Electrochemical evaluation of Pt/GMC and Pt/rGO for the electro-oxidation of methanol

1. Electrochemical evaluation of Pt/GMC and Pt/rGO
for the electro-oxidation of methanol
David Macias Ferrer, José Aarón Melo Banda,
Ulises Páramo García, Mayda Lam Maldonado,
Rebeca Silva Rodrigo
Division of Graduate Studies and Research
Technological Institute of Ciudad Madero
Cd. Madero Tamaulipas, México
e-mail: maestro_macias@hotmail.com
José Ysmael Verde Gomez
Division of Graduate Studies and Research
Technological Institute of Cancún
Cancún Quintana Roo, México
Iván Alziri Estrada Moreno
Department of Engineering and Materials Chemistry
Research Center for Advanced Materials
Chihuahua Chihuahua, México
Abstract— In this work, Pt/GMC and Pt/rGO electrocatalysts
have been prepared by impregnation reduction method in which
Pt precursor is chemically reduced by citric acid, ethanol and Ar-
H2 dynamic atmosphere. Graphitic mesoporous carbon (GMC)
sample was synthesized via nanocasting process with anhydrous
pyrolysis at 1273 K using SBA-15 as hard template and purified
sugar as carbon source. SBA-15 was prepared via sol gel using
pluronic P-123 as surfactant and TEOS as silica precursor.
Reduced graphene oxide (rGO) was synthesized by modified
Hummers method using graphite as carbon precursor. The
prepared materials were characterized by means of diffraction
(XRD), scanning electron microscopy (SEM), energy-dispersive
X-ray spectroscopy (EDS) and high resolution transmission
electron microscopy (HRTEM). The performance of
electrocatalysts for methanol oxidation reaction (MOR) was
measured by cyclic voltammetry (CV). The electrochemical
characterization techniques revealed that the mass activity of
Pt/GMC, Pt/rGO and the commercial electrocatalyst Pt/C were
627, 332 and 371 mA/mgPt respectively as well as the carbon
monoxide tolerance index ICO for these catalysts were 1.07, 1.04
and 0.76 respectively. Therefore, Pt/GMC shows better
electrocatalytic performance and best resistance to carbonaceous
intermediates species for the electrooxidation of methanol.
Keywords: Electrocatalysts, Mesoporous carbon, graphene
oxide, methanol electrooxidation
I. INTRODUCTION
Fuel cells are devices that convert with high efficiency, the
power of electrochemical reactions into electricity. In recent
years, Polymer electrolyte membrane fuel cells (PEMFC) is
one of the most studied devices. The direct methanol fuel cell
(DMFC) is a special form of low-temperature fuel cells based
on PEM technology [1]. DMFC have attracted significant
attention because of their high theoretical power density, high
energy conversion efficiency, low environmental pollution and
easy refueling, being one of the potential power source for
portable electronic devices [2-5]. The high reactivity of
methanol with platinum and the excellent catalytic activity for
electro-oxidation of methanol on pure Pt especially at low
temperature (below 80°C), makes this metal a suitable anodic
electrocatalyst in DMFC [6]. However, it is well known that
there is a series of technical problems in DMFC that limit their
marketing [7]. While Pt, which is generally supported on
activated carbon with large surface area such as Vulcan XC-72,
is the best catalyst for the electro-oxidation of methanol, it
rapidly becomes poisoned because of the intermediate species
formed during the oxidation of methanol, mainly CO, since CO
molecules can be chemically adsorbed on the surface of Pt and
block the active sites, producing a poor kinetic of anodic
methanol oxidation due to CO poisoning and a low
electrocatalytic activity of electrocatalysts [8-11]. Although
electrocatalysts based on Pt and Pt-Ru alloy have shown a
good catalytic activity for electro-oxidation of methanol,
another of the limitations in the development of DMFC for
commercial applications is the high cost of both noble metals
[12-13]. Therefore, many efforts have focused on the
development of techniques and new electrocatalysts to achieve
enhancing the electrocatalytic activity by inhibiting the CO
poisoning effect according the bifunctional mechanism and
reducing cost of the electrocatalysts [14]. One of the main
components of the electrocatalyst that contributes to the high
electrocatalytic activity in MOR, is the nature of the carbon
material support, which can help in dispersing the metal
catalyst and in facilitating electron transport, as well as in
promoting mass transfer kinetics at the electrode surface. Thus,
several carbon materials such as highly conductive carbon
blacks (CBs) of turbostratic structures with high surface areas
(Vulcan XC-72R, Shawinigan, Black Pearl 2000, Ketjen Black
and Denka Black) and carbon nanostructures like mesoporous
carbon, carbon nanotubes (CNTs), nanodiamonds, carbon
nanofibers (CNF), ordered mesoporous carbon (OMC),
reduced graphene oxide (rGO) and graphene, have been tested
[15-16]. In this paper, we propose the use of catalytic supports,
graphitic mesoporous carbon (GMC) and reduced graphene

2. oxide (rGO), making the electrocatalysts Pt/GMC and Pt/rGO
in order to measure their electrocatalytic activity towards the
methanol electro-oxidation in acid media.
II. MATERIAL AND METHODS
A. Chemicals
Methanol (CH4O, 99.9%) was supplied by J.T. Baker.
pluronic P123 (non-ionic triblock copolymer, EO20PO70O20),
tetraethoxysilane (Si(OC2H5)4, 98%), platinum (II)
acetylacetonate (Pt(C5H7O2)2, 97%), platinum on graphitized
carbon 20% wt loading (Pt/C), graphite powder (99.99%),
nafion 117 solution, were obtained from Sigma-Aldrich;
deionized water, sulfuric acid (H2SO4, 98%), hydrofluoric acid
(HF, 40%), hydrochloric acid (HCl, 37%), nitric acid (HNO3,
70%), acetone (C3H6O, 99.5%), ethyl Alcohol (C2H6O,
99.7%), citric acid (C6H8O7, 99.5%), potassium permanganate
(KMnO4, 99%), sodium nitrate (NaNO3, 99%), hydrogen
peroxide (H2O2, 30%) were supplied by Fermont; refined sugar
were obtained by Del Marques; ultrapure water (15 MΩcm-1
)
was generated by ELGA Purelab Option station.
B. Synthesis of Pt/GMC
SBA-15 sample was synthesized according to the standard
procedure [17] with some modifications. In a typical synthesis,
2.0 g Pluronic 123 as a structure-directing agent were dissolved
in 14 mL deionized water and 60 mL 0.6 M hydrochloric acid
by stirring at room temperature for 5 h. Afterwards, 4.3 mL of
tetraethoxysilane (TEOS) were added dropwise and the
mixture was stirred (700 rpm) at 45 °C for 24 h in the closed
glass reactor. After, the mixture was aged in oven at 90 °C for
24 h. The white powder was obtained through filtration,
washing and drying in nalgene bottle under vacuum. Finally,
the sample was calcined at 550 °C for 6 h under air to remove
the surfactant to obtain the silica template. GMC sample was
synthesized using a nanocasting pathway using pure silica
SBA-15 as hard template and refined sugar as carbon precursor
according to the procedure reported in the literature [18-19]
with some modifications. In brief: 1 g of refined sugar and 1 g
of SBA-15 were dissolved in 5 mL of deionized water by
stirring at room temperature for 30 min, during this time 0.05
ml of sulfuric acid were added. The mixture was heated in a
oven at 100 °C for 6 h, and subsequently 160 °C for another 6
h. The silica sample, containing partially polymerized and
carbonized refined sugar, was carbonized in a quartz furnace at
1000 °C for 1 h under N2 flow. After pyrolysis, the silica
template was removed under vigorous stirring using
concentrated HF at the room temperature for 2 h. Afterwards
the black powder was obtained through filtration, washing with
ultrapure water and drying in a oven at 80 °C for 12 h. The
functionalization process for GMC, was carried out in soxhlet
equipment by refluxing GMC in 1M HNO3 + 1M H2SO4 at 110
°C by 5 h in order to generate surface oxides such as
carboxylic (–COOH), carbonyl (–C=O), and hydroxyl (–C–
OH) groups on the support surface. Afterward, the mixture was
diluted with ultrapure water, filtered, washed with excess
ultrapure water, and dried in N2 at 150 °C in a tubular furnace
by 2 h [20]. Platinum nanoparticles with 20 wt% loading were
supported on the GMC by a wet chemical reduction at incipient
wetness impregnation method. A detailed procedure is as
follows: An appropriate amount of Pt(C5H7O2)2 were dissolved
in 20 mL of acetone and simultaneously 0.32 g of GMC
(oxidized) were dissolved in 30 mL of ethyl alcohol. Both are
mixed under mechanical stirring at room temperature until a
homogeneous mixture. Then the dispersion was ultrasonicated
for 30 min. Afterwards, the mixture is kept under mechanical
stirring for 5 h at room temperature with an Ar-H2 (90%-10%)
atmosphere in order to remove isolate oxygen. After reaction,
the obtained products were filtrated, washed with ultrapure
water and then vacuum dried. The impregnated carbon sample
was heated in a quartz furnace a flowing Ar-H2 environment
while increasing temperature from the room temperature to 250
°C over 1 h then to 400 °C over 2 h. The result sample denoted
Pt/GMC electrocatalyst [21-22].
C. Synthesis of Pt/rGO
Graphene oxide (GO) was synthesized from graphite
powder using modified Hummer’s method. In brief, 1 g of
graphite and 0.5 g of sodium nitrate were mixed together
followed by the addition of 23 mL of concentrate sulphuric
acid under constant stirring. After 1 h, 3 g of KMnO4 was
added gradually to the above solution while keeping the
temperature less than 20°C to prevent overheating and
explosion. The mixture was stirred at 35 °C for 12 h and the
resulting solution was diluted by adding 500 mL of water
under vigorous stirring to ensure the completion of reaction
with KMnO4. The suspension was further treated with 30%
H2O2 solution (5 mL). The resulting mixture was washed with
HCl and ethanol respectively, followed by filtration and
drying, graphene oxide sheets were thus obtained [23]. For the
synthesis of Pt/rGO, it applies exactly the same procedure
described for Pt/GMC.
D. Characterization techniques and electrochemical
measurements
XRD patterns were collected on a Bruker D8 Advance X-
ray diffractometer with Cu Kα radiation. SEM characterization
was performed using a JEOL model JSM-7100F operating in
SEM and GB-Low modes at 20 keV and 2 KeV respectively
and EDS detector from Oxford Instruments. The performance
of electrocatalysts and commercial catalyst (P/C) for room
temperature methanol oxidation reaction was measured in
electrochemical work station BASi-epsilon (potentiostat/
galvanostat). A conventional three-electrode cell consisting of
the glassy carbon (GC) working electrode, Pt wire as counter
electrode and Ag/AgCl reference electrode were used for the
cyclic voltammetry studies. A glassy carbon electrode (3 mm
in diameter) was sequentially polished with 0.05 μm Al2O3 and
then washed. The catalyst ink was prepared by ultrasonically
dispersing 10 mg catalyst in 1 mL of ethanol and 60μL
Nafion/water (25% Nafion) for 45 min. 10 μL of the dispersion
was transferred onto the GC and then dried in the air for 30
min. The electrolyte solution for methanol oxidation reaction
consists of 0.5 M CH3OH and 0.5 M H2SO4 and the CV’s were
recorded at a scanning rate of 30 mV/s and 20 cycles for each.
III. RESULTS AND DISCUSSION
XRD patterns for Pt/rGO and Pt/GMC electrocatalysts are
shown in Fig. 1. For both cases, the diffraction peaks at 39°,
46°, 68°, 81° and 86° were due to Pt (111), (200), (220), (311)
and (222) reflections respectively, which confirmed a face
centered cubic structure of Pt (JCPDS 071-3756) and are in

3. good agreement with the literature [24-25]. There was no
evidence of peaks related to platinum oxide.
Fig. 1. XRD pattern of Pt/rGO and Pt/GMC
The metal crystallite size were calculated from Pt(111)
reflection according to the Debye-Scherrer equation: DXRD =
0.94λ/(B2θcosθmax), where DXRD is the crystallite size, λ is the
X-ray wavelength (0.154 nm), B2θ is the full width at half
maximum and θmax is the angle at peak maximum. The
crystallite size for Pt/rGO and Pt/GMC were 13.7 and 11.7 nm
respectively [26].
Fig. 2a, shows an SEM image of GMC illustrating a rope-
like morphology that consist in graphene sheets with
turbostratic structure and EDS spectrum which shows the
elemental chemical composition of the graphitic mesoporous
carbon with negligible traces of F (0.78% wt) and Si (0.1%
wt). An SEM image of Pt/GMC showing a high dispersion of
Pt nanoparticles on the catalyst support, as well as the EDS
spectrum revealed the presence of Pt are illustrated in Fig. 2b.
The Fig. 2c, shows an SEM image of GO illustrating a laminar
morphology that consist in graphene sheets and EDS spectrum
which shows the elemental chemical composition of the
graphene oxide with negligible traces of K (0.12% wt) and S
(0.31% wt). Finally, an SEM image of Pt/rGO showing a high
dispersion of Pt nanoparticles on the catalyst support, as well
as the EDS spectrum revealed the presence of Pt are illustrated
in Fig. 2d. This is in accordance with the reported in literature
[27-30]. With respecto to electrocatalysts, the particle size
distribution (inset in figures 2b and 2d) were carried out by a
count of about 200 particles in both cases, concluding that the
average particle size for Pt/rGO and Pt/GMC were 12.46 and
13.8 nm respectively [31-32].
The electrocatalytic activity given by mass activity (the
current density is normalized to the platinum loading on the
electrodes) of the electrocatalysts Pt/rGO, Pt/GMC and
commercial catalysts Pt/C for room temperature methanol
oxidation reaction, were obtained by cyclic voltammetry in a
conventional three-electrode cell using the conditions
described above. In all cases, typically features of methanol
oxidation were observed, that is, two oxidation peaks
corresponding to the oxidation of methanol and intermediate
carbonaceous species (ICS), which occurred at around 0.75 V
and 0.55 V respectively (Fig. 3).
The chemisorbed CO specie is considered as a poisoning
on pure Pt surface, and are more difficult to oxidize that all
intermediate carbonaceous species formed during the methanol
oxidation reaction (MOR); to free the pure platinum, is
necessary to dissociate the water molecules and cause the
oxidation of CO to CO2, however, this is achieved at high
values of potential [33]; it has been shown that the incursion of
a second metal (i.e., Ruthenium) [34] or hydroxyl and carboxyl
functional groups anchored to the catalytic support [35], can
dissociate water molecules at very low potential, and contribute
to the release of the active sites of Pt increasing the
electrocatalytic activity in the MOR. Currently this process is
known as bifunctional mechanism theory [36-37].
On the other hand, the ratio of the forward anodic peak
current (If) to the reverse anodic peak current (Ib) denoted by
ICO, was used to measure the tolerance of electrocatalyst to
accumulation of ICS, particularly CO; a higher ratio indicates
more effective removal of the poisoning species on the catalyst
surface [38].
Fig. 2. SEM images and EDS profiles of a) GMC; b) Pt/GMC; c) GO; d) Pt/rGO

4. According to what explained above and the experimental
results, the electrocatalyst Pt/GMC had higher electrocatalytic
activity (627 mA/mgPt) and better antipoisoning ability (ICO =
1.07) relative to MOR, than Pt/rGO (332 mA/mgPt, ICO = 1.04)
and Pt/C (371 mA/mgPt, ICO = 1.04) catalysts. The improved
performance of Pt/GMC toward the MOR, can be explained by
the small particle size, high dispersion of the nanoparticles of
Pt and the oxygen groups found in the catalyst support due to
its preprocessing functionalization. Moreover, the interaction
between Pt nanoparticles, with graphitized mesoporous carbon
(with a rope-like morphology), promotes free flow of CO2
molecules improving the electrocatalytic activity towards
methanol oxidation [3].
Fig. 3. CV curves of Pt/GMC, Pt/rGO and Pt/C
IV. CONCLUSIONS
The high dispersion of Pt nanoparticles and the oxygenates
groups on GMC, were decisive factors in increasing
electrocatalytic activity of Pt/GMC, also produced a higher
level of CO-tolerance to intermediate carbonaceous species and
higher efficiency to remove them. This study shows that the
electrocatalyst Pt/GMC deserve a deeper analysis on the
development of anodic catalysts for direct methanol fuel cell.
Currently they are applied characterization techniques such as:
Raman spectoscopy, high resolution transmission electron
microscopy, X-ray photoelectron spectroscopy, chronoampero-
metric tests and electrochemical impedance spectroscopy, in
order to make a more complete study of electrocatalysts.
ACKNOWLEDGMENT
This paper has been supported by the National Council for
Science and Technology, México under contract DGEST
4513.12-P; authors also acknowledge the support of
Technological Institute of Ciudad Madero, Technological
Institute of Cancún, Applied Research Center for Advanced
Science and Technology and Research Center for Advanced
Materials.
REFERENCES
[1] J. Hagen, Industrial Catalysis. A Practical Approach, 2nd
ed., WILEY-
VCH Verlag GmbH & Co., 2006, pp. 306-307
[2] F. Ye, Sh. Chen, X. Dong, W. Lin, “Carbon Nanotubes Supported Pt-
Ru-Ni as Methanol Electro-Oxidation Catalyst for Direct Methanol Fuel
Cells,” Journal of Natural Gas Chemistry, vol. 16, pp. 162-166, February
2007.
[3] J. Prabhuram, T.S. Zhao, Z.K. Tang, R. Chen, Z.X. Liang, “Multiwalled
Carbon Nanotube Supported PtRu for the Anode of Direct Methanol
Fuel Cells,” J. Phys. Chem. B, vol. 110, pp. 5245-5252, January 2006 .
[4] H. Zhao, J.P. Dong, S. Xing, Y. Li, J Shen J. Xu, “Electrochemical
Oxidation of Small Organic Molecules on Hydrothermal Synthesized Pt
and PtCo/ordered Mesoporous Carbon,” Int. J. Hydrogen Energy, vol.
36, pp. 9551-9561, June 2011.
[5] Y.-H. Hong, Y.-Ch. Tsai, “Electrodeposition of Platinum and
Ruthenium Nanoparticles in Multiwalled Carbon Nanotube-Nafion
Nanocomposite for ethanol Electrooxidation,” Journal of Nanomaterials,
ID 892178, pp. 1-6, August 2009.
[6] J.-H. Choi, K.-W. Park, I.-S. Park, W.-H. Nam, Y.-E. Sung, “Methanol
Electro-Oxidation and Direct Methanol Fuel Cell Using Pt/Rh and
Pt/Ru/Rh Alloy Catalysts,” Electrochimica Acta, vol. 50 (2-3), pp. 787-
790, October 2004.
[7] F. Su, Ch.K. Poh, J. Zeng, Z. Zhong, Z. Liu, J. Lin, “Pt Nanoparticles
Supported on Mesoporous Carbon Nanocomposites Incorporated with
Ni or Co Nanoparticles for Fuel Cells,” J Power Sources, vol. 205, pp.
136-144, January 2012
[8] J.W. Guo, T.S. Zhao, J. Prabhuram, R. Chen, C.W. Wong,
“Development of PtRu-CeO2/C Anode Electrocatalyst for Direct
Methanol Fuel Cells,” J. Power Sources, vol. 156, pp. 345–354, June
2006.
[9] S.-H. Park, H.-M. Jung, S. Um, Y.W. Song, H.S. Kim, “Rapid Synthesis
of Pt-based Alloy/Carbon Nanotube Catalysts for a Direct Methanol
Fuel Cell using Flash Light Irradiation,” Int. J. Hydrogen Energy, vol.
37, pp. 12597-12604, July 2012.
[10] W. Wei, C. Jieming, Ch. Yu, L. Tianhong, “Preparation of Pt/CMK-3
Anode Catalyst for Methanol Fuel Cells Using Paraformaldehyde as
Reducing Agent,” Chinese Journal of Catalysis, vol. 28(1), pp. 17-21,
January 2007.
[11] J.W. Guo, T.S. Zhao, J. Prabhuram, R. Chen, C.W. Wong, “Preparation
and Characterization of a PtRu/C Nanocatalyst for Direct Methanol Fuel
Cells,” Electrochimica Acta, vol. 51(4), pp. 754-763, September 2005.
[12] L. Xiong, X. Yang, M. Xu, Y. Xu, D. Wu, “Pt–Ni Alloy Nanoparticles
Supported on Multiwalled Carbon Nanotubes for Methanol Oxidation in
Alkaline Media”, J. Solid State Electrochem., vol 17, p. 805, March
2013.
[13] M.A. Abdel-Rahim, R.M. Abdel-Hameed, M.W. Khalil, “The Role of a
Bimetallic Catalyst in Enhancing the Electro-Catalytic Activity Towards
Methanol Oxidation,” J. Power Sources, vol. 135, pp. 42-51, July 2004.
[14] X. Wang, H. Wang, R. Wang, Q. Wang, Z. Lei, “Carbon-supported
Platinum-decorated Nickel Nanoparticles for Enhanced Methanol
Oxidation in Acid Media,” J. Solid State Electrochem., vol. 16, pp.
1049-1054, July 2012.
[15] S. Sharma, B.G. Pollet, “Support Materials for PEMFC and DMFC
Electrocatalysts. A review,” Journal of Power Sources, vol. 208, pp. 96-
119, March 2012
[16] Zh. Lei, L. An, L. Dang, M. Zhao, J. Shi, S. Bai, Y. Cao, “Highly
Dispersed Platinum Supported on Nitrogen-Containing Ordered
Mesoporous Carbon for Methanol Electrochemical Oxidation,”
Microporous and Mesoporous Materials, vol. 119, pp. 30-38, October
2009.
[17] D. Zhao, J. Feng, Q. Huo, N. Melosh, G.H. Fredrickson, B.F. Chmelka,
G.D. Stucky, “Triblock Copolymer Syntheses of Mesoporous Silica with
Periodic 50 to 300 Angstrom Pores,” Science, vol. 279, pp. 548-552,
January 1998.
[18] R. Ryoo, S.H. Joo, S. Jun, “Synthesis of Highly Ordered Carbon
Molecular Sieves via Template-Mediated Structural Transformation,” J.
Phys. Chem. B, vol. 103, pp. 7743-7746, August 1999.
[19] R. Ryoo, S.H. Joo, S. Jun, T. Tsubakiyama, O. Terasaki, “Ordered
Mesoporous Carbon Molecular Sieves by Templated Synthesis: the
Structural Varieties,” Stud. Surf. Sci. Catal., vol. 135, p. 150, September
2007.

5. [20] A. Santasalo-Aarnio, M. Borghei, I.V. Anoshkin, A.G. Nasibulin, E.I.
Kauppinen, V. Ruiz, T. Kallio, “Durability of Different Carbon
Nanomaterial Supports with PtRu Catalyst in A Direct Methanol Fuel
Cell,” Int. J. Hydrogen Energy, vol. 37, pp. 3415-3424, December 2012.
[21] K.-W. Park, K.-S. Ahn, Y.Ch. Nah, J.H. Choi, Y.E. Sung,
“Electrocatalytic Enhancement of Methanol Oxidation at Pt-WOx
Nanophase Electrodes and In-Situ Observation of Hydrogen Spillover
using Electrochromism,” J. Phys. Chem. B, vol. 107, pp. 4352-4355,
April 2003.
[22] M.S. Saha, R. Li, X. Sun, “High Loading and Monodispersed Pt
Nanoparticles on Multiwalled Carbon Nanotubes for High Performance
Proton Exchange Membrane Fuel Cells,” J. Power Sources, vol. 177, pp.
314–322, November 2008.
[23] L. Shahriary, A.A. Athawale, “Graphene Oxide Synthesized by using
Modified Hummers Approach,” Int. J. Renewable Energy and Environ.
Eng., vol. 2, pp. 58-63, January 2014
[24] L. Calvillo, V. Celorrio, R. Moliner, A.B. Garcia, I. Caméan, M.J.
Lazaro, “Comparative study of Pt catalysts supported on different high
conductive carbon materials for methanol and ethanol oxidation,”
Electrochimica Acta, vol. 102, pp. 19-27, April 2013.
[25] J. Park, S. Kim, “Synthesis and electrochemical analysis of Pt-loaded,
polypyrroledecorated, graphene-composite electrodes,” Carbon Letters,
vol. 14, pp. 117-120, February 2013.
[26] F. Ye, X. Cao, L. Yu, S. Chen, W. Lin, “Synthesis and Catalytic
Performance of PtRuMo Nanoparticles Supported on Graphene-Carbon
Nanotubes Nanocomposites for Methanol Electro-Oxidation,” Int. J.
Electrochem. Sci., vol. 7, pp. 1251-1265, February 2012.
[27] Sh. Zhou, H. Xu, Q. Yuan, H. Shen, X. Zhu, Y. Liu, W. Gan, “N-Doped
Ordered Mesoporous Carbon Originated from a Green Biological Dye
for Electrochemical Sensing and High-Pressure CO2 Storage,” ACS
Appl. Mater. Interfaces, vol. 8, pp. 918-926, December 2015
[28] S. Gurunathan, J. Han, J.H. Park, J.H. Kim, “An in vitro evaluation of
graphene oxide reduced by Ganoderma spp. in human breast cancer cells
(MDA-MB-231),” Int. J. Nanomedicine, vol. 9, pp. 1793-1797,
November 2013.
[29] A. Liu, S. Huang, “A glucose biosensor based on direct
electrochemistry of glucose oxidase immobilized onto platinum
nanoparticles modified graphene electrode,” Sci. China Phys. Mech.
Astron., vol. 55, pp. 1163-1167, July 2012.
[30] Z. Wang, G. Shi, F. Zhang, J. Xia, R. Gui, M. Yang, S. Bi, “Amphoteric
surfactant promoted three-dimensional assembly of graphene
micro/nanoclusters to accomodate Pt nanoparticles for methanol
oxidation,” Electrochimica Acta, vol. 160, pp. 288-295, February 2015
[31] Zh. Liu, X. Duan, H. Cheng, J. Zhou, X. Zhou, “Synthesis of
platinum/graphene composites by a polyol method: The role of graphite
oxide precursor surface chemistry,” Carbon, vol. 89, pp. 93-101, March
2015.
[32] R. Zolfaghari, F.-R. Ahmadun, M.R. Othman, W.R.W. Daud, M. Ismail,
“Nonionic surfactant-templated mesoporous carbon as an electrocatalyst
support for methanol oxidation,” Mater. Chem. Phys., vol. 139, pp. 262-
269, January 2013
[33] J.B. Goodenough, A. Hamnett, B.J. Kennedy, R. Manoharan, S.A.
Weeks, “Methanol Oxidation on Unsupported and Carbon Supported Pt
+ Ru Anodes,” J. Electroanal. Chem., vol. 240, pp. 133-145, 1987
[34] M. Watanabe, S. Motoo, “Electrocatalysis by Ad-Atoms: Part III.
Enhancement of the Oxidation of Carbon Monoxide on Platinum by
Ruthenium Ad-Atoms,” J. Electroanal. Chem., vol. 60, pp. 275-283,
1975
[35] Ch.-T. Hsieh, J.-Y. Lin, “Fabrication of Bimetallic Pt–M (M=Fe, Co,
and Ni) Nanoparticle/Carbon Nanotube Electrocatalysts for Direct
Methanol Fuel Cells,” J. Power Sources, vol. 188, pp. 347–352, 2009
[36] A. Hamnett, “Mechanism and Electrocatalysis in the Direct Methanol
Fuel Cell,” Catalysis Today, vol. 38, pp. 445-457, 1997
[37] J.B. Goodenough, R. Mancharan, “Methanol Oxidation in Acid on
Ordered NiTi,” J. Mater. Chem., vol. 2, pp. 875-887, 1992
[38] H. Li, D. Kang, H. Wang, R. Wang, “Carbon-Supported Pt-RuCo
Nanoparticles with Low-NobleMetal Content and Superior Catalysis for
Ethanol Oxidization,” Int. J. Electrochem. Sci., vol. 6, pp. 1058-1065,
2011