Enhanced catalytic actIVity and near room temperature gas sensing properties of SnO2 nanoclusters@mesoporous Sn(IV) organophosphonate composite

Article abstract of DOI:10.1039/c7dt01939d

A simple, facile and one-pot route for preparing SnO₂ nanoclusters embedded on a mesoporous Sn(iv) organophosphonate (MSnP) framework is described. Reaction of SnCl₄·5H₂O with a flexible tris-phosphonic acid, mesityl-1,3,5-tris(methylenephosphonic acid), in the presence of a surfactant under hydrothermal conditions produced the desired nanocomposite, SnO₂@MSnP. Analytical, spectroscopic and microscopic studies establish that SnO₂@MSnP composite is comprised of SnO₂ nanoparticles of an average size of 5 nm evenly and abundantly dispersed over the MSnP framework. The mesoporous metal organophosphonate support significantly augments the catalytic efficacy and vapor sensitivity of SnO₂ nanoparticles. The catalytic efficiency of SnO₂@MSnP was tested for two acid-catalyzed reactions: deoximation reaction and esterification of fatty acids. SnO₂@MSnP exhibits remarkable sensitivity towards ammonia and acetone vapors at near room temperature and under open atmospheric conditions. The present method represents an important step towards preparation of mesoporous metal organophosphonate supported metal oxide nanoclusters and hence offers easy access to functional metal oxide based nanocomposites.

Full text of DOI:10.1039/c7dt01939d

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Bhattacharyya, J. Deka, A. Borah, A. Devi, D. Deka, S. Mishra, K. Raidongia and N. Gogoi, Dalton Trans.,
2017, DOI: 10.1039/C7DT01939D.
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ISSN 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
rsc.li/dalton

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ARTICLE
Enhanced catalytic activity and near room temperature gas
sensing properties of SnO2 nanoclusters@mesoporous Sn(IV)
organophosphonate composite
Suchibrata Borah,a Bagmita Bhattacharyya,‡a Jumi Deka,‡b Aditya Borah,a Anuchaya Devi,c
Dhanapati Deka,c Shashank Mishra,d Kalyan Raidongia,b and Nayanmoni Gogoi*,a
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
(Dedicated to Prof. Mihir K. Chaudhuri on the occasion of his 70th birthday)
A
simple, facile and one pot route for preparing SnO2 nanoclusters embedded on
a
mesoporous
Sn(IV)organophosphonate(MSnP) framework is described. Reaction of SnCl4.5H2O with a flexible tris-phosphonic acid,
mesityl-1,3,5-tris(methylenephosphonic acid) in presence of a surfactant under hydrothermal conditions produced the
desired nanocomposite, SnO2@MSnP. Analytical, spectroscopic and microscopic studies establish that SnO2@MSnP
composite is comprised of SnO2 nanoparticles of an average size of 5 nm evenly and abundantly dispersed over the
mesoporous Sn(IV) organophosphonate framework. The mesoporous metal organophosphonate support significantly
augments the catalytic efficacy and vapor sensitivity of SnO2 nanoparticles. The catalytic efficiency of SnO2@MSnP was
tested for two acid catalyzed reactions viz. deoximation reaction and esterification of fatty acids. SnO2@MSnP exhibits
remarkable sensitivity towards ammonia and acetone vapors at near room temperature and under open atmospheric
conditions. The present method represents an important step towards preparation of mesoporous metal
organophosphonate supported metal oxide nanoclusters and hence offers an easy access to functional metal oxide based
nanocomposite.
rational and predetermined fashion.4 For example,
mesoporous MCM-41 supported SnO2 nanoparticles show five
times enhancement of H2 sensing capability as compared to
Introduction
Metal oxide based nanostructures display
a fascinating
the pristine SnO2 based gas sensor.5
assortment of intriguing characteristics and this catapulted an
outburst of their applications in diverse domains e.g. medicine,
information technology, catalysis, energy storage, sensing, etc.
Aluminosilicate based mesoporous materials have proliferated
as one of the most appealing class of support for fabricating
nanocomposites due to their robustness.6 However, the
inherent difficulties in functionalization of aluminosilicate
based materials limit their potential as support systems with
tunable characteristics. In view of this, metal organic
frameworks (MOFs) have emerged as versatile porous support
material for fabricating functional metal oxide based
nanocomposites.7 By using appropriately functionalized
organic linker for constructing MOFs, it is possible to tailor the
physicochemical characteristics of the voids and thus modulate
interaction between metal oxide-MOF supports. Traditionally,
carboxylate based linkers decorated with desired functionality
has remained the most preferred choice of linker due to the
high surface area, uniform pore size distribution and high
crystallinity of the resulting MOFs.8 Indeed, several carboxylate
based MOF supported metal oxide/metallic nanocomposites
have been developed and they display enhanced
characteristics as compared to pristine metal oxide/metallic
nanoparticles.7 For example, encapsulation of SnO2
nanoclusters inside the pores of MIL-101(Cr) significantly
improved the performance of the composite as anode material
1
In this context, tailoring physicochemical characteristics of
metal oxide based nanostructures for specific applications has
emerged as one of the most desirable and fundamental
challenge in contemporary nanotechnology.2
Since, most characteristics of metal oxide based
nanostructures are intimately linked with their structure,
morphology and size, a great deal of interest has been devoted
for controlling these parameters.3 Apart from the above,
surface functionalization of metal oxide based nanostructures
by confining inside the voids of porous materials has emerged
as another appealing route to modulate their properties in a
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in Li-ion battery due to the confinement of pulverized metal phosphonate composite material. Further, the reaction
particles.9 However, carboxylate based MOFs are susceptible was carried out in presence of a surfactant to facilitate the
to hydrolysis in presence of water due to the weak nature of formation of SnO2 nanoparticles and also to impart
metal-carboxylate linkages and this has remained as one of the mesoporous character to the hybrid phosphonate framework.
most pressing challenges for their eventual applications in
industry.10
Results and discussion
Organophosphonates form considerably strong metal-oxygen
bonds with high valent metal ions and it accounts for the
Synthesis and characterization of SnO2@MSnP
The reaction of mesityl-1,3,5-tris(methylenephosphonic acid)19
astounding stability and poor crystallinity displayed by
organophosphonate based metal organic frameworks.11 Most
with an excess of SnCl4.5H2O in presence of cetyltrimethyl
importantly, the inherent stability of organophosphonate
ammonium bromide (CTAB) under hydrothermal condition
based MOFs allow post-synthetic functionalization while
produced SnO2 impregnated Sn(IV) phosphonate, SnO2@MSnP
retaining their original structures. For example, sulphonation
(Figure 1). SnCl4.5H2O is hydrolytically unstable and therefore,
on aryl substituents of zirconium phenyl phosphonate can be
excess SnCl4.5H2O present in the reaction mixture produces
carried out by using fuming sulphuric acid under harsh
SnO2 nanoparticles under hydrothermal conditions in presence
reaction conditions, while the integrity of the framework is
of the surfactant.
completely retained.12 The acid resistance capability of high
FT-IR spectrum of SnO2@MSnP displays an intense absorption
at 1051 cm-1 which is characteristic for Sn-O-P stretching
valent metal organophosphonate frameworks also allows
assembling periodic mesoporous structures by surfactant
vibrations (Figure S1). Absence of any peak in the range 2850-
template synthesis of phosphonate framework.13 One of the
most appealing characteristic of such mesoporous metal
organophosphonate frameworks is their ability to act as
adsorbent for metal ions.14 In principle, the adsorbed metal
ions can be subsequently calcined to result homogeneously
dispersed metal oxide nanoclusters over the mesoporous
metal organophosphonate frameworks.15 It is pertinent to
note here that in spite of the boundless possibilities for
functionalization, metal organophosphonate supported metal
oxide nanocomposites are scarce.16 This can be mainly
attributed to the relatively poor thermal robustness of the
organophosphonate based frameworks which do not allow
preparation of metal oxide nanoclusters by calcination at
temperatures above ~300 °C. Moreover, integrity of thermally
unstable functional groups present on the phosphonate
framework may get lost during calcination and this severely
limits the scope of hybrid framework supports. Thus, synthetic
strategies resulting nanocomposites, where metal oxide
nanoclusters are embedded onto metal organophosphonate
frameworks is a highly desirable yet immensely challenging
goal for engineering nanoscale devices with improved
performance. In particular, fabrication of SnO2 based
nanocomposite is a highly meaningful task in view of their
widespread utility in diverse applications e.g. gas sensors, Li-
ion battery, solar cells, catalysis, etc.17
2930 cm-1 confirms the near complete removal of surfactant
CTAB used for preparation of the mesophase. Further, absence
of any signal near 2300 cm-1 indicates the deprotonation of all
P-OH groups of the phosphonate ligands present in
SnO2@MSnP. The broad and strong absorption band observed
at 632 cm-1 can be assigned to the antisymmetric Sn-O-Sn
vibrational mode of SnO2.
Thermogravimetric decomposition pattern of SnO2@MSnP
shows that between the temperature range 33-105 °C, 9.8 %
weight loss occurs and this can be attributed to the loss of
occluded water molecules present on the surface of the
mesoporous material (Figure S2). Another sharp weight loss of
10.9 % observed within the temperature range 300-460 °C
occurs due to the loss of organic substituents present on the
phosphonate ligand in SnO2@MSnP. On heating above 460 °C,
the weight loss continues at a uniform but slower rate as the
decomposition of the organic substituents proceeds until upto
700 °C.
Small angle powder XRD spectrum (Figure S3) of SnO2@MSnP
shows no peak possibly due to the disordered arrangement of
the mesoporous material. Further, presence of heavy metal
ion such as Sn(IV) with higher X-ray absorption cross-section
also reduce the probability of X-ray diffraction at smaller
incidence angles. However, wide angle powder X-ray
diffraction pattern of SnO2@MSnP depicted in Figure 2 shows
five intense and broad peaks centered at 2θ values of 26.4°,
33.9°, 38.3°, 51.6° and 65.3°. The observed X- ray diffraction
pattern can be readily indexed to the tetragonal rutile phase of
Herein, a one pot synthetic pathway to fabricate a hybrid
composite material where in situ generated SnO2
nanoparticles are embedded on
a mesoporous Sn(IV)
phosphonate support has been developed. It is well
established that SnCl4 undergoes facile reaction with
organophosphonic
acid
and
several
Sn(IV)
organophosphonates have been reported so far.18 A tris-
phosphonic acid with flexible phosphonate groups have been
chosen for building the hybrid Sn(IV) phosphonate framework
due to the possibility of enhanced interlinking of individual
metal phosphonate layers which will result in a robust and
dense framework. An excess of hydrolytically unstable metallic Figure 1: Synthesis of mesoporous MSnP supported SnO2 nanoclusters.
precursor was used to ensure formation of a metal oxide-
2 | J. Name., 2012, 00, 1-3
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The textural properties of SnO2@MSnP were investigated by
using N2 adsorption/desorption isotherm method at 77 K. As
depicted in Figure 4, a type IV N2 adsorption/desorption
isotherm with an H1 hysteresis loop typical of mesoporous
materials is observed.22 The BJH pore size distribution profile
of SnO2@MSnP shows unimodal distribution of pores with
mean size 4.2 nm and thereby establishes the mesoporous
nature of the composite (Figure S5). Further, BET surface area
analysis showed that SnO2@MSnP has a surface area of 267 m2
g-1 (Figure S6).
Further, in order to compare properties of SnO2 nanoparticles
with and without the presence MSnP host, pristine SnO2
nanoparticles were precipitated from an aqueous solution of
reported procedure.23 SnO2
Figure 2: Powder X-ray diffraction pattern of SnO2@MSnP along with reference
powder X-ray diffraction pattern of SnO2 rutile phase.
SnCl4.5H2O following
a
nanoparticles were characterized under electron microscopy
and N2 adsorption/desorption isotherms at 77 K. The BET
surface area of pristine SnO2 nanoparticles was measured to
be 236 m2g-1 (Figure S7). The representative TEM images in
Figure S8, suggest that the average size of the pristine SnO2
nanoparticles (≈ 4 - 7 nm) are in the same range with that of
SnO2@MSnP samples. The diffuse reflectance UV-visible
spectrum of SnO2@MSnP is also in good agreement with that
obtained for pristine SnO2 nanoparticles and the calculated
band gap is 3.5 eV (Figure S9). The SnO2@MSnP
nanocomposite also shows photoluminescence behavior
typical of pristine SnO2 nanoparticles and shown in Figure S10.
The oxidation states of the elements present in SnO2@MSnP
were determined with XPS analysis. Two sharp intense peaks
observed at 488.2 eV and 495.5 eV are characteristic of two
electronic states 3d5/2 and 3d3/2 respectively, in Sn4+ (Figure
S11). XPS spectra of SnO2@MSnP also show one peak for P 2p
at binding energy 133.5 eV and this confirms that phosphorous
is present in pentavalent state (Figure S12). The broad C 1s
peak can be fitted with two components situated at binding
energies 284.6 & 286.3 eV and they can be attributed to C
species of C-H, C-C or C-P present in SnO2@MSnP (Figure S13).
The influence of embedded SnO2 nanoparticles on the
chemical environment of the constituents in the hybrid
nanocomposite was probed by solid-state 13C, 31P and 119Sn
MAS NMR spectroscopy. The 13C CP MAS NMR of SnO2@MSnP
shows four distinct peaks at 136, 128, 29 and 18 ppm
SnO2 (JCPDS card no. 88-0287) and peaks at 2θ values of 26.4°,
33.9°, 38.3°, 51.6°and 65.3° can be assigned to miller indices
110, 101, 200, 211 and 301 respectively.20 The broad nature of
peaks observed in the X-ray diffraction pattern of SnO2@MSnP
indicates small particle size of the SnO2 nanoclusters present in
the sample. From the Scherrer equation of average particle
size determination by using the width of peaks at half maxima,
the average particle size of SnO2 nanoparticles present in
SnO2@MSnP was found to be 5.4 nm.21
The surface morphology of SnO2@MSnP was examined under
electron microscopes. Scanning electron microscope (SEM)
image depicted in Figure 3a reveals the microscopic
morphology of the powder sample, which is comprised of
particles with different sizes and shapes. The particles
appeared to be crystalline with sharp edges and smooth
surfaces are embraced with uniformly dispersed nanoparticles
as confirmed by the transmission electron microscopy (TEM)
examinations, see Figure 3b and 3c. The average diameter of
nanoparticles lie within 4-6 nm range, which is in a good
agreement with the particle size calculated from X-ray
diffraction pattern. The particles embedded on MSnP matrix
were confirmed to be SnO2 by analyzing HRTEM images, as
shown in Figure 3d where the lattice fringes of particles are
assigned to (110) plane of SnO2 with interlayer spacing’s of
0.33 nm. Moreover, the EDX analysis showed well-resolved
signals for Sn, O, C and P, which is consistent with the
suggested chemical formulation of SnO2@MSnP (Figure S4).
Figure 3: (a) SEM, (b) and (c) TEM images of SnO2@MSnP. (d) HRTEM images of
SnO2 nanoparticles embedded on MSnP matrix.
Figure 4: N2 adsorption/desorption isotherm SnO2@MSnP at 77 K.
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Table 1: Result of deoximation reactions.
indicating the presence of four different types of carbon in the
material (Figure S14). The peaks at 136 and 128 ppm can be
attributed to the two types of aromatic carbon atoms while
the peaks at chemical shift 29 and 18 ppm can be assigned to
the CH2 and CH3 carbon atoms of the phosphonate ligand
respectively. Moreover, 31P MAS NMR spectrum of
SnO2@MSnP shows only one peak at 16.5 ppm and it clearly
indicates that only 111 type of bonding of the phosphonate
ligand is present while no free P-OH or P=O groups are present
in the framework (Figure S15). This observation is also
supported by IR data where no band for free P-OH or P=O are
observed. Thus, each phosphonate ligand is coordinated to
three Sn centers and a -P-(O-Sn)3- type of linkage is prevalent
in the framework. 119Sn CP MAS NMR spectrum of
SnO2@MSnP shows a distinct peak at -604 ppm flanked by two
spinning sidebands at -533 and -676 ppm which are
characteristics of pristine SnO2 with an octahedral
coordination environment around Sn4+ (Figure S16). Apart from
the above, another peak at chemical shift -772 ppm is also
observed in the 119Sn MAS NMR spectra of SnO2@MSnP and
this can be attributed to phosphonate bridged Sn(IV) atom.
O
O
O
O
O
OH
1c (71 %)
1a (99 %)
1b (96 %)
NO2
Cl
1e (70 %)
O
O
O
1d (80 %)
O
OH
O
N
O
CH3
1f (67 %)
OH
1g (97 %)
1h (89 %)
1i (60 %)
1j (0 %)
Further, entry 1i in Table 1 shows that deoximation reaction of
aliphatic dioxime selectively yielded the mono-oxime
derivative, while the monooxime itself did not undergo
deoximation even when the reaction was extended for 24
hour. This can be attributed to the mild acidic character of the
catalyst SnO2@MSnP, which is not effective to catalyze
deoximation of unactivated aliphatic monooximes. It is
pertinent to note here that the monodeoximated product,
diacetylmonooxime is an important pathological reagent for
determination of urea in biological samples and therefore its
selective preparation is a highly desirable goal.25 Moreover,
the recyclability of nanocomposite as catalyst in deoximation
reaction was investigated and significant quenching of the
catalytic activity was observed after the first run itself. Further,
as compared to conventional reagents used for oxidative
deoximation reaction, the time required for obtaining
satisfactory conversion by SnO2@MSnP is considerably long.24
Nevertheless, the ability to categorically improve the acid
catalytic activity of SnO2 nanoclusters by dispersing over
hybrid Sn(IV) organophosphonate framework demonstrate the
synergistic effect present between the phosphonate support
and SnO2 nanoclusters. Thus, in principle designing
heterogeneous catalytic systems with high selectivity and
efficiency is possible simply by variation of the organic
substituents present on the phosphonate moiety.
Catalytic behavior of SnO2@MSnP
The catalytic efficacy of SnO2@MSnP in acid promoted
reactions was initially investigated by using the acid catalyzed
deoximation of aldoximes and ketoximes as the model
reaction (Scheme 1). Cleavage of oximes into their parent
carbonyl compounds is a highly desirable synthetic goal and a
large number of methods for deoximation reaction have been
so far developed.24
Results of SnO2@MSnP catalyzed deoximation reaction for
different substrates are listed in Table 1. SnO2@MSnP showed
very good catalytic activity with up to 99% conversion in
deoximation reaction of aldoximes and ketoximes under
optimized reaction conditions. However, identical reactions in
the absence of any catalyst or in presence of pristine SnO2
showed relatively poor conversion of the oximes. Further, the
catalytic efficacy of Sn(IV) phenyl phosphonate in the
deoximation reaction under similar reaction conditions
showed only 5% conversion. Moreover, almost quantitative
conversions of oximes were observed when the free
phosphonic acid or SnCl4 was as used as catalyst. However,
these can be primarily attributed to the Bronsted acidic nature
of the free phosphonic acid and release of HCl due to
hydrolytic cleavage of SnCl4 under the reaction conditions.
Thus, the enhanced catalytic efficacy of SnO2@MSnP in the
deoximation reaction can be easily attributed to the synergistic
effect between the mesoporous Sn(IV) organophosphonate
support and SnO2 nanoclusters embedded upon it.
Esterification of long chain free fatty acid (FFA) is an important
step during biodiesel production from vegetable oil feedstock
and a plethora of catalyst including porous solid acid catalysts
has been reported for the esterification of FFA.26 However,
most of these processes involve harsh reaction conditions and
environmentally detrimental solvents. It is pertinent to note
here that sulphated SnO2 act as an efficient catalyst in
esterification of FFA.27 In view of the improved catalytic
efficacy of the hybrid nanocomposite, SnO2@MSnP in
deoximation reaction, its catalytic activity in esterification
reaction of FFA in waste vegetable oil was also investigated.
The FFA esterification reaction was carried out by using waste
edible oil collected from restaurants inside the Tezpur
University campus, Assam, India. The FFA conversion rate (a
relative scale) was used to analyze the completion of
esterification reaction. In order to proceed for alkali-catalyzed
transesterification reaction, the target acid value suggested is
less than 2 mg KOH/g. Therefore, the FFA conversion rate of
HO
O
N
Acetone:Water;1:1
Reflux, 6-9 h
SnO2@MSnP (10 wt%)
R1
R2
R1
R2
Scheme 1: Deoximation of aldoximes/ketoximes using SnO2@MSnP catalyst.
4 | J. Name., 2012, 00, 1-3
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Figure 5: The reduction FFA content in the oil sample with time in presence of
SnO2@MSnP & SnO2 as catalyst in esterification reaction.
Figure 6: Current-Voltage characteristics of SnO2@MSnP device in the presence
and absence of (a) ammonia, (c) acetone. Response curves of SnO2@MSnP and
SnO2 nanoparticle devices are compared at different concentrations of (b)
ammonia and (d) acetone at 50 °C.
80% was set as a cut-off point to evaluate the effectiveness of
the catalyst for esterification reaction, i.e. whether the end
product had reached less than 1% FFA and was suitable for the
subsequent alkali-catalyzed transesterification. The initial FFA
content of the used cooking oil was found to be 7.21 mg
KOH/g at 0 min, and with time the FFA content at 60 min, 120
min and 180 min was recorded by titration as 4.61, 2.11 and
0.82 mg KOH/g, respectively. The FFA conversion efficiency of
SnO2@MSnP has been recorded as 89% when the reaction was
carried out at 60 °C for 3 hour. However, pristine SnO2
nanoparticles show only 43% FFA conversion under identical
reaction condition (Figure 5). The improved efficiency in ester
hydrolysis by SnO2@MSnP as compared to pristine SnO2
nanoparticles can be attributed to synergistic effect between
the SnO2 nanoclusters and the phosphonate framework.
Therefore, the SnO2@MSnP catalyst is a potential candidate
for esterification reaction in biodiesel synthesis process from
vegetable oil and efforts are currently underway to design
SnO2@Sn-organophosphonate framework with better catalytic
activity.
shown at Figure 6a distinctively reveal that conductivity of the
samples increases in presence of ammonia.
The real time response curve of the SnO2@MSnP device
towards four different concentrations of NH3 vapor is
compared to
a
similar device prepared from SnO2
nanoparticles (Figure 6b). It is clearly seen that SnO2
nanoparticles embedded on MSnP exhibits higher sensitivity
towards trace amounts of ammonia vapors as compared to
that of pristine nanoparticle. Moreover, SnO2@MSnP device
exhibits better response (35 s) and recovery time (180 s) as
compared to that of pristine nanoparticles, which were
calculated to be 70 and 220 s, for an average of 10
measurements, respectively. The SnO2@MSnP device was also
found to be sensitive towards acetone vapors and typical I-V
curves of acetone sensing experiments are shown at Figure 6c.
The real-time response curve in Figure 6d compare the sensing
performance of SnO2@MSnP with that of pristine SnO2
nanoparticles at four different concentrations of acetone. At
each concentration, SnO2@MSnP shows higher sensitivity
along with better response speed as compared to that of
pristine SnO2 nanoparticle device. However, SnO2@MSnP
device exhibits poor recovery time (80 s) as compared to the
pristine SnO2 device with average recovery time of 35 s. In
order to test the stability of SnO2@MSnP devices during vapor
sensing experiments, multiple cycles of sensing was performed
in case of ammonia. Indeed, no deterioration of the response
% was observed even up to 100th cycle of ammonia sensing
and it clearly indicates the reusability of the device (Figure
S39a and S39b). Moreover, IR-spectrum (Figure S39c) and
powder X-ray diffraction pattern (Figure S39d) of SnO2@MSnP
recorded after 100 cycles of ammonia sensing also did not
show any reasonable deviation from those obtained in case of
the fresh sample and thereby confirms the chemical
robustness of the SnO2@MSnP device during vapor sensing
experiments. The sensing capabilities of SnO2@MSnP were
also tested for other chemical vapors such as nitrobenzene
and ethanol, but the electrical resistance of SnO2@MSnP was
unaffected by those vapors (Figure S40). The sensing
Vapor sensing properties of SnO2@MSnP
The ever-increasing environmental pollutions instigated an
intense search for new materials capable of sensing toxic
chemicals in trace amounts. Among the various materials
tested for creating next generation solid state sensing devices,
nanomaterials of SnO2 are considered to be most promising.28
However, most of the SnO2 based devices works at high
temperature (above 200 °C) and inert atmosphere.29 Here, we
have demonstrated the sensitivity of SnO2@MSnP towards
ammonia and acetone vapors at 50 °C and under open
atmospheric conditions. Sensing devices were fabricated by
placing the powder samples mixed with a 5% solution of
polytetrafluoroethylene between two Cu electrodes. As
prepared devices were mounted in an open glass container
and resistance between the electrodes were measured using a
source meter instrument (see Supporting Figure S38).
Appropriate amount of vapors were introduced into the glass
chamber, by injecting respective liquids through a syringe. The
current versus voltage (I-V) curves of SnO2@MSnP device
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mechanism of reducing gas such as acetone, NH3 by SnO2 synergy between the MSnP support and SnO2 particles one can
nanoparticles are attributed to release of surface electrons easily tailor the characteristics of the present device. Judicious
captured by atmospheric oxygen molecules.30,31 It is functionalization of the organic phosphonate ligand used for
anticipated that the mesoporous metal phosphonate support, the preparation of the nanocomposite can act as a versatile
MSnP matrix augment rate of ionization of atmospheric tool to modulate its selectivity as well as efficiency in different
oxygen molecules to oxygen ions over its surface as compared sensing applications.
to pristine nanoparticles. Therefore, when the sensor was
exposed to the gas molecules, the surface oxygen ions react
Conclusions
with them and release the trapped electrons back into the
conduction band of SnO2 resulting enhancement in electrical
conductivity.
A new nanocomposite bearing SnO2 nanoparticles of average
size 5.4 nm embedded onto a mesoporous organic-inorganic
hybrid material has been synthesized under hydrothermal
condition. The one pot synthetic technique involved
simultaneous production of SnO2 nanoparticles and a hybrid
mesoporous Sn(IV) phosphonate framework which acted as a
versatile support for the SnO2 nanoclusters. The resultant
nanocomposite, SnO2@MSnP has been utilized as efficient
catalyst in deoximation of aldoximes/ketoximes and
esterification of FFA in waste vegetable oil. Due to the synergy
between the SnO2 nanoparticles and the mesoporous Sn(IV)
phosphonate matrix, the catalytic efficacy of the
nanocomposite in both the acid promoted reactions are
significantly augmented as compared to pristine nanoparticles.
The synergetic effect was further supported by the
enhancement of SnO2 sensitivity towards NH3 and acetone
vapors at near room temperature and open atmospheric
conditions. More importantly, the present methodology to
prepare metal oxide@mesoporous metal phosphonate
nanocomposite can be virtually extended for all high-valent
metallic ions by employing hydrolytically unstable precursors.
Further, hybrid metal phosphonate based frameworks are
easily accessible and there is an abundance of possibilities to
incorporate a wide range of functional groups onto these
frameworks. Therefore, the present approach for in situ
generation of metal oxide-metal phosphonate nanocomposite
offers a unique and fascinating pathway to modify the
physicochemical characteristic of nanocomposites by using
appropriately functionalized metal phosphonate support. We
are currently investigating these possibilities.
The responsiveness of SnO2@MSnP sample towards NH3 and
acetone vapors are also compared with recent literature
reporting SnO2 based sensors on the Table 2 and Table 3.30,31
Apart from the ability to sense both NH3 and acetone vapors at
relatively low temperature, the present nanocomposite
displays reasonably efficient response towards both the gases
under investigation. Thus, the vapor sensing experiments
provided additional evidence towards synergetic effects
between the MSnP framework and SnO2 nanoparticles
embedded over it. Although, the performance of the
SnO2@MSnP device in sensing acetone or ammonia vapors are
not reasonably superior as compared to state of the art
sensors reported earlier, it is anticipated that by exploiting the
Table 2: NH3 sensing performances of SnO2 based gas sensors prepared by various
synthetic methods.
Sl.
No
1
Material
Operating
Temperature
Room
temperature
350 °C
Response
Reference
RGO-SnO2
Ig/Ia = 1.12 for 1%
NH3
30
30
nanocomposite
Carbon nanoflakes-
SnO2 composite
Polypyrrole-SnO2
nanocomposite
SnO2 nanowires
2
3
4
5
6
7
(Ig/Ia) = 72% for
100 ppm of NH3
(Rg/Ra) = 27% for
100 ppm of NH3
(Rg/Ra) = 36% for
40 ppm of NH3
(Ra/Rg) ≈ 2 for 100
ppm NH3
(Ig/Ia) ≈ 2.5 for
500 pm NH3
(Ra-Rg/Ra)×100 ≈
90 % for 128 ppm
NH3
Room
Temperature
400 °C
30
30
Al-doped SnO2
nanobelt
SnO2−SnS2 hybrid
350 °C
30
Room
temperature
50 °C
30
SnO2@MSnP
This work
Table 3: Acetone sensing performances of SnO2 based gas sensors prepared by various
synthetic methods.
Experimental
Sl.
No
1
Material
Operating
Temperature
400 °C
Response
Reference
Materials
Pt-decorated SnO2
fibers
SnO2 Hollow
Microspheres
Pd-loaded SnO2
nanofibers
SnO2 nanoparticles
loaded on
graphene
(Ra/Rg-1) = 6.5 for 3
ppm acetone
(Ra/Rg) = 16 for 50
ppm acetone
(Ra/Rg) = 24 for 20
ppm acetone
(Ra/Rg) = 169.7 for
200 ppm acetone
31
31
31
31
All the chemicals were purchased from different sources and
used as received without any further purification. Solvents
were also purchased from commercial sources and were
distilled prior to use, using common purification techniques.
Mesityl-1,3,5-tris(methylenephosphonic acid) was synthesized
following a reported procedure.32
2
3
4
200 °C
275 °C
350 °C
5
6
SnO2-MWCNT
nanocomposites
SnO2 nanofibres
functionalised with
RGO
200-350 °C
350 °C
80 % for 1 ppm
acetone
(Ra/Rg)= 10 at 5 ppm
of acetone
31
31
Synthesis of SnO2@MSnP
An amount of 1.093 g CTAB (3.0 mmol) was dissolved in 5 mL
H2O and stirred for
2 h. Then, 0.321 g mesityl-1,3,5-
7
SnO2@MSnP
50 °C
(Ra-Rg/Ra)×100 ≈ 88
% 140 ppm of
acetone
This work
tris(methylenephosphonic acid)(0.8 mmol) in 3 mL H2O was
added to the CTAB solution and stirred for 12 hour. To this
solution was added 1.051 g of SnCl4∙5H2O (3.0 mmol) dissolved
6 | J. Name., 2012, 00, 1-3
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in 4 mL H2O. Soon after the addition of Sn(IV) chloride a cream Vapor sensing by SnO2@MSnP
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DOI: 10.1039/C7DT01939D
ARTICLE
colored precipitate was observed. The whole mixture was The sensing device of SnO2@MSnP and SnO2 nanoparticles
stirred for another 12 h and finally transferred and sealed in a were fabricated by making films of the samples by mixing with
stainless steel autoclave for hydrothermal treatment at 403 K 5% solution of polytetrafluoroethylene in water between two
for 3 days. After cooling, the product was filtered and washed Cu electrodes separated by 3 mm apart. As prepared sensors
several times with distilled water. To remove the surfactant, were mounted on an open glass container placed on a hot
0.5 g of the as-synthesized material was extracted 3 times with plate maintained at 100 °C. The temperature around sensing
20 ml of acidified ethanol in each batch and then with pure device was recorded to be 50 °C. Sensors were exposed to
ethanol to remove the remaining acid. The extracted material various concentrations of ammonia and acetone vapors by
was dried in vacuum. FT-IR (KBr, cm-1): ῡ = 3410 (br), 1629 (m), injecting appropriate amount of ammonium hydroxide and
1456 (w), 1051 (s), 632 (s), 515 (s); TGA (10 °C/minute, under acetone into the glass container using
a syringe. The
N2atmosphere): Temperature Range °C(weight loss): 33-105 concentration of the vapors was calculated assuming all the
(9.8%); 300-460 (10.9%).
vapor molecules remains inside the open container during the
measurements. The response behavior of the sensors was
studied by measuring the change in resistance between the
SnO2@MSnP catalyzed deoximation reaction
The deoximation reaction was carried out by using different two electrodes by using a Keithley source meter instrument,
oximes in presence of SnO2@MSnP. At first acetophenone model 2450. The response of the sensors were calculated by
oxime was taken as substrate to find the optimum reaction the formula,
condition. The catalytic activity of SnO2@MSnP was compared
ꢀꢁꢂꢃꢄꢅꢂꢁ % = (ꢀꢆ − ꢀꢇ)/ꢀꢆ × 100,
with SnO2 and it was found that our catalyst shows more where Ra and Rg are the resistance in the absence and
efficiency than SnO2. Table S1 and table S2 includes the presence of the vapors, respectively.
optimization reactions and Table S3 includes all the reactions
with different aliphatic and aromatic substrates.
Characterization
In a typical reaction, 1 mmol of oxime was placed in a round All the chemicals were purchased from different sources and
bottomed flask and dissolved in acetone-water (1:1) mixture. used as received without any further purification. Solvents
Catalyst SnO2@MSnP was added to it and refluxed for 7 hours. were also purchased from commercial sources and were
The progress of the reaction was monitored by TLC. After distilled prior to use, using common purification techniques.
completion, the product extracted and collected with ethyl Mesityl-1,3,5-tris(methylenephosphonic acid) was synthesized
acetate. Yield was calculated by GC-MS. The oximes were following a reported procedure.32 Perkin Elmer Frontier MIR-
synthesized using standard procedures.33
FIR FT-IR spectrophotometer was used to obtain Fourier
transformed infrared spectra from 400 to 4000 cm-1. NMR
Esterification reaction of waste cooking oil using SnO2@MSnP spectra were recorded on
as a catalyst spectrometer operating at 400 MHz and samples were
The esterification reaction was performed in a three-neck dissolved in deuterated solvents. Chemical shifts are reported
round bottom flask. One neck was facilitated with in parts per million downfield of Me4Si (TMS) as internal
a JEOL JNM-ECS400 NMR
a
thermometer to measure the constant temperature. A water standard. Elemental analyses were performed on a Perkin
cooled condenser was equipped to another neck on top of the Elmer Model PR 2400 Series II Elemental Analyzer. Thermo-
reactor to reduce evaporative loss of methanol. The third neck gravimetric analyses were performed on a Shimadzu TGA-50
was utilized for chemical addition and taking samples. The thermal analyzer. Melting point was recorded on a Buchi M-
reactor was placed in a water bath and heated on a hot plate. 560 melting point apparatus. The scanning electron
Methanol and SnO2@MSnP was mixed before the reaction and microscopy (SEM) analyses were carried out using a JEOL JSM-
oil were heated to the desired temperature before the 6390LV SEM, equipped with an Energy-Dispersive X-ray
addition of methanol and SnO2@MSnP mixture. The methanol analyzer. The powder X-ray diffraction patterns were recorded
and oil are immiscible so the agitating speed was kept at 600 on a Bruker AXS D8 Focus X-ray diffractometer instrument
revolutions per minute (rpm) to ensure efficient mixing34 for using a nickel-filtered CuKα (0.15418 nm) radiation source and
each run, 2 wt% of SnO2@MSnP and 6:1 molar ratio of scintillation counter detector. Solid state 13C, 31P and 119Sn
methanol to used cooking oil was used. Oil was added into the NMR spectra were recorded on
a AVANCE III 500WB
flask and heated to the desired temperature. 2 mL aliquot of spectrometer using adamantane (38 ppm), H3PO4 (0 ppm) and
sample was withdrawn from the flask for titration at 0, 60,120 SnO2 (-604.3 ppm) as references, respectively. X-Ray
and 180 minute intervals after the onset of the reaction. The photoelectron spectroscopy (XPS) analysis was carried out on a
titration of FFA followed AOCS Cd 3d-63, which is a standard KRATOS Axis Ultra DLD electron spectrometer using an Al Kα
method for FFA titration in oil.35 Esterification of used cooking (1486.6 eV) radiation source. GC-MS was recorded on a Perkin
oil has been confirmed by 1H-NMR spectroscopy and Elmer Clarus 600 C Mass Spectrometer. The pore structures
compared with the literature.36
were explained by a FEI TECNAI G2 20 S-TWIN transmission
electron microscope operated at an accelerating voltage of
200 kV. Nitrogen adsorption/desorption isotherms were
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Journal Name
13 J. E. Haskouri, C. Guillem, J. Latorre, A. Beltŕan, D. Beltŕan
and P. Amoŕos, Chem. Mater., 2004, 16, 4359; J. E. Haskouri,
C. Guillem, J. Latorre, A. Beltŕan, D. Beltŕan and P. Amoŕos,
Eur. J. Inorg. Chem., 2004, 1804; T. Kimura, Chem. Mater.,
2003, 15, 3742; T. Kimura, Chem. Mater., 2005, 17, 337; T.
Kimura, Chem. Mater., 2005, 17, 5521; T. Y. Ma and Z. Y.
Yuan, Chem. Commun., 2010, 46, 2325.
14 T. -Y. Ma, X. -J. Zhang and Z. -Y. Yuan, J. Phys. Chem. C, 2009,
113, 12854; X. -J. Zhang, T. -Y. Ma and Z. -Y. Yuan, Chem.
Lett.,2008, 37, 746.
obtained by a Quantachrome NOVA 1000E surface area
analyzer.
Acknowledgements
Generous financial supports from SERB-DST (Grant No.
EMR/2016/002178) and CSIR, New Delhi (Grant No.
01(2789)/14/EMR-II) are gratefully acknowledged. KR
acknowledge Ramanujan Research Grant (SB/S2/RJN- 15 X. -Y. Hao, Y. -Q. Zhang, J. -W. Wang, W. Zhou, C. Zhang and
S. Liu, Micropor. Mesopor. Mater.,2006, 88, 38.
16 Y. -P. Zhu, T. -Y. Ma, T. -Z. Ren, J. Li, G. -H. Du and Z. -Y. Yuan,
141/2014) and Start up Research Grant (Young Scientist)
(YSS/2015/000575) of Science and Engineering Research Board
(SERB), India for partial financial support. Authors are thankful
to Dr. L. Cardenas and C. Lorentz for XPS and solid-state NMR
studies respectively. Authors thank Dr. S. K. Das for stimulating
discussions on the work presented in the manuscript.
Appl. Catal. B, 2014, 156
Dalton Trans., 2010, 39, 9570; J. -L. Cao, Y. Wang, X. -L. Yu, S.
-R. Wang, S. -H. Wu and Z. -Y. Yuan, Appl. Catal. B, 2008, 79
-157, 44; T. -Y. Ma and Z. -Y. Yuan,
,
26; M. -F. Luo, J. -M. Ma, J. –Q. Lu, Y. -P. Song and Y. -J.
Wang, J. Catal., 2007, 246, 52.
17 S. Kirumakki, S. Samarajeewa, R. Harwell, A. Mukherjee, R. H.
Herber and A. Clearfield, Chem. Commun., 2008, 5556; A.
Dutta, A. K. Patra, H. Uyama and A. Bhaumik, ACS Appl.
Notes and references
Mater. Interfaces, 2013, 5, 9913; A. Dutta, M. Pramanik, A. K.
Patra, M. Nandi, H. Uyama and A. Bhaumik, Chem. Commun.,
2012, 48, 6738; R. Silbernage, T. C. Shehee, C. H. Martin, D.
T. Hobbs and A. Clearfield, Chem. Mater., 2016, 28, 2254; A.
Subbiah, D. Pyle, A. Rowland, J. Huang, R. A. Narayanan, P.
Thiyagarajan, J. Zoń and A. Clearfield, J. Am. Chem. Soc.,
2005, 127, 10826; M. D. M. Gómez-Alcántara, A. Cabeza, P.
Olivera-Pastor, F. Fernández-Moreno, I. Sobrados, J. Sanz, R.
E. Morris, A. Clearfield and M. A. G. Aranda, Dalton Trans.,
2007, 2394.
1
S. A. Corr, in Nanoscience: Volume 1: Nanostructures
Through Chemistry, ed. P. O’Brien, The Royal Society of
Chemistry, Cambridge, 2012, 180; J. L. G. Fierro, Metal
oxides: Chemistry and Applications, CRC Press, Boca Raton,
FL., 2006.
Functional Metal Oxide Nanostructures, ed. J. Wu, J. Cao, W.-
Q. Han, A. Janotti and H.-C. Kim, Springer, New York, 2012.
C. N. R. Rao, A. Müller and A. K. Cheetham, in The Chemistry
of Nanomaterials: Synthesis, Properties and Applications, ed.
C. N. R. Rao, A. Müller, A. K. Cheetham, Wiley-VCH Verlag
GmbH & Co. KGaA, Weinheim, 2006, 1; C. T. Dinh, T. D.
Nguyen, F. Kleitz and T. O. Do, in Controlled
Nanofabrications: Advances and Applications, ed. R.-S. Liu,
Pan Stanford Publishing, Singapore, 2012, 327.
S. M. Morris, P. F. Fulvio and M. Jaroniec, J. Am. Chem. Soc.,
2008, 130, 15210; H. Tian, X. L. Liang, L. Zeng and J. Gong,
ACS Catal., 2015, 5, 4959 and references therein.
J. Yang, K. Hidajat and S. Kawi, J. Mater. Chem., 2009, 19,
292.
H. Yang, C. Du, S. Jin, A. Tang and G. Li, Micropor. Mesopor.
Mater., 2007, 102, 204; C. K. Krishnan, T. Hayashi and M.
Ogura, Adv. Mater., 2008, 20, 2131; D. M. Hess, R. R. Naik, C.
Rinaldi, M. M. Tomczak and J. J. Watkins, Chem. Mater.,
2009, 21, 2125; B. Tian, X. Liu, H. Yang, S. Xie, C. Yu, B. Tu and
D. Zhao, Adv. Mater., 2003, 15, 1370; K. Zhu, B. Yue, W. Zhou
and H. He, Chem. Commun., 2003, 98; Y. M. Wang, Z. Y. Wu,
H. J. Wang and J. H. Zhu, Adv. Funct. Mater., 2006, 16, 2374.
For examples see: J. -D. Xiao, Q. Shang, Y. Xiong, Q. Zhang, Y.
Luo, S. -H. Yu and H. -L. Jiang, Angew. Chem. Int. Ed., 2016,
55, 9389; H. Li, M. M. Sadiq, K. Suzuki, R. Ricco, C. Doblin, A.
2
3
18 H. Wang and A. L. Rogach, Chem. Mater., 2014, 26, 123; A.
Corma, L. T. Nemeth, M. Renz and S. Valencia, Nature, 2001,
412, 423; A. Corma, M. E. Domine and S. Valencia, J. Catal.,
2003, 215, 294; J. Matsuo and M. Murakami, Angew. Chem.
Int. Ed., 2013, 52, 9109; P. Y. Dapsens, C. Mondelli, J.
Jagielski, R. Hauert and J. Pérez-Ramírez, Catal. Sci. Technol.,
4
2014,
19 R. Murugavel and M. P. Singh, New J. Chem., 2010, 34, 1846.
20 G. J. McCarthy and J. M. Welton, Powder Diffr.,1989, , 156.
4, 2302.
4
5
6
21 B. D. Cullity, Elements of X-ray Diffraction. Addison-Wesley
Publishing Co.: Boston, 1956.
22 M. Thommes, Chem. Ing. Tech., 2010, 82, 1059.
23 Karthik, T. V. K., Maldonado, A., Olvera, M. D. L. L. Electrical
Engineering, Computing Science and Automatic Control
(CCE), IEEE, 9th International Conference on 2012, 1.
24 A. Corsaro, M. A. Chiacchio and V. Pistara, Current Organic
Chemistry, 2009, 13, 482.
25 H. L. Rosenthal, Anal. Chem. 1955, 27, 1980.
26 M. R. Avhad and J. M. Marchetti, Renew. Sust. Energ. Rev.,
2015, 50, 696.
7
27 A. A. Kiss, A. C. Dimian and G. Rothenberg, Energy & Fuels,
2008, 22, 598.
J. Hill, S. Lim, P. Falcaro and M. R. Hill, Adv. Mater., 2016, 28
,
28 S. Das and V. Jayaraman, Prog. Mater. Sci., 2014, 66, 112-
255; J. P. Cheng, J. Wang, Q. Q. Li, H. G. Liu and Y. Li, Ind. Eng.
Chem. Res., 2016, 44, 1.
29 S. B. Patil, P. P. Patil and M. A. More, Sens. Actuators B:
Chem. 2007, 125, 126; J. Du, R. Zhao, Y. Xie and J. Li, Appl.
Surf. Sci., 2015, 346, 256; F. Yang and Z. Guo, J. Colloid
Interface Sci., 2016, 462,140.
1839; L. Chen, X. Chen, H. Liu and Y. Li, Small, 2015, 11, 2642;
T. Toyao, M. Saito, S. Dohshi, K. Mochizuki, M. Iwata, H.
Higashimura, Y. Horiuchi and M. Matsuoka, Chem. Commun.,
2014, 50, 6779.
H. Furukawa, K. E. Cordova, M. O’Kaeeffe and O. M. Yaghi,
Science, 2013, 341, 974 and references therein.
B. Wang, Z. Wang, Y. Cui, Y. Yang, Z. Wang and G. Qian, RSC
8
9
30 S. Mao, S. Cui, G. Lu, K. Yu, Z. Wen, J. Chen, J. Mater. Chem.
2012, 22, 11009; S. K. Lee, D. Chang, S. W. Kim, J Hazard
Mater., 2014, 268, 110; A. Kaur, R. Kumar, Sens. Actuators A,
2016, 245, 113; J. Samàa, S. Barthb, G. D. Gila, J. D. Pradesa,
N. Lópezc, O. Casalsa, I. Gràciad, C. Canéd, A. R. Rodrígueza,
Sens. Actuators B, 2016, 232, 402; S. K. Sinha, Adv. Mater.
Adv., 2015, 5, 84662.
10 L. Huang, H. Wang, J. Chen, Z. Wang, J. Sun, D. Zhao and Y.
Yan, Micropor. Mesopor. Mater., 2003, 58, 105.
11 K. J. Gagnon, H. P. Perry and A. Clearfield, Chem. Rev., 2012,
112, 1034.
12 C.-Y. Yang and A. Clearfield, React. Polym., Ion Exchangers,
Sorbents, 1987, 5,13.
Lett., 2015,
Hu, C. Xie, ACS Appl. Mater. Interfaces 2015,
6, 133; K. Xu, N. Li, D. Zeng, S. Tian, S. Zhang, D.
7
, 11359.
8 | J. Name., 2012, 00, 1-3
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ARTICLE
31 J. Shin, S. J. Choi, I. Lee, D. Y. Youn, C. O. Park, J. H. Lee, H. L.
Tuller, D. Kim, Adv. Funct. Mater., 2013, 23, 2357; J. Li, P.
Tang, P. Zhang, Y. Feng, R. Luo, A. Chen, Ind. Eng. Chem., Res.
2016, 55, 3588; W. Tang, J. Wang, Q. Qiao, Z. Liu, X. Li, J.
Mater. Sci., 2015, 50, 2605; S. Singkammo, A. Wisitsoraat, C.
Sriprachuabwong, A. Tuantranont, S. Phanichphant, C.
Liewhiran, Appl. Mater. Interfaces, 2015,
Narjinary, P. Rana, A. Sen, M. Pal, Mater. Des., 2017, 115
158; S. J. Choi, B. H. Jang, S. J. Lee, B. K. Min, A. Rothschild, D.
Kim, Appl. Mater. Interfaces, 2014, , 2588.
32 J. Fawcett, A. W. G. Platt, S. Vickers, Polyhedron, 2003, 22
7, 3077; M.
,
6
,
1431; S. -F. Tang, X. –B. Pan, X. –X. Lv, S. –H. Yan, X. –R. Xu, L.
–J. Li, X. –B. Zhao, CrystEngComm., 2013, 15, 1860.
33 A. I. Vogel, A Text-book of Practical Organic Chemistry, 3rd
edition, London Group Limitted, 1956; M. M. Hania, E-
journal of chemistry, 2009, 6, S508.
34 M. Chai, Q. Tu, M. Lu, Y. J. Yang, Fuel Processing Technology
2014, 125, 106.
35 J. A. Aricetti, M. Tubino, J. Am. Oil Chem. Soc., 2012, 89
2113.
,
36 J. K. Satyarthi, D. Srinivas, P. Ratnasamy, Energy & Fuels,
2009, 23, 2273.
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