterns of CNT, Co/CNT, GOx, and
Co/GOx.
CV curves were performed at different potential
scan rates in order to obtain the integrated charge
and to calculate the specific capacitance (Csp)
according to equation 2:
C
sp
= ____ 𝑄 _____
2
∗𝑚∗
𝑉∗𝜈
(2)
Where, Q is the integrated charge of CV curve
(mC), m is the nanomaterial loading (mg), ΔV is
the potential window (mV), and ν is the scan rate
potential (mV s
-1
). Figure 3 shows the Csp vs. scan
rate potential of CNT, GO, Co/CNT and Co/GO.
Figure 4. C
sp
vs. scan rate of the synthesized materials.
When comparing the carbon supports, GO showed
higher Csp than CNT. However, when Co
nanoparticles are deposited on to the supports, the
Csp increases more for Co/GO but remains
constant for Co/CNT. The C vs. Log frequency
plot could be used to identify the geometrical
capacitance and the dielectric constant of any
materials [10] accordingly to Equation 1.
Revista de Ciencias Tecnológicas (RECIT). Volumen 2 (1): 40-44
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ISSN: 2594-1925
Figure 5. Cvs. Log (Freq) of the synthesized materials.
The capacitance of all the materials were
estimated from Figure 5 and the dielectric
constant of the materials are of the same order.
4. Conclusions
Co nanoparticles were deposited onto CNT and
GO supports. The nanomaterials synthesized were
characterized using XRD, TGA, and Raman
showed a higher surface area for Co/GO. Based on
the CV results, Co/GO exhibited the highest Csp
among all the materials studied which is attributed
the large surface area of GO and the contribution
of pseudo- capacitance from Co nanoparticles.
5. Acknowledgments
The authors are grateful for the technical support of
Silva-Pereira H. and Rivera B. from LINAN- IPICYT.
Authors would like to thank to Dr. Samgopiraj Velraj
from Ohio University for his invaluable help in the
revision process of this publication. Founding source
for this work was sponsored from Tecnológico
Nacional de México (TECNM) through the program
“Apoyo a la Investigación Científica, Aplicada y
Desarrollos Tecnológicos 2016” (project number
5870.16-P).
Referencias
[1] M. Vangari, T. Pryor, and L. Jiang, "Supercapacitors: Review
of materials and fabrication methods," J. Energy Eng., vol. 139, no.
2, pp. 72-79, 2013. https://doi.org/10.1061/(ASCE)EY.1943-
7897.0000102
[2] C. Zhao and W. Zheng, "A Review for Aqueous
Electrochemical Supercapacitors," Front. Energy Res., vol. 3, no.
May, pp. 1-11, 2015. https://doi.org/10.3389/fenrg.2015.00023
[3] Z. Fan, J. Chen, K. Cui, F. Sun, Y. Xu, and Y. Kuang,
"Preparation and capacitive properties of cobalt-nickel
oxides/carbon nanotube composites," Electrochim. Acta, vol. 52,
no. 9, pp. 2959-2965, 2007.
https://doi.org/10.1016/j.electacta.2006.09.029
[4] W. Chen, L. Yan, and P. R. Bangal, "Preparation of graphene
by the rapid and mild thermal reduction of graphene oxide induced
by microwaves," Carbon N. Y., vol. 48, no. 4, pp. 1146- 1152,
2010. https://doi.org/10.1016/j.carbon.2009.11.037
[5] A. Aguilar-Elguézabal, W. Antúnez, G. Alonso, F. P. Delgado,
F. Espinosa, and M. Miki- Yoshida, "Study of carbon nanotubes
synthesis by spray pyrolysis and model of growth," Diam. Relat.
Mater., vol. 15, no. 9, pp. 1329-1335, 2006.
https://doi.org/10.1016/j.diamond.2005.10.011
[6] M. Beltrán Gastélum, "Síntesis y caracterización de
electrocatalizadores nanoestructurados y su aplicación en celdas de
combustible a escala prototipo," Instituto Tecnológico de Tijuana,
2016.
[7] S. Perumbilavil, P. Sankar, T. Priya Rose, and R. Philip,
"White light Z-scan measurements of ultrafast optical nonlinearity
in reduced graphene oxide nanosheets in the 400-700 nm region,"
Appl. Phys. Lett., vol. 107, no. 5, pp. 10-15, 2015.
https://doi.org/10.1063/1.4928124
[8] M. A. Atieh, O. Y. Bakather, B. Al- Tawbini, A. A. Bukhari,
F. A. Abuilaiwi, and M. B. Fettouhi, "Characterization of carbon
nanotubes by Raman spectroscopy," Bioinorg. Chem. Appl., vol.
2010, no. 2, pp. 1-9, 2010. https://doi.org/10.1155/2010/603978
[9] T. A. Saleh, The Role of Carbon Nanotubes in Enhancement of
Photocatalysis, in Syntheses and Applications of Carbon
Nanotubes and Their Composites, S. Suzuki, Ed. Rijeka: InTech,
2013. https://doi.org/10.5772/51050
[10] V. V. Brus, A. K. K. Kyaw, P. D. Maryanchuk, and J. Zhang,
"Quantifying interface states and bulk defects in high-efficiency
solution- processed small-molecule solar cells by impedance and
capacitance characteristics," Prog. Photovoltaics Res. Appl., vol.
23, no. 11, pp. 1526- 1535, Nov. 2015.
https://doi.org/10.1002/pip.2586
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