Iron selenide nanoparticles coated on carbon nanotubes from single source ferrocene incorporated selenourea precursor for fuel cell and photocatalytic applications

Article abstract of DOI:10.1016/j.jorganchem.2014.07.001

This article presents the synthesis and characterization (multinuclear NMR, FTIR, CHNS, AAS and single crystal XRD) of a single source organometallic precursor namely 1-(4-methylbenzoyl)-3-(3-ferrocenylphenyl)selenourea for the fabrication of iron selenid

Full text of DOI:10.1016/j.jorganchem.2014.07.001

Journal of Organometallic Chemistry 769 (2014) 58e63
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Iron selenide nanoparticles coated on carbon nanotubes from single
source ferrocene incorporated selenourea precursor for fuel cell and
photocatalytic applications
a
a
,
*
a
a
Raja Azadar Hussain , Amin Badshah , Shafiqullah Marwat , Farida Yasmin ,
b
Muhammad Nawaz Tahir
Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad, Pakistan
a
b
Department of Physics, University of Sargodha, Punjab, Pakistan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 April 2014
Received in revised form
This article presents the synthesis and characterization (multinuclear NMR, FTIR, CHNS, AAS and single
crystal XRD) of
a single source organometallic precursor namely 1-(4-methylbenzoyl)-3-(3-
ferrocenylphenyl)selenourea for the fabrication of iron selenide (FeSe) nanoparticles (NPs) supported
on multi walled carbon nanotubes (MWCNTs) which were characterized with XRD, SEM and TEM with
fuel cell and photocatalytic applications.
30 June 2014
Accepted 6 July 2014
Available online 15 July 2014
©
2014 Published by Elsevier B.V.
Keywords:
Ferrocene incorporated selenourea
Photocatalytic degradation
Single crystal
Fuel cell
Introduction
nanotubes (MWCNTs) for fuel cell applications which may resolve
the issue of cost for the acceptance of fuel cells in the open market.
Dying of the paper, textile, ceramics, leather, inks, food stuff and
cosmetics is carried out with the compounds having azo (N]N)
functionality [4]. Almost 15% of these compounds which are pres-
ently in use by the market, enter the environment and have been
reported for their negative effects on the environment and bio-
logical life [5,6]. These compounds are not good in terms of their
biodegradability and are presently being dealt with chemical
methods (chlorination and ozonation) [7] and physical methods
(flocculation, reverse osmosis and adsorption) [8]. Badr et al. have
previously reported the photocatalytic degradation of methyl or-
ange (MO) by gold silver nano-core/silica nano-shell to produce
methyl(phenyl)carbamic acid [9]. Following the same concept we
have carried out the degradation study of MO by FeSe nanoparticles
supported on MWCNTs.
In the recent years FeSe has been synthesized with pulsed laser
deposition [10,11], electrodeposition [12,13], chemical vapor
deposition [14e17], chemical bath deposition [18,19], chemical
vapor transport [20], spray pyrolysis [21], solid state reaction [22],
molecular beam epitaxial growth [23], solid state reaction at
different sintering temperatures [20], thick films from high tem-
perature solution [24] and rapid, solvent-less reaction under
autogenic pressure at elevated temperature (RAPET) [25] etc.
Utilization of fossil fuels for the production of energy is seriously
under consideration for the future of world's economy and ecology.
Use of batteries, fuel cells and electrochemical capacitors is being
aimed over the years for environmental friendly and economical
energy production. Batteries among the three are the ones which
are most successfully applicable in different markets whereas ca-
pacitors are being used mainly in memory devices. Fuel cells
however failed to have their penetration in the market on the basis
of cost, performance and durability. So, the fuel cells which were
being considered as a replacement of combustion engines once are
now in competition with batteries and capacitors. Cost is the most
important and practical factor which hinders the commercializa-
tion of fuel cells [1]. Number of efforts have been made to reduce
the amount of precious metals in the fuel cell by using carbon
supported platinum black, and platinum based bimetallic catalysts
having comparatively cheap metals and Pt/X/Carbon (X ¼ Fe, Ni, Co
and other transition metals) alloyed materials [2,3]. In this article
we have used FeSe nanoparticles coated on multi walled carbon
*
Corresponding author. Tel.: þ92 051 9064 2131.
E-mail address: aminbadshah@yahoo.com (A. Badshah).
http://dx.doi.org/10.1016/j.jorganchem.2014.07.001
022-328X/© 2014 Published by Elsevier B.V.
0

R.A. Hussain et al. / Journal of Organometallic Chemistry 769 (2014) 58e63
59
Different physical parameters and applications of FeSe such as
Table 1
Crystal data of MPT.
photoemission spectrum [26,27], band structure, magnetic
behavior, electronic structure, phonon spectrum, superconducti-
vity, Mossbauer, Raman and XRD spectrum etc. have now been
established. Conventional techniques for the fabrication of nano
materials utilize precursors in different forms and batches but the
use of single source precursor is advantageous because of good
control on stoichiometry, flow, temperature, leak control and
simple installation with safer experimentation [28]. Multiple
source precursors generally utilize the reagents which are oxygen/
MPT
Empirical formula
Formula weight
Temperature (K)
Wavelength Å
a [Å]
25 2
C H22FeN OSe
501.25
296
0.71073
9.9673 (13)
8.5714 (10)
25.616 (2)
90
96.138 (4)
90
2176 (4)
Monoclinic
P-21/c
b [Å]
c [Å]
ꢁ
a
b
g
[ ]
ꢁ
moisture sensitive and toxic i.e. NH
etc. This article deals with the synthesis and characterization
multinuclear NMR, FTIR, CHNS, AAS and single crystal XRD) of a
novel FIS, its conversion to FeSe nanoparticles supported on
MWCNTs and its application as electrode material in H -O fuel cell
29] and as a photocatalyst for biodegradation of MO.
3
, H
2
S, H
2
3
Se, PH , AsH
3
and SiH
4
[ ]
ꢁ
[ ]
3
Volume Å
(
Crystal system
Space group
Z
Density (calculated)
h k l max
4
2
2
1.530 g/cm3
12, 10, 31
[
ꢀ
1
Absorption coefficient (
F(000)
m
)
2.385 mm
1016
1.01
Materials and methods
Goodness-of-fit on F2 (S)
R-Factor (%)
Melting point was determined in a capillary tube using Gallen-
kamp (U.K) electrothermal melting point apparatus. Infrared spec-
trumwas recorded onThermoscientific NICOLET 6700 FTIR between
R
1
¼ 0.04, wR ¼ 0.099
2
ꢀ
1 1
13
4
0
000 and 400 cm . H and C NMR spectra were recorded between
and 13 ppm and 0 and 210 ppm respectively on Jeol JNM-LA 500
acetone. The reaction was monitored with the help of thin layer
chromatography and allowed to proceed for 3 h under constant stir-
ring. Then in the second batch, addition of 0.50 g (0.0018 mol) of meta
ferrocenyl aniline was carried out and the reaction was completed
after further 6 h with 71% yield (Scheme 1). Settled solid product was
then washed with n-hexane and recrystallized in toluene. Decom-
3 4
FT-NMR. Si(CH ) was used as internal reference. The elemental
analysis was performed using a LECO-932 CHNS analyzer while the
Fe concentration was determined on an atomic absorption spec-
trophotometer Perkin Elmer 2380. UV-vis absorption spectra were
recorded on Shimadzu 1800 spectrophotometer between 200 nm
and 800 nm at absorbance of ~1. FeSe/MWCNTs were characterized
ꢁ
positiontemperature 138 C.
H
d (ppm) (Acetone) 13.27 (s,1H),10.47 (s,
1H) 8.19e7.36 (m, 8H), 4.81 (t, J 1.8, 2H), 4.36 (t, J 1.8, 2H), 4.10 (s, 5H),
2.88 (s, 3H). (ppm) (Acetone) 180.6,167.7,144.5,140.4,139.0,129.3,
with CuK
1
a
radiation of 0.154 nm between diffraction angles of
0e80. SEM images were taken on a SEM JEOL model, 5910 LV with
d
C
ꢀ1
128.7, 124.3, 122.3, 121.8, 84.3, 69.5, 69.0, 66.5, 20.9. vmax/cm 3370,
an accelerating voltage of 20 kV at high vacuum (HV) mode and
secondary electron image (SEI). The semi quantification elemental
analysis to find out the weight percentage of the elements was done
using OXFORD INCA energy dispersive X-Ray spectrometer 7274
3229 (b), 3131, 2950, 2928, 1644, 1608, 1521, 1495, 1450, 1375, 1258,
1153, 1071. Anal. Calc. for C25H22N SeFeO: C 59.88, N 5.58, H 4.39, Fe
2
11.17. Found: C 59.87, N 5.58, 4.36, Fe 11.15%.
(
EDS). TEM images were recorded on JEOL 200 CX with a voltage
Synthesis of catalyst
value of 120 kV. Samples were prepared by dispersing them in
methanol followed by sonication for 10 min and then placed on
carbon coated copper grid for analysis.
Cleaning and activation of MWCNTs
Suitable single crystal of MPT was mounted on a glass fiber and
the intensity data were collected on a Brucker kappa APEXII CCD
MWCNTs were sonicated in Branson 1510-DTH sonicator to
separate the nanotubes and clean them from carbon soot. These
MWCNTs were then washed with a 2 N HCl solution for 3 h under
reflux to remove contaminants and activate their surface. In the
diffractometer using graphite-monochromator having Mo K
a ra-
diation (
l
¼ 0.71073 Å) at 296 K. The structures were solved by
2
direct methods and refined by full-matrix least squares against F of
data using SHELXL97 (Sheldrick, 1997) software [30]. Basic crystal
data and description of diffraction experiment are given in Table 1,
whereas selected bond lengths and bond angles have been pre-
sented in Table 2.
next step MWCNTs were oxidized in 5 N HNO solution for 3 h at
3
room temperature and washed with boiling distilled water until
the pH of the rinsed solution reached 6.0. These functionalized
ꢁ
MWCNTs were dried in vacuum oven at 110 C for 4 h.
Ferrocene, metanitro aniline, sodium nitrite, diethyl ether,
acetone, DMSO, Pd-charcoal, 4-methylbenzoyl chloride, and hy-
drazine were purchased from Sigma Aldrich. Meta ferrocenyl ani-
line was synthesized by a procedure reported by our group
previously [18,19,21,31e36].
Synthesis of FeSe/MWCNTs catalyst
20% FeSe/MWCNT's (Fe:Se ¼ 1:1) catalyst was prepared by a
procedure in which MPT and functionalized MWCNTs were
dispersed in acetone by ultra-sonication. Temperature of the son-
ꢁ
icator was kept at 80 C. After complete evaporation of the solvent,
ꢁ
Experimental
the dried carbon powder was heat treated at 650 C in argon
Synthesis of 1-(4-methylbenzoyl)-3-(3-ferrocenylphenyl)selenourea
Table 2
(
MPT)
ꢁ
Selected bond lengths (Å) and angles ( ) for MPT.
ꢁ
Bond type
Distance (Å)
Bond type
Angle ( )
MPT was synthesized in a one pot procedure by the addition of
reactants in two batches inside a two neck round bottom flask under
constant magnetic stirring. In first batch 0.3 g (0.00208 mol) of KSeCN
was reacted with 0.27 mL (0.00208 mol) of 4-methylbenzoyl chloride
to produce yellowish colored solution with a suspension of KCl in
SeeC(17)
OeC(18)
N(1)eH1C
N(2)eH2C
1.819(4)
1.219(4)
0.860(3)
0.861(3)
H(1C)eN(1)eC(15)
H(1C)eN(1)eC(17)
SeeC(17)eN(2)
117.0(3)
117.0(3)
120.2(3)
124.2(3)
SeeC(17)eN(1)

60
R.A. Hussain et al. / Journal of Organometallic Chemistry 769 (2014) 58e63
Scheme 1. Synthesis of 1-(4-methylbenzoyl)-3-(3-ferrocenylphenyl)selenourea.
atmosphere for 2 h [37]. This high temperature results in the
decomposition of the complex and deposition of the iron and se-
lenium in the form of iron selenide on the surface of MWCNTs.
protons i.e. protons of eNH, ferrocene protons, aromatic protons
and methyl protons. Maximum downfield proton is the proton of
eNH (13.27 ppm) which is present between the C]O and C]Se
groups whereas the other eNH appears slightly upfield (10.47 ppm)
from it. Aromatic protons are available at their respective regions as
multiplet and methyl group gives a singlet at 2.88 ppm. Unsub-
stituted cyclopentadienyl ring (Cp ring) of ferrocene yields a singlet
whereas substituted Cp ring provides two triplets downfield from
the singlet of unsubstituted Cp ring with a coupling constant of
Single cell testing
The synthesized 20% FeSe/MWCNTs catalyst was evaluated as
cathode catalyst in H
2 2
-O fuel cell. 30% PtRu/MWCNTs was used as
anode catalyst. 30% Pt/MWCNTs cathode catalysts was used for
ꢀ
2
13
comparison. The metal loading on cathode was kept at 2 mg cm
1.8 Hz. In C NMR maximum downfield carbon is the one which is
ꢀ2
while PtRu loading on anode side was also 2 mg cm . Teflonized
carbon paper (Toray) was used as electrode backing layer for anode
and cathode. Catalyst ink was prepared by sonicating the catalyst in
isopropanol and adding 10% nafion as binder. Catalyst ink was
coated on the electrode by brush in multiple steps until the
attached with selenium (180.6) whereas carbonyl carbon appears
3e4 ppm upfield from it. Aromatic and methyl carbons are visible
in their respective regions whereas unsubstituted Cp ring of
ferrocene gives a singlet while substituted Cp provides three signals
in which maximum downfield carbon is the one which is attached
with the phenyl ring (84.3 ppm) [33e35].
ꢁ
required loading was achieved. After drying the electrodes at 80 C,
ꢀ1
nafion solution (5%) was applied to the electrode surface
In FTIR eNH protons provide a broad signal above 3200 cm
due to the presence of intermolecular and intramolecular hydrogen
ꢀ2
(
3 mg cm ). Membrane electrode assembly was prepared by hot
pressing the anode and cathode with nafion 115 membrane at
bonding. Aromatic protons yield
a stretching band above
ꢁ
ꢀ2
ꢀ1
1
35 C and 60 kg cm . Single cell performance was evaluated in a
3000 cm
and aliphatic protons provide their signal at
ꢁ
ꢀ1
1
laboratory made cell at 25 C. Humidified hydrogen and oxygen
~2900 cm . Carbonyl carbon is available as an intense band at
ꢀ
ꢀ
were used as fuel and oxidant. Hydrogen and oxygen pressure was
kept at 2 atm for anode and cathode respectively.
1644 cm
whereas C]Se is available between 1000 and
1
1300 cm [33e35]. Elemental concentrations, determined with
CHNS analyzer and atomic absorption spectrophotometer, are in
close agreement with calculated values.
Photocatalytic degradation of MO
0
.1 g of FeSe/MWCNTs catalyst was dispersed in 20 mL solution
XRD single crystal structure
of MO in ethanol having absorbance value of ~1. This solution was
placed under UV light of UVGL-58 254/365 nm at short wavelength
mode under constant magnetic stirring in a dark room. The
absorbance of this solution was measured after every 10 min on a
UV-vis spectrophotometer.
Fig. 1 presents the ORTEP diagram of MPT which shows that
protons of ferrocene moiety are not 100% eclipsed (protons are
ꢁ
tilted at an angle of 0.33 only) and phenyl ring attached with Cp of
ꢁ
ferrocene is tilted outside from the plane of Cp at an angle of 26.05 .
Geometric arrangement of groups around C]Se is not symmetric
ꢁ
Results and discussions
i.e. the angle between the Se-C(17)-N(1) is 124.17 whereas the
ꢁ
angle between the Se-C(17)-N(2) is 120.16 . There is an intra-
Characterization of MPT precursor
molecular hydrogen bond between the N(1) and O(1) which forms
a six membered secondary ring. There are four molecules per unit
cell of MPT which are arranged in a way that methyl of each
molecule is emerging out of neighboring axial plane (Fig. 2a)
whereas Fig. 2b represents the interactions in the stacked lattice.
MPT was purified on the basis of its solubility (which is different
from its precursors and byproducts) in common organic solvents. In
1
H NMR spectrum of MPT there are basically four different types of

R.A. Hussain et al. / Journal of Organometallic Chemistry 769 (2014) 58e63
61
image of FeSe/MWCNTs is given in Fig. 4a which shows uniform
shape of the MWCNTs and homogeneous distribution of the FeSe
NPs on them. TEM image presents the formation of FeSe NPs of less
than 10 nm size on MWCNTs (Fig. 4b).
Applications of FeSe/MWCNTs
Fig. 5 shows a plot of absorbance vs. wavelength for photo-
catalytic degradation of MO. Figures of the beakers in the inset
show the color of MO at time zero and after 80 min of treatment
with FeSe/MWCNTs under UV light of 254 nm wavelength. It is
evident from Fig. 5 that the degradation process is slower for first
20 min but after that it is comparatively very fast possibly due to
higher concentration of the hydroxyl radicals formed after 20 min
under UV light [9]. We observed that FeSe/MWCNTs catalyst is
comparatively superior than the previously reported gold silver
nano-core/silica nano-shell and same paper has given the mecha-
nistic formation of methyl(phenyl)carbamic acid by the degrada-
tion of MO [9]. Self organized TiO2 nanotubes (NTs) with Pd
Fig. 1. Molecular diagram of MPT with ellipsoid displacement, non hydrogen atoms
represented by 30% probability boundary spheres and hydrogen atoms are sticks of
arbitrary size.
Characterization of FeSe supported on MWCNTs
2 2
nanoparticles, Fe-doped TiO NTs, Nd-doped TiO NTs, La-doped
Fig. 3a presents the PXRD of FeSe/MWCNTs which has promi-
nent PbO type tetragonal phase. Minor peaks for hexagonal FeSe
are also visible in the pattern [17]. The TGA pattern of MPT (Fig. 3b)
provides a residual mass of 13.07% and if all the MPT is converted to
FeSe then this residual mass should be 26.94%. This difference in
the residual mass is due to the independent thermal evaporation of
ferrocene moiety of MPT because when ferrocene molecule is
subjected to the thermal treatment separately it vaporizes
TiO2 NTs, Pt-doped TiO2 NTs, Cu-doped TiO2 NTs, ZnO/TiO2
coupled oxides, Au-doped TiO2 NTs, TiO /ZnO/Au nanofibers, Ag/
2
AgCl/TiO2 nanoparticles, Fe O /ZnO nanocomposites, different
3 4
morphologies of ZnO (nanorod, nanodisc, porous octahedron) and
Ag-doped ZnO have been previously reported for the degradation
of MO [38,39]. But FeSe/MWCNTs catalyst is comparatively cheaper
and easy to synthesize for industrial use in scrubbers and filters etc.
to control the escape of azo compounds (dyes) into the
environment.
ꢁ
completely at 225 C (red line (in the web version) in Fig. 3b). SEM
Fig. 2. a) Packing of MPT showing intermolecular interactions. b) Stacking in MPT.
Fig. 3. a) Powder XRD of FeSe/MWCNTs, H stands for hexagonal phase of FeSe. b) Comparative TGA of MPT and ferrocene.

62
R.A. Hussain et al. / Journal of Organometallic Chemistry 769 (2014) 58e63
Fig. 4. a) SEM image of FeSe/MWCNTs. b) TEM image of FeSe/MWCNTs.
Table 3
Comparative performance of the two catalysts.
Catalyst
Open circuit
voltage
Current density
Power density
ꢀ
2
ꢀ2
(A cm
)
(W cm
)
3
2
0% Pt/MWCNTs
0% FeSe/MWCNTs
0.975
0.952
0.8
0.6
0.250
0.157
Fig. 6 presents the comparative polarization curves of FeSe/
MWCNTs and Pt/MWCNTs catalysts. The results have been sum-
marized in Table 3 and show inferior performance of FeSe/MWCNTs
in terms of power density, open circuit voltage and current density
relative to Pt/MWCNTs catalyst, but Pt is too much costly as
compared to Fe. We propose that the homogeneously alloyed
blends of FeSe with Pt may improve the performance of FeSe/
MWCNTs and reduce amount of Pt in the cathode and will ulti-
mately reduce the cost [40e43].
Conclusions
We have successfully synthesized and characterized single
source ferrocene incorporated selenourea precursor for the fabri-
cation of FeSe/MWCNTs catalyst which has proved to be a good
photocatalyst for the degradation of methyl orange and may
replace the platinum metal from the electrodes of fuel cell in terms
of its low cost. We have plans in the near future to synthesize the
FeSe/Ni/Co/MWCNTs homogeneously alloyed materials to improve
the performance of FeSe/MWCNTs.
Fig. 5. Photocatalytic degradation of methyl orange by FeSe/MWCNTs with the help of
UV-vis spectroscopy.
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