Chinese Materials Research Society

Progress in Natural Science: Materials International

Progress in Natural Science: Materials International 2012;22(6):616–623

1002-0071 & 2012 Ch

http://dx.doi.org/10.1

nCorresponding au

fax: þ91 44 2257 420

E-mail address:

Peer review unde

Society.

www.elsevier.com/locate/pnsmiwww.sciencedirect.com

ORIGINAL RESEARCH

Platinum-supported mesoporous carbon (Pt/CMK-3) as

anodic catalyst for direct methanol fuel cell applications:

The effect of preparation and deposition methods

Balaiah Kuppan, Parasuraman Selvamn

National Centre for Catalysis Research and Department of Chemistry, Indian Institute of Technology-Madras, Chennai 600 036, India

Received 31 August 2012; accepted 7 October 2012

Dedicated to Professor M.M. Sharma, FRS on the occasion of his 75th birthday.

Available online 9 January 2013

KEYWORDS

Mesoporous carbon;

CMK-3;

Nano-platinum;

Electrocatalyst;

Methanol oxidation;

Fuel cell

inese Materials R

016/j.pnsc.2012.11

thor. Tel.: þ91 44

2.

selvam@iitm.ac.in

r responsibility of

Abstract Platinum-supported ordered mesoporous carbon catalysts were prepared employing

colloidal platinum reduced by four different reducing agents, viz., paraformaldehyde, sodium

borohydride, ethylene glycol and hydrogen, and deposited over ordered mesoporous carbon

(CMK-3) synthesized by silica hard template (SBA-15). The resulting platinum nanoparticles

supported mesoporous carbon, designated as Pt/CMK-3, catalysts were tested for the electocata-

lytic oxidation of methanol. The effect of the various reduction methods on the influence of particle

size vis-�a-vis on the electrocatalytic effect is investigated. All the catalysts were systematically

characterized by XRD, BET and TEM. The results of the synthetic methods, characterization

techniques and the electrocatalytic performance indicate that the Pt/CMK-3 catalysts are superior

to that prepared with activated carbon (Pt/AC) as well as with that of the commercial platinum-

supported carbon catalyst (Pt/E-TEK). In particular, the catalyst, Pt/CMK-3, prepared using

paraformaldehyde reduced platinum showed much higher activity and long-term stability as

compared to the other reducing methods.

& 2012 Chinese Materials Research Society. Production and hosting by Elsevier Ltd. All rights reserved.

esearch Society. Production and ho

.005

2257 4235;

(P. Selvam).

Chinese Materials Research

1. Introduction

Generally, for fuel cell electrode applications, platinum sup-

ported on high surface area carbon is employed [1–3]. The

choice of supports is based on the possibility of high disper-

sion stable metal crystallites with favorable electronic and

geometric properties as well as the interaction of the active

metal and the supports [4,5]. Designing porous carbon

materials as support for electrode application is important

sting by Elsevier Ltd. All rights reserved.

Platinum-supported mesoporous carbon (Pt/CMK-3) as anodic catalyst for direct methanol fuel cell applications 617

for high performance of fuel cell and/or battery technology.

Therefore, careful choice of porous carbon supported catalysts

for facile transport of reactants and products, good electronic

conductivity, high surface reactivity, and ionic conductivity,

would enhance the molecular conversion [6–10]. In this regard,

ordered (meso) porous carbon architecture with high surface

area with tailor-made surface properties, large pore volume

with tunable pore size, and narrow pore size distribution with

interconnected pore network is highly desirable in many

electrochemical applications including fuel cells, lithium ion

batteries, etc. On the other hand, mesostructured carbon

materials synthesized by nanocasting method, viz., manipula-

tion of ordered mesoporous silica templates, are of great

technological interest in many applications encompassing

catalysis and materials science [11–13].

One of the most successful examples of such exploitation is

the synthesis of ordered mesoporous (or nanoporous) carbons

using ordered silica frameworks such as MCM-41, MCM-48,

SBA-51, KIT-6, IITM-56, etc. as templates [14–17]. This

approach is based on a multi-step process via polymerization/

carbonization of carbon precursors diffused within inorganic

matrix followed by removal of the inorganic framework by

leaching so as to replicate the mesoporous structure of the

inorganic templates, viz., silica [2–4]. In this way, several

mesoporous carbons with a variety of porous structures have

been prepared employing sucrose, furfuryl alcohol, etc. as

carbon precursors over ordered silica templates [18–21].

In recent years, mesoporous carbon materials such as

CMK-3 is attracted much attention, which is obtained by

replicating well ordered mesoporous silica, SBA-15. The

obtained mesoporous carbons possess highly ordered 2D

hexagonal structure with excellent textural characteristics

[22–24]. Owing to such exceptional surface properties of these

structured porous carbons, they are used to deposit several

noble metals, in particular platinum and its alloys, and testes

as electrode materials for direct methanol fuel cell (DMFC)

applications [25–27]. However, for an effective and efficient

DMFC usage, a few technological barriers remain to be

overcome before successful commercial applications can be

achieved. One such difficulty is the poisoning of the active

platinum by carbon monoxide, which prevents fuel (methanol)

oxidation [28–30]. One of the possible strategies to overcome

such difficulty is alloying of platinum with oxophilic elements

such as ruthenium, palladium, gold or nickel. In this direction,

considerable effects have been focused, and there appears

to be two possible pathways to explain the improved tolerance

carbon monoxide poisoning [31–34]. Among the various

alloying components, the element ruthenium shows promise

as the platinum–ruthenium alloy follows a bifunctional

mechanistic mode where the adsorbed �OH species, gene-

rated by water dissociation, at the platinum/ruthenium edge

promote the oxidation of carbon monoxide and that ruthe-

nium modifies the electronic structure of neighboring platinum

atoms, thus reducing the affinity for carbon monoxide

species. It is remarkable that the additional element reduces

catalyst poisoning to a significant extent but its incorporation

makes the DMFC is expensive [31–34]. On the other hand,

large discrepancies in the methanol oxidation activities

between well-defined crystal surfaces and electrodes formed

by nanoparticles are not fully understood. It is possible that

non-uniform distributions of platinum atoms in nanoparticles

contribute to the differences. However, the various methods

adopted for the preparation of platinum nanoparticles fol-

lowed by reduction and deposition do not allow good control

over the size and shape, or particle distribution of individual

nanoparticles.

A major component that contributes to the high electro-

catalytic activity 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. The oxidation of the

carbon supports, prior to the catalyst deposition, was found to

increase the electrode activity for room temperature methanol

oxidation [35,36]. The presence of small amount surface

functional groups modifies the chemical and physical proper-

ties of the carbon, improving wettability and accessibility of

methanol to the electroactive surface. In addition, the oxygen

functional groups act as nucleation centers or anchoring sites,

limiting the particle growth, improving the dispersion of

metallic crystallites, and enhancing the stability of the sup-

ported catalysts. At present, there is a lack of understanding

on the role of oxygen groups on the CO tolerance, and this

issue has rarely been investigated. Moreover, heavily oxidized

supports have been avoided because of their low electrical

conductivity [37,38]. The present work is focused on the

reduction of platinum nanoparticles followed by deposition

on mesoporous CMK-3 carbon. The physicochemical and

electrochemical characteristics of the mesoporous carbon

supports and the corresponding platinum supported catalyst,

Pt/CMK-3 were investigated. The influence of the platinum

nanoparticles deposition method and the mesoporous carbon

material properties on the dispersion and size distribution of

platinum nanoparticles on CMK-3 mesoporous carbon has

been discussed. The Pt/CMK-3 electrode catalysts with a

uniform dispersion is comparable to platinum nanoparticles

supported on activated carbon (AC) were achieved. Further-

more, the influence of the electrode fabrication method on the

performance of the Pt/CMK-3 electrode catalyst based fuel

cell was revealed.

2. Experimental section

2.1. Starting materials

All the chemicals used were of analytical grade. Pluronic P123

triblock co-polymer, tetraethoxysilane (99.0%) (TEOS) and

hexachloro platonic acid (99.9%) (H2PtCl6) from sigma Aldrich.

Paraformaldehyde (95.0%), sodium carbonate (99.0%), sodium

borohydride (NaBH4), ethylene glycol, methanol (99.9%),

hydrofluoric acid (48.0%), hydrochloric acid (32.0%) and

sulfuric acid (98.0%) were obtained from Merck.

2.2. Synthesis of SBA-15

Mesoporous silica SBA-15 was prepared by adding tetra-

ethoxysilane (TEOS) into the hydrochloric acid solution of

triblock co-polymer P123. The molar composition was 1: 5.9:

193: 0.017 TEOS/HCl/H2O/P123. The mixture was stirred at

40 1C for 20 h, followed by aging at 100 1C for 48 h. The solid

was filtered and dried at 80 1C overnight. SBA-15 was

obtained by calcinations at 550 1C for 6 h in presence of air

atmosphere [39].

B. Kuppan, P. Selvam618

2.3. Synthesis of CMK-3

Ordered mesoporous carbon CMK-3 was synthesized by

adopting the following procedure [15], before impregnating

sucrose solution the silica template was dried in vacuum at

100 1C for 30 min. the carbon replica were prepared similar to

the procedure reported previously. Typically 1.0 g of SBA-15

mesoporous silica was impregnated with acidic sucrose solu-

tion; the mixture was dried at 100 1C for 6 h and subsequently

at 160 1C for 6 h. the impregnation step was repeated once

again. The obtained dark brown/black sample was carbonized

at 900 1C under nitrogen or argon flow for 6 h with heating

rate of 5 1C min�1. The carbon-silica composite obtained after

pyrolysis was washed with hydrofluoric (HF) acid at room

temperature, to remove the silica template. The template-free

carbon product thus obtained was filtered, washed with

ethanol, and dried at 120 1C. The obtained carbon materials

were designated as CMK-3.

2.4. Preparation of Pt/CMK-3

2.4.1. Paraformaldehyde reduction method

Platinum nanoparticles with 20 wt% loading was supported

on CMK-3 by a Paraformaldehyde reduction method [40]

typically 40 mg carbon and 0.0488 M H2PtCl6.xH2O aqueous

solution were homogenously dispersed in 30 ml water and

ultrasonicated for 30 min. The mixture was heated to 70 1C

while simultaneously string with simultaneous purging N2 to

remove soluble O2. Then 10 ml solution containing Parafor-

maldehyde and sodium carbonate was slowly added dropwise,

and the mixture was stirred for 2.5 h. finally, the sample was

filtered, washed with deionized water, and dried.

2.4.2. Sodium borohydride reduction method

Platinum nanoparticles with 20 wt% loading was supported

on CMK-3 by a wet chemical reduction method [41,42]

typically 40 mg carbon and 0.0488 M H2PtCl6.xH2O aqueous

solution were homogenously dispersed in 30 ml water and

ultrasonicated for 30 min, then this solution was stirred for

1 h. 20 ml of NaBH4 solution was added drop wise to the

carbon suspension with stirring at room temperature. Stirring

was continued for 6 h before the suspension was filtered to

recover the solid product and was washed with large amount

of water. The recovered catalyst was dried at 80 1C for

overnight.

2.4.3. Ethylene glycol reduction method

20 wt% of Pt was loaded on CMK-3 mesoporous carbon

using ethylene glycol reduction method [43,44]. 40 mg of

CMK-3 carbon was dispersed in water and required amount

of hexachloroplatinic acid was added to the above solution.

30 ml of ethylene glycol (EG) were added under vigorous

stirring. The solution was refluxed at 140 1C for 4 h. After

reaction, the obtained products were filtered, washed with

water and ethanol, and then dried.

2.4.4. Hydrogen reduction method

The dispersion of platinum electrocatalyst was carried out by

adopting a required amount of hexachloroplatinic acid to the

mesoporous carbon synthesized followed by evaporation to

dryness at 80 1C and reduction in H2 at 350 1C for 3 h [45].

2.5. Characterization

Powder X-ray diffraction (XRD) measurements were carried

out on a Rigaku Miniflex II desktop model advanced powder

X-ray diffractometer with a Cu Ka (l¼1.5405 A) radiation

source, operating at 30 kV and 15 mA. Wide and small angles

were obtained at scanning rate of 31 min�1 and 0.51 min�1,

respectively. Transition electron microscope (TEM) images

were obtained with JEOL 3010 UHR TEM equipped with a

Gatan Imaging Filter. Prior to observation, carbon sample

was sonicated in absolute ethanol for 10 min and then

dropped on to a carbon film supported on a copper grid.

Nitrogen adsorption-desorption isotherms were obtained at

77 K on a Micrometrics ASAP 2020 apparatus. The specific

surface area of the samples were calculated according to the

Brunaur–Emmet–Teller (BET) method, and pore size distribu-

tion curves were obtained from the analysis of nitrogen

adsorption isotherms using Barrett–Joyner–Halenda (BJH)

method. Hydrogen chemisorption measurements for the sup-

ported catalysts were performed on a Micrometrics ASAP

2020 system.

2.6. Electrochemical studies

The performance of Pt supported on CMK-3 mesoporous

carbons, activated carbon and E-TEK commercial catalyst for

room temperature electro oxidation reaction was evaluated by

cyclic voltammetry (CV) using a BAS 100 electrochemical

analyzer. A conventional three-electrode cell consisting of the

glassy carbon (GC, 0.07 cm2) working electrode, Pt wire as

counter electrode and SCE reference electrode were used for

the cyclic voltammetry studies. The catalyst ink was prepared

by ultrasonically dispersing 5.0 mg catalyst in 0.50 ml water

and the working electrode was prepared by casting 10 ml into a

GC disk electrode with 3.0 mm diameter. The CV experiments

were performed using 1 M H2SO4 solution in the absence and

presence of 1 M CH3OH at a scan rate of 25 mV s�1. All the

solutions were prepared by using double distilled pure water.

3. Results and discussion

Fig. 1 depicts the low-angle XRD patterns of ordered

mesoporous silica (SBA-15), carbon (CMK-3) and platinum

supported carbon (Pt/CMK-3). It can be seen from this figure

that all the materials show well resolved reflections character-

istic of 2D- hexagonal lattice having MCM-41-type structure.

In particular, the diffraction pattern of CMK-3 indicates that

the mesoporous carbon is replicated the parent structure of

SBA-15 with a reduce unit cell constant (Table 1). Fig. 2

shows the wide-angle XRD patterns of platinum nanoparticles

supported mesoporous carbon by different deposition meth-

ods. The diffraction patterns represent all the reflections

corresponding to face centered cubic lattice of platinum

supported on mesoporous carbon. The computed values the

crystallite size of the platinum nanoparticles are listed in

Table 2. It is clear from Fig. 1 and Table 2 that the

paraformaldehyde reduction method gives raise to relatively

smaller particle size while the hydrogen reduction method

yield much larger particle platinum particles which is in good

agreement with the literature [46,47]. Figs. 3 and 4 illustrate

the nitrogen-sorption isotherms of SBA-15 and CMK-3,

Platinum-supported mesoporous carbon (Pt/CMK-3) as anodic catalyst for direct methanol fuel cell applications 619

respectively. These isotherms conform the uniform mesopores

typical of type-IV isotherms which exhibit H1 hysteresis loop

with a capillary condensation at relative pressure (P/P0)

0.45–0.9, however, with a difference in micropores which

could be accounted for the broadness of hysteresis loops

[15,48].

Figs. 5 and 6 present the TEM images of SBA-15 and

CMK-3. The figures indicate well ordered hexagonal symme-

try and that the mesoporous carbon represents exactly an

inverse replica of parent mesoporous silica with a calculated

pore diameter of �4.0 and 6.5 nm, respectively. This observa-

tion in good agreement with the values obtained from nitrogen

sorption data (see also Table 1). Shown in Figs. 7–10 are the

TEM images, SEAD, and particle size distribution of platinum

nanoparticles supported mesoporous carbon prepared by

various methods. It is clear from these images that the

paraformaldehyde reduced platinum depicts fine dispersion

on CMK-3 with a narrow size distribution in the range,

4–5 nm (Fig. 7). Whereas the sodium borohydride (Fig. 8)

and ethylene glycol (Fig. 9) reduction methods give �6–7 nm

particle sizes with a similar size distribution. On the other

hand, as expected, hydrogen reduction method gives much

large particle size (�18–20 nm; Fig. 10). Further, TEM

(Fig. 11) of a representative sample, i.e., 10 wt% Pt/CMK-3

preparted by paraformaldehyde reduction method clearly

depicts that the platinum nanoparticles (�4 nm) are well

1 2 3 4 5 6 7

200100

100

Inte

nsi

ty (

a.u.)

2θ (deg.)

Fig. 1 Low-angle XRD patterns of: (a) SBA-15, (b) CMK-3 and

(c) 20 wt% Pt/CMK-3.

Table 1 Structural and textural properties of mesoporous silica

Material Lattice constant, a0 (nm) Surface area, SBET (m

SBA-15 10.4 720

CMK-3 9.6 997

distributed within the mesopores of the framework structure

CMK-3. The calculated platinum nanoparticles sizes from

TEM images are in excellent with the computed values from

XRD (see also Table 2). Thus, it is evident that a narrow

particle size distribution of �4–5 nm is achieved in the

paraformaldehyde reduction method, and therefore if forms

one the most preferable method over other reduction methods

for the preparation of uniform and smaller platinum clusters.

The electrocatalytic properties of the various Pt/CMK-3

catalysts towards the methanol oxidation reactions were

tested. To investigate the electrocatalytic activity of the

prepared Pt/CMK-3 electrocatalysts, room temperature CV

measurements of the methanol oxidation reaction were carried

out in 1 M H2SO4 and 1 M CH3OH aqueous solution at

potential scan rate of 25 mVs�1 (Fig. 12). The forward anodic

peak, If around 0.7-0.8 V versus SCE, is due to the oxidation

methanol. In the backward scan, Ib the oxidation peak around

0.5–0.6 V versus SCE is attributed to the oxidation of COads

like species, generated via incomplete oxidation of methanol

during the forward scan. The If value relates directly to the

methanol oxidation activity of the electrocatalysts. Among the

prepared electrocatalysts, the paraformaldehyde reduction

method gives better activity over the other methods. The ratio

of the anodic peak current densities in the forward and reverse

scans could give another measure of its catalytic perfor-

mances. That is, a higher If/Ib ratio indicate superior oxidation

activity of methanol during the anodic scan and less accumu-

lation of carbonaceous species on the nanocatalyst surface,

and thus shows better CO tolerance [49,50]. On the other

hand, the entire Pt/CMK-3 catalysts show higher If/Ib ratio

than commercial platinum supported carbon catalysts, for

example, the commercial Pt/E-TEK catalyst shows a much

lower ratio (0.72). The higher electrocatalytic activity of the

and carbon.

2g�1) Pore volume, Vp (cm3g�1) Pore size, D (nm)

1.1 6.5

1.3 4.0

20 30 40 50 60 70 80 90

22231

1

22020

0111

Inte

nsity

(a.

u.)

2 (deg.)

Fig. 2 Wide-angle XRD patterns of 20 wt% Pt/CMK-3 prepared

with different reduction methods loadings.

Table 2 Microtructural and electrochemical data of various Pt/CMK-3 electrocatalysts.

Catalysta Reduction method Crystallite size, Pt EAS (m2g�1) Onset

potential (V)

Current, I at 0.7 V

(mA (mg.Pt) �1)

Activity

loss (%)

If/Ib

XRD (nm) TEM (nm)

Pt/CMK-3 Paraformaldehyde 4.3 4.5 84 0.14 185 65 1.33

Pt/CMK-3 Sodium Borohydride 6.0 6.0 78 0.14 157 58 1.57

Pt/CMK-3 Ethylene Glycol 5.5 6.0 72 0.16 165 95 0.76

Pt/CMK-3 Hydrogen 18.0 20.0 70 0.11 105 92 1.55

a20 wt% Platinum supported mesoporous carbon.

0.0 0.2 0.4 0.6 0.8 1.00

200

400

600

P/P0

Qua

ntity

Ads

orbe

d (c

m³/

gST

P)

SBA-15

5 10 15 200

5

10

15

20

Pore

Vol

ume

(cm

³/g)

D (nm)

Fig. 3 N2 sorption isotherms of SBA-15. The inset shows pore

size distribution of SBA-15.

0.0 0.2 0.4 0.6 0.8 1.00

250

500

750

1000

P/P0

Qua

ntity

Ads

orbe

d (c

m³/

gST

P)

CMK-3

Fig. 4 N2 sorption isotherms of CMK-3. The inset shows pore

size distribution of CMK-3.

Fig. 5 TEM image of SBA15. The inset shows SAED pattern of

SBA-15.

Fig. 6 TEM image of CMK-3. The inset shows SAED pattern of

CMK-3.

B. Kuppan, P. Selvam620

former is due high dispersion of uniform sized platinum

nanoparticles on the mesoporous carbon support [29,49,51].

In practical cases, highly dispersed Pt catalysts with large

surface areas are extremely important to increase the electro-

catalytic activity. The large EAS is due to the fact that Pt

nanoparticles are smaller and more uniformly dispersed on the

surfaces of CMK-3 prepared by paraformaldehyde reduction

method. Moreover, it is also well known that smaller catalyst

particles show higher electrochemical active surface area

(EAS), see also Table 2. Furthermore, Pt nanoparticles

dispersed on CMK-3 allows uniform dispersion of the Pt

nanoparticles, thereby producing much more accessible Pt

sites for efficient catalytic activity.

In addition, it is also important to address the long time

stability of the electrocatalysts for application view point.

In this regard, the stability of all the Pt/CMK-3 catalysts

were tested by chronoamperometric measurement studies at

the corresponding forward peak potential (0.7 V) for 3 h in

Fig. 7 TEM image of 20 wt% Pt/CMK-3, Inset: SAED pattern

of mesoporous carbon 20 wt% Pt/CMK-3 and particle size

distribution of 20Pt/CMK-3 by paraformaldehyde reduction

method.

Fig. 8 TEM image of 20 wt% Pt/CMK-3, Inset: SAED pattern

of mesoporous carbon 20 wt% Pt/CMK-3 and particle size

distribution of 20 wt% Pt/CMK-3 by sodium borohydride reduc-

tion method.

Fig. 9 TEM image of 20 wt% Pt/CMK-3, Inset: SAED pattern

of mesoporous carbon 20 wt% Pt/CMK-3 and particle size

distribution of 20 wt% Pt/CMK-3 by ethylene glycol reduction

method.

Fig. 10 TEM image of 20 wt% Pt/CMK-3, Inset: SAED pattern

of mesoporous carbon 20 wt% Pt/CMK-3 and particle size

distribution of 20 wt% Pt/CMK-3 by hydrogen reduction

method.

Platinum-supported mesoporous carbon (Pt/CMK-3) as anodic catalyst for direct methanol fuel cell applications 621

1 M H2SO4 and 1 M CH3OH. The results are presented as

inset in Fig. 11. It can be seen from this figure that all the

electrodes display an initial fast current decay followed by

slower attenuation upon long time operation, reaching a

quasi-equilibrium steady state. This initial fast decay is

attributed to the formation of intermediate species such as

COads, CH3OHads, and CHOads during electrochemical

methanol oxidation reaction. The slow attenuation at longer

times may be due to the adsorption of sulfate anions on the

electrocatalyst surface. The lower stability of some of the

catalyst can be attributed partly due to larger and/or

agglomerated platinum nanoparticles. However, the long

term stability of the Pt/CMK-3, in general, is consistent

with the view that the high dispersion of platinum nano-

particles on the high surface area mesoporous carbons

provides much better dispersion of metal nanoparticles

and better utilization and therefore accelerates the rate of

COads oxidation.

4. Conclusion

In a summary, platinum nanoparticles deposited over meso-

porous CMK-3 carbon by paraformaldehyde reduction

method is superior than the other reduction methods

employed in this study, viz., sodium borohydride, ethylene

glycol and hydrogen reduction methods. Furthermore, the

paraformaldyde method is more suitable for the preparation

of the high dispersed uniform seized platinum nanoparticles

on the mesorporous support with an average particle size of

�4 nm. Thus, the dispersion and particle size distribution of

plkatinum nanoparticles on CMK-3 is strongly dependent on

both the deposition method and the carbon support properties.

Fig. 11 TEM image of 10%Pt/CMK-3 by paraformaldehyde

reduction method.

-0.2 0.0 0.2 0.4 0.6 0.8 1.0

0

100

200

300

E(V) vs SCE, sat.KCl

Cur

rent

den

sity

(m

A/m

g Pt

)

Paraformaldehyde

Ethylene Glycol

Sodium borohydride

Hydrogen

Fig. 12 CVs of 20 wt% Pt/CMK-3 recorded in mixture of 1 M

H2SO4 and 1 M CH3OH with a scan rate of 25 mV at 25 1C. Inset:

Corresponding chronoamperometric curves.

B. Kuppan, P. Selvam622

On the other hand, the performance of the Pt/CMK-3 catalysts

exhibit higher activity and better stability than commercial

platinum supported carbon catalysts. The enhanced activity is

of the platinum supported mesoporous carbon is attributed to

better dispersion and utilization of the platinum, which essen-

tially originate from a higher surface area, large pore volume and

narrow pore size distribution of thee mesoporous carbon

materials. Thus the present study demonstrates that optimized

reduction methods and appropriate choice of carbon supports

can offer significant cost savings by lowering the catalyst loading.

Acknowledgment

Thank are due to the Department of Science and Technology,

New Delhi for funding NCCR, IIT-Madras. This work is

partially supported by a grant-in-aid for the Scientific

Research by the Ministry of New and Renewable Energy

under Grant no. 103/140/2008-NT. The authors thank Pro-

fessor B. Viswanathan for fruitful discussion.

References

[1] H. Liu, C. Song, L. Zhang, J. Zhang, H. Wang, D.P. Wilkinson,

A review of anode catalysis in the direct methanol fuel cell,

Journal of Power Sources 155 (2006) 95–110.

[2] S.H. Joo, S.J. Choi, I. Oh, J. Kwak, Z. Liu, O. Terasaki,

R. Ryoo, Ordered nanoporous arrays of carbon supporting high

dispersions of platinum nanoparticles, Nature 412 (2001) 169–172.

[3] J.-S. Yu, S. Kang, S.B. Yoon, G. Chai, Fabrication of ordered

uniform porous carbon networks and their application to a

catalyst supporter, Journal of the American Chemical Society

124 (2002) 9382–9383.

[4] J. Lee, S. Yoon, S.M. Oh, C.-H. Shin, T. Hyeon, Development of

a new mesoporous carbon using an HMS aluminosilicate tem-

plate, Advanced Materials 12 (2000) 359–362.

[5] H. Zhou, S. Zhu, M. Hibino, I. Honma, Electrochemical

capacitance of self-ordered mesoporous carbon, Journal of Power

Sources 122 (2003) 219–223.

[6] V.A. Paganin, E.A. Ticianelli, E.R. Gonzalez, Development and

electrochemical studies of gas diffusion electrodes for polymer

electrolyte fuel cells, Journal of Applied Electrochemistry 26

(1996) 297–304.

[7] Z. Qi, A. Kaufman, Low Pt loading high performance cathodes

for PEM fuel cells, Journal of Power Sources 113 (2003) 37–43.

[8] B. Viswanathan, Architecture of carbon support for Pt anodes in

direct methanol fuel cells, Catalysis Today 141 (2009) 52–55.

[9] H. Zhou, S. Zhu, M. Hibino, I. Honma, M. Ichihara, Lithium

storage in ordered mesoporous carbon (CMK-3) with high

reversible specific energy capacity and good cycling performance,

Advanced Materials 15 (2003) 2107–2111.

[10] T. Hyeon, S. Han, Y.-E. Sung, K.-W. Park, Y.-W. Kim, High-

performance direct methanol fuel cell electrodes using solid-

phase-synthesized carbon nanocoils, Angewandte Chemie, Inter-

national Edition 42 (2003) 4352–4356.

[11] A. Corma, From microporous to mesoporous molecular sieve

materials and their use in catalysis, Chemical Reviews 97 (1997)

2373–2419.

[12] M. Hartmann, G. Chandrasekar, A. Vinu, Adsorption of Vitamin E

on Mesoporous Carbon Molecular Sieves, Chemistry of Materials

17 (2005) 829–833.

[13] J. Roggenbuck, M. Tiemann, Ordered mesoporous magnesium

oxide with high thermal stability synthesized by exotemplating

using CMK-3 carbon, Journal of the American Chemical Society

127 (2005) 1096–1097.

[14] R. Ryoo, S.H. Joo, M. Kruk, M. Jaroniec, Ordered mesoporous

carbons, Advanced Materials 13 (2001) 677–681.

[15] S. Jun, S.H. Joo, R. Ryoo, M. Kruk, M. Jaroniec, Z. Liu,

T. Ohsuna, O. Terasaki, Synthesis of new, nanoporous carbon

with hexagonally ordered mesostructure, Journal of the American

Chemical Society 122 (2000) 10712–10713.

[16] Y. Wan, D. Zhao, On the controllable soft-templating

approach to mesoporous silicates, Chemical Reviews 107 (2007)

2821–2860.

[17] P. Selvam, S.K. Bhatia, C.G. Sonwane, Recent advances in

processing and characterization of periodic mesoporous MCM-41

silicate molecular sieves, Industrial and Engineering Chemistry

Research 40 (2001) 3237–3261.

[18] P. Selvam, K.N. Vamshi, B. Viswanathan, Architecting mesopor-

ous AlSBA-15: An overview on the synthetic strategy, Journal of

the Indian Institute of Science 90 (2010) 271–285.

Platinum-supported mesoporous carbon (Pt/CMK-3) as anodic catalyst for direct methanol fuel cell applications 623

[19] P. Selvam, P.R. Murthy, K.N. Vamshi, B. Viswanathan, in:

Proceedings of the 3rd International Conference on Advanced

Materials and Systems (ICAMS-2010) (210).

[20] C.T. Kresge, M.E. Leonowicz, W.J. Roth, J.C. Vartuli, J.S. Beck,

Ordered mesoporous molecular sieves synthesized by a liquid–

crystal template mechanism, Nature 359 (1992) 710–712.

[21] S.E. Dapurkar, S.K. Badamali, P. Selvam, Nanosized metal

oxides in the mesopores of MCM-41 and MCM-48 silicates,

Catalysis Today 68 (2001) 63–68.

[22] D. Zhao, J. Feng, Q. Huo, N. Melosh, G.H. Frederickson,

B.F. Chmelka, G.D. Stucky, Triblock copolymer syntheses of

mesoporous silica with periodic 50 to 300 angstrom pores, Science

279 (1998) 548–552.

[23] C. Yu, J. Fan, B. Tian, D. Zhao, G.D. Stucky, High-yield synthesis

of periodic mesoporous silica rods and their replication to meso-

porous carbon rods, Advanced Materials 14 (2002) 1742–1745.

[24] P. Selvam, K.N. Vamshi, B. Viswanathan, in: Proceedings of the

3rd International Conference on Advanced Materials and Sys-

tems (ICAMS-2010) (2010).

[25] J. Ding, K.-Y. Chan, J. Ren, F.-s. Xiao, Platinum and platinum–

ruthenium nanoparticles supported on ordered mesoporous

carbon and their electrocatalytic performance for fuel cell reac-

tions, Electrochimica Acta 50 (2005) 3131–3141.

[26] F. Su, J. Zeng, X. Bao, Y. Yu, J.Y. Lee, X.S. Zhao, Preparation

and characterization of highly ordered graphitic mesoporous

carbon as a Pt catalyst support for direct methanol fuel cells,

Chemistry of Materials 17 (2005) 3960–3967.

[27] M.-L. Lin, C.-C. Huang, M.-Y. Lo, C.-Y. Mou, Well-ordered

mesoporous carbon thin film with perpendicular channels: appli-

cation to direct methanol fuel cell, Journal of Physical Chemistry

C 112 (2008) 867–873.

[28] J. Kua, W.A. Goddard III, Oxidation of methanol on 2nd and

3rd row group VIII transition metals (Pt, Ir, Os, Pd, Rh, and Ru):

Application to direct methanol fuel cells, Journal of the American

Chemical Society 121 (1999) 10928–10941.

[29] Z. Liu, X.Y. Ling, X. Su, J.Y. Lee, Carbon-supported pt and ptru

nanoparticles as catalysts for a direct methanol fuel cell, Journal

of Physical Chemistry B 108 (2004) 8234–8240.

[30] C. Xu, L. Wang, R. Wang, K. Wang, Y. Zhang, F. Tian, Y.

Ding, Nanotubular mesoporous bimetallic nanostructures with

enhanced electrocatalytic performance, Advanced Materials 21

(2009) 2165–2169.

[31] O.T.M. Musthafa, S. Sampath, High performance platinized

titanium nitride catalyst for methanol oxidation, Chemical Com-

munications (2008) 67–69.

[32] Z.-B. Wang, P.-J. Zuo, G.-P. Yin, Investigations of compositions

and performance of PtRuMo/C ternary catalysts for methanol

electrooxidation, Fuel Cells 9 (2009) 106–113.

[33] A.N. Haner, P.N. Ross, Electrochemical oxidation of methanol

on tin-modified platinum single-crystal surfaces, Journal of

Physical Chemistry 95 (1991) 3740–3746.

[34] K.-W. Park, J.-H. Choi, B.-K. Kwon, S.-A. Lee, Y.-E. Sung,

H.-Y. Ha, S.-A. Hong, H. Kim, A. Wieckowski, Chemical and

electronic effects of Ni in Pt/Ni and Pt/Ru/Ni alloy nanoparticles

in methanol electrooxidation, Journal of Physical Chemistry B

106 (2002) 1869–1877.

[35] X. Li, W.-X. Chen, J. Zhao, W. Xing, Z.-D. Xu, Microwave

polyol synthesis of Pt/CNTs catalysts: Effects of pH on particle

size and electrocatalytic activity for methanol electrooxidization,

Carbon 43 (2005) 2168–2174.

[36] J.M. Sieben, M.M.E. Duarte, C.E. Mayer, Electro-oxidation of

methanol on Pt–Ru nanostructured catalysts electrodeposited

onto electroactivated carbon fiber materials, ChemCatChem. 2

(2010) 182–189.

[37] S. Sharma, A. Ganguly, P. Papakonstantinou, X. Miao, M. Li,

J.L. Hutchison, M. Delichatsios, S. Ukleja, Rapid microwave

synthesis of CO tolerant reduced graphene oxide-supported

platinum electrocatalysts for oxidation of methanol, Journal of

Physical Chemistry C 114 (2010) 19459–19466.

[38] L. Li, Y. Xing, Pt–Ru nanoparticles supported on carbon

nanotubes as methanol fuel cell catalysts, Journal of Physical

Chemistry C 111 (2007) 2803–2808.

[39] D. Zhao, J. Feng, Q. Huo, N. Melosh, G.H. Frederickson,

B.F. Chmelka, G.D. Stucky, Triblock copolymer syntheses of

mesoporous silica with periodic 50–300 angstrom pores, Science

279 (1998) 548–552.

[40] W. Wu, J. Cao, Y. Chen, T. Lu, Preparation of Pt/CMK-3

anode catalyst for methanol fuel cells using paraformaldehyde

as reducing agent, Chinese Journal of Catalysis 28 (2007)

17–21.

[41] D. Geng, G. Lu, Dependence of onset potential for methanol

electrocatalytic oxidation on steric location of active center in

multicomponent electrocatalysts, Journal of Physical Chemistry

C 111 (2007) 11897–11902.

[42] J. Zeng, J.Y. Lee, Effects of preparation conditions on perfor-

mance of carbon-supported nanosize Pt–Co catalysts for metha-

nol electro-oxidation under acidic conditions, Journal of Power

Sources 140 (2005) 268–273.

[43] Z. Lei, S. Bai, Y. Xiao, L. Dang, L. An, G. Zhang, Q. Xu, CMK-5

Mesoporous carbon synthesized via chemical vapor deposition of

ferrocene as catalyst support for methanol oxidation, Journal of

Physical Chemistry C 112 (2008) 722–731.

[44] Z. 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 119 (2009) 30–38.

[45] V. Raghuveer, A. Manthiram, Mesoporous carbons with con-

trolled porosity as an electrocatalytic support for methanol

oxidation, Journal of the Electrochemical Society 152 (2005)

A1504–A1510.

[46] A. Pozio, M. De Francesco, A. Cemmi, F. Cardellini, L. Giorgi,

Comparison of high surface Pt/C catalysts by cyclic voltammetry,

Journal of Power Sources 105 (2002) 13–19.

[47] E. Antolini, F. Cardellini, Formation of carbon supported Pt–Ru

alloys: an XRD analysis, Journal of Alloys and Compounds 315

(2001) 118–122.

[48] A. Vinu, K. Ariga, T. Mori, T. Nakanishi, S. Hishita, D. Golberg,

Y. Bando, Preparation and characterization of well-ordered hex-

agonal mesoporous carbon nitride, Advanced Materials 17 (2005)

1648–1652.

[49] Y. Mu, H. Liang, J. Hu, L. Jiang, L. Wan, Controllable Pt

nanoparticle deposition on carbon nanotubes as an anode

catalyst for direct methanol fuel cells, journal of Physical

Chemistry B 109 (2005) 22212–22216.

[50] B. Kuppan, B. Viswanathan, P. Selvam, Platinum-supported

ordered mesoporous carbon (Pt/CMK-n; NCCR-n) as electro-

catalyst for direct methanol fuel cell applications, in: Proceedings

of the 15th National Workshop on ‘‘The Role of New Materials

in Catalysis’’. Dec. 11–13, 2011, Chennai, 2011, pp. 93.

[51] M.-L. Lin, M.-Y. Lo, C.-Y. Mou, PtRu nanoparticles supported

on ozone-treated mesoporous carbon thin film as highly active

anode materials for direct methanol fuel cells, Journal of Physical

Chemistry C 113 (2009) 16158–16168.