Carboxyethyltin and transition metal co-functionalized tungstoantimonates composited with polypyrrole for enhanced electrocatalytic methanol oxidation

Article abstract of DOI:10.1039/c8dt05118f

Carboxyethyltin and first-row transition metals (TMs) were firstly introduced into trivacant Keggin-type tungstoantimonate in an aqueous solution, leading to the formation of four crystalline organic-inorganic hybrid sandwich-type polyoxometalates (POMs),

Full text of DOI:10.1039/c8dt05118f

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Efficient extraction of sulfate from water using
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DOI: 10.1039/C8DT05118F
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ARTICLE
Carboxyethyltin and transition metal co-functionalized
tungstoantimonates composited with polypyrrole for enhanced
electrocatalytic methanol oxidation
Received 00th January 20xx,
Accepted 00th January 20xx
a
a
a
a
a
a
DOI: 10.1039/x0xx00000x
Hai-Dan Wang, Xing-Fang Wang, Fang Su, Jian-Sheng Li, Lan-Cui Zhang,* Xiao-Jing Sang,* Zai-
Ming Zhu*
a
www.rsc.org/
Carboxyethyltin and first-row transition metal (TM) were firstly introduced into trivacant Keggin-type tungstoantimonate
in aqueous solution, leading to the formation of four crystalline organic-inorganic hybrid sandwich-type polyoxometalates,
formulated as Na10-x-y
y = 0, 5, 5, 2; n = 18, 24, 24, 22, respectively). SbW
Meanwhile, SbW -TM-SnR was composited with polypyrrole (PPy) through an electropolymerization process, forming PPy-
SbW -TM-SnR, on which platinum (Pt) was further electro-deposited to prepare PPy-SbW -TM-SnR/Pt for electrocatalytic
methanol (CH OH) oxidation in acid solution. The composition and morphology of PPy-SbW -TM-SnR/Pt were determined
by IR, scanning electron microscope (SEM), energy disperse spectroscopy (EDS) and X-ray photoelectron spectroscopy
XPS). The electrochemical experiment results show that SbW -TM-SnR and PPy obviously enhance the electrocatalytic
and anti-intoxication abilities of Pt, and the highest peak current density of 0.87 mA cm , corresponding to 1.85 and 1.43
K H
y x
2
[((TM)(H O)
3
)
2
(Sn(CH
2
)
2
COO)
2 9 33 2 2 9
(SbW O ) ]·nH O (SbW -TM-SnR, TM = Mn, Co, Ni, Zn; x = 1, 1, 0, 0;
9
-TM-SnR exhibit high catalytic ability for the oxidation of cyclohexanol.
9
9
9
3
9
(
9
-2
9
times higher than those of pure Pt and PPy/Pt electrodes separately, is acquired for PPy-SbW -Ni-SnR/Pt composite
electrode. These findings may enlarge the application of PPy and POMs in electrocatalytic field.
without structure changes owing to their excellent redox
1
0
Introduction
Methanol oxidation reaction (MOR) is the anodic half-reaction
property and high stability. In recent years, POMs have been
broadly used in a variety of electronic devices such as solar
cells, lithium-ion batteries, capacitors, liquid-flow cells and fuel
1
in direct methanol fuel cells (DMFCs), and the performance of
1
1–16
cells.
For CH
3
OH electrooxidation, Keggin-type POMs
40] , M = W, Mo) have been applied to increase the
performance of Pt by acting as a kind of electron mediators
Moreover, POMs could effectively promote
the electrochemical oxidation of carbon monoxide (CO) to
anode catalysts is a determinant of the overall efficiency of
3
−
([PM12O
2
fuel cells. At present, Pt-based materials are still necessary
anodic electrocatalysts in acidic medium for CH
electrooxidation, although some Pt-free materials such as
CeO /Nano-ZSM-5, SnO /m-ZSM-5 and Pd/C(PDA) have been
2 2
3
OH
1
7,18
and stabilizers.
3
1
9
carbon dioxide (CO
2
) in an aqueous solution. It has been
reported that sandwich-type ruthenium-containing POM
proved to be active to CH
3
OH electrooxidation in alkaline
solution.4 However, Pt has the disadvantage of high cost, and
the more prominent is that the active sites on pure Pt are
easily adsorbed and blocked by COads-like intermediate
products, causing the delay of further reactions, and this
poisoning phenomenon is particularly obvious in an acidic
-6
1
0−
[
{Ru
electrocatalytic activity towards oxidation of ethanol and
CH OH, yielding aldehydes and acids with total faradaic
4 4
O (OH)
2
(H
2
O)
4
}(γ-SiW10
O
36 2
) ]
shows
efficient
3
2
0
efficiencies exceeding 94%. As a result, the main merit of
POMs in MOR is that the physicochemical properties of POMs
can be easily adjusted by structure and composition
modifications.
Carboxyethyltin decorated POMs are a new class of unique
POM-based organic-inorganic hybrids. In our recent work, it is
found that the functionalities of POMs, such as photoelectric,
electrocatalytic and oxidation catalytic activities, can be
enhanced by introducing carboxyethyltin group.
Furthermore, the composites of POM-estertin derivatives with
2 2 2 2 9
), e.g. TiO /P W15-Co-SnR and TiO /PW -
Co-SnR, exhibit photoelectrocatalytic activity for oxidation of
7
electrolyte, which limits its practical use. Therefore, many
strategies have been implemented for modification of Pt to
further improve its catalytic activity and stability.
Polyoxometalates (POMs) are a class of anionic nano-sized
metal-oxygen clusters and can transfer electrons and protons
8
,9
a. School of Chemistry and Chemical Engineering, Liaoning Normal University,
Dalian 116029, China. E-mail:
zhanglancui@lnnu.edu.cn;sangxj923@nenu.edu.cn; chemzhu@sina.com; Fax:
21‒25
titanium dioxide (TiO
+
86 411 82158559; Tel: +86 411 82159780.
Electronic Supplementary Information (ESI) available: ORTEP views and packing
arrangement of SbW -TM-SnR (TM = Mn/Co/Ni/Zn); IR, XRPD, TG, Solid diffuse
†
9
2
6
3
CH OH. Unfortunately, good electrocatalytic performance
was not got in this system, which may be due to the poor
reflection absorption spectra, XPS, catalytic oxidation and electrocatalytic CH
oxidation results. CCDC reference numbers: 1885004 – 1885007.
3
OH
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Journal Name
conductivity and low catalytic activity. Herein, considering the for 30 min. Finally, the measurements were conducted in the
View Article Online
DOI: 10.1039/C8DT05118F
−1
excellent modification effect of carboxyethyltin group on potential range from 0 to 1.0 V at a scan rate of 50 mV s .
POMs, as an extension of our work, four cases of Synthetic procedures
carboxyethyltin and TM co-functionalized tungstoantimonates
9 33 2
O ) ]·
Synthesis of Na
4H O (SbW
mmol), Cl Sn(CH
·6H O (0.087 g, 0.3 mmol) were dissolved respectively
in 10.0 mL of 0.4 mol L NaAc-HAc buffer solution (pH ≈ 5.0)
to form solution A, B and C, respectively. Then solution B was
slowly added to solution A, and stirred at 80 °C for 1 h, and
then solution C was added dropwise to the above solution, and
stirred for another 2 h. After cooling to room temperature, a
4
K
5
H[(Co(H
2
O)
3
)
2
(Sn(CH
2
)
2
COO)
2
(SbW
(0.286 g, 0.1
(0.062 g, 0.2 mmol) and
Na10-x-y
K
y
H
x
[((TM)(H
-TM-SnR, TM = Mn, Co, Ni, Zn; x = 1, 1, 0, 0; y = 0, 5, 5, 2;
n = 18, 24, 24, 22, respectively) were designed and synthesized.
2 3 2 2 2 2 9 33 2 2
O) ) (Sn(CH ) COO) (SbW O ) ]·nH O
2
2
9
-Co-SnR). A Parent POM Na-SbW
COOCH
9
(SbW
9
3
)
2 2
3
Co(NO
)
3 2
2
Moreover, PPy-SbW
through an electropolymerization process, and were further
used to fabricate PPy-SbW -TM-SnR/Pt composite electrodes
with electro-deposition method. Their electrocatalytic activity
9
-TM-SnR composites were prepared
−1
9
3
towards oxidation of CH OH was explored.
2 3
certain amount of guanidine hydrochloride (C(NH ) Cl)
aqueous solution and KCl (s) were added to the obtained
solution. Slow evaporation of the aqueous solution at 50 °C
resulted in purple block crystals (yield: ca. 68.9% based on W)
Experimental
Materials and methods
of SbW
9
-Co-SnR after about three days. Anal. calcd for
Na Co Sn -Co-SnR): C 1.21, H 1.17, K
.29, Na 1.55, Sb 4.10, Co 1.99, Sn 4.00, W 55.74%; found: C
Cl
(
(
3
Sn(CH
Na-SbW
Co-SbW
2
)
2
COOCH
3
, parent POMs Na
9
[B-α-SbW
9
O
33]·19.5H
2
O
O
6 69
C H K
3
5
4
O100Sb
2
2
2 9
W18 (SbW
9
) and Na10[Co
2
(WO (B-β-SbW
)
2 2
9 33 2
O ) (H
2
O) ]·40H
6
2
9
2
) were synthesized according to the literature
7,28
1.26, H 1.13, K 3.30, Na 1.51, Sb 4.05, Co 2.04, Sn 4.06, W
methods.
2 6 2
H PtCl ·6H O and Pyrrole were purchased from
5
5.67%.
Aladdin. All other reagents were of analytical grade and were
not further purified before use. FTO conductive glass was
purchased from HEPTACHROMA and used as substrate for
electrochemical tests. The experimental water was double-
distilled water with the resistivity of 16 ‒ 18 МΩ cm . C and H
elemental analysis was performed with a Vario Elcube
elemental analyzer, and Na, K, Sb, Sn, Mn, Co, Ni, Zn and W
were analyzed with a Prodigy XP emission spectrometer. Single
crystal X-ray diffraction data were collected on a Bruker Smart
APEX II X-diffractometer equipped with graphite-
monochromated Mo Kα radiation (λ = 0.71073 Å). IR spectra
Synthesis of SbW
9
-TM-SnR (TM = Mn, Ni, Zn). The synthetic
O) (Sn(CH COO) (SbW ]·18
[(Ni(H (Sn(CH
-Ni-SnR) and Na [(Zn(H
]·22H O (SbW
-Co-SnR by only replacing Co(NO
mmol) with MnCl ·4H O (0.059 g, 0.25 mmol), Ni(NO
0.088 g, 0.3 mmol), ZnSO ·7H O (0.086 g, 0.3 mmol) (yield: ca.
8.7%, 69.0% and 68.8% based on W), respectively. Anal. calcd
Mn Sn -Mn-SnR): C 1.26, H 1.00,
methods of Na
O (SbW -Mn-SnR), Na
]·24H O (SbW
COO) (SbW
SbW
9
H[(Mn(H
2
)
3 2
)
2 2
2
9 33 2
O )
H
2
9
5
K
5
2
O)
3
)
K
2
2
)
2
COO)
2
(SbW
9
2
−1
O )
33 2
2
9
8
2
2
O) (Sn(CH )
3
)
2
2
2
O )
9 33 2
2
9
-Zn-SnR) are similar to that of
·6H O (0.087 g, 0.3
2
·6H O
9
)
3 2
2
2
2
)
3 2
(
6
4
2
6
for C H57Na
9
O94Sb
2
2
2 9
W18 (SbW
Na 3.61, Sb 4.24, Mn 1.91, Sn 4.14, W 57.65%; found: C 1.30, H
1.05, Na 3.58, Sb 4.20, Mn 1.89, Sn 4.18, W 57.61%.
(KBr pellets) were recorded on a Bruker AXS TENSOR-27 FTIR
−1
spectrometer in the range of 4000 – 400 cm . TG analysis was
performed on a Pyris Diamond TG-DTA thermal analyzer at the
heating rate of 10 °C min−1 in air atmosphere. The solid diffuse
6 68
C H K
5
Na
5 2 2 2 9
O100Sb Ni Sn W18 (SbW -Ni-SnR): C 1.21, H 1.14, K
3.28, Na 1.93, Sb 4.09, Ni 1.97, Sn 3.98, W 55.53%; found: C
1
5
1
.24, H 1.17, K 3.31, Na 1.97, Sb 4.11, Ni 2.00, Sn 4.02, W
5.41%. C Na Zn Sn -Zn-SnR): C 1.22, H
.09, K 1.33, Na 3.12, Sb 4.14, Zn 2.22, Sn 4.03, W 56.20%;
reflectivity spectra were collected on a Cary series UV-Vis
spectrophotometer in absorption mode, which was measured
6 64
H K
2
8
O98Sb
2
2
2 9
W18 (SbW
from 200 to 800 nm using BaSO
reflectance. Field emission scanning electron microscopy
FESEM) was performed on Hitachi SU-8010. XRPD data were
collected on a Bruker AXS D8 Advance diffractometer using Cu
Kα radiation (λ = 1.5418 Å) in the 2θ range of 5 ‒ 50° with a The structures were solved by direct methods and refined on
step size of 0.02 °. XPS was operated on a VG ESCALAB MKII
by full- matrix least-squares fitting using SHELXTL-2014.29 An
4
as a standard with 100%
found: C 1.26, H 1.06, K 1.39, Na 3.05, Sb 4.10, Zn 2.28, Sn
.95, W 56.26%.
X-ray crystallography
3
(
2
F
spectrometer using Mg Kα (1253.6 eV) achromatic X-ray empirical absorption correction was applied by using the
source. All electrochemical experiments were performed with SADABS program. Cell parameters were obtained by the global
a CHI604B electrochemical workstation (Shanghai Chenhua refinement of the positions of all collected reflections.
Instrument Corp, China) at room temperature. A three- Hydrogen atoms on C atoms were added in calculated
electrode system was employed with a platinum wire as the positions. Crystal data and structure refinement parameters of
counter electrode, an Ag/AgCl electrode as the reference SbW -TM-SnR are listed in Table 1. Selected bond lengths,
9
electrode and the hybrids films electro-deposition on FTO angles and hydrogen bonds are listed in Tables S1‒S8 (ESI†).
2
electrode with an effective area of 1.0×1.0 cm as the working CCDC reference numbers: 1885004–1885007.†
electrode. For CO stripping experiments, first of all, CO was Catalytic oxidation of cyclohexanol to cyclohexanone
adsorbed on the prepared Pt-based catalysts by purging CO in
the solution at the potential of 0.2 V for 15 min. Then, the The catalytic experement refers to the method described in
3
0
dissolved CO was removed from the electrolyte by purging N
2
our previous work. In a typical experiment, cyclohexanol (9.6
mL), catalyst (SbW -TM-SnR or parent compounds, 0.03 mmol)
9
2
| J. Name., 2012, 00, 1-3
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Table 1 Crystal and refinement data for SbW
9
-TM-SnR (TM = Mn, Co, Ni, Zn)
View Article Online
DOI: 10.1039/C8DT05118F
Compound
Formula
SbW
9
-Mn-SnR
Mn Sn
SbW
Na
9
-Co-SnR
Co
SbW
Na
9
-Ni-SnR
Ni
SbW
Na
9
-Zn-SnR
2 2 18
Zn Sn W
C
6
H
9
57Na O
94Sb
2
2
W
2 18
C
H K
6 69 5
4
O
100Sb
2
2
Sn
W
2 18
C
H K
6 68 5
5
O
100Sb
2
2
Sn
W
2 18
C
H K
6 64 2
8
O
98Sb
2
Formula weight
5740.48
296(2)
0.71073
Triclinic
Pī
5937.11
296(2)
0.71073
Triclinic
Pī
5958.65
296(2)
0.71073
Triclinic
Pī
5887.61
296(2)
0.71073
Triclinic
Pī
T/K
Wavelength/Å
Crystal system
Space group
a/Å
b/Å
c/Å
α/°
β/°
γ/°
V/Å 3 , Z
12.621(3)
12.751(2)
16.797(3)
93.553(3)
110.782(3)
99.534(3)
2470.8(8)
12.4391(12)
12.6196(12)
16.3813(16)
94.581(2)
109.896(2)
101.759(2)
2335.9(4)
4.220, 2632
0.979
12.4828(18)
12.6293(17)
16.440(2)
94.595(2)
109.959(2)
101.665(2)
2354.3(6)
4.203, 2644
1.037
12.4709(19)
12.6542(18)
16.428(2)
94.899(2)
109.885(3)
101.197(3)
2359.0(6)
4.144, 2604
1.093
Dc/g cm −3 , F 000
GOF
3.858, 2528
1.031
Reflections collected
12707
12118
12005
11121
R
int
0.0288
0.0329
0.0389
0.0471
θ Range (°)
(I > 2σ(I)) a
(all data) a
1.633-25.000
0.0417
1.340-25.000
0.0365
1.335-24.999
0.0419
1.336-25.000
0.0955
R
1
wR
2
0.1192
0.0788
0.0977
0.3894
aR
2
2)2]/∑[w(F
2 2 1/2
1
= ∑||F
o
| − |F ||/∑|F
c
o
|, wR
2
= ∑[w(F
o
− F
c
o
) ]
and acetonitrile (10.0 mL) were added into 100 mL three-
necked round-bottom flask with water condenser, and 30% of
H O (20.0 mL) as oxidant was slowly added dropwise to the
2 2
Results and discussion
mixture over 3 h with the reaction temperature of about 88 °C.
After completing the reaction, the solvent acetonitrile was
removed by distillation, and thus organic and inorganic phases
could be separated by separatory funnel extraction method,
and the catalyst was remained in the reaction vessel. The
reaction products were characterized by gas chromatography.
Preparation of PPy-POM/Pt composite films
Synthesis
By using Na-SbW as an inorganic building block, estertin
3
Cl Sn(CH COOCH as an organic precursor, and TM ions as
9
3
2
)
2
modified components, new POM-based organic-inorganic
hybrids are successfully constructed by carefully adjusting the
synthetic conditions. As seen from Scheme 1, step I, when
selecting double-distilled water as a solvent, only powders
were obtained as the molar ratio range of Na-
Primarily, FTO glasses were ultrasonically cleaned with
detergent solution, double-distilled water, acetone and
ethanol successively. Then it was processed with piranha
solution for 30 minutes, and rinsed with double-distilled water
SbW
9
:estertin:TM was from 1:2:2 to 1:4:4. Considering the
sensitivity of lacunary POM to pH in aqueous solution, a buffer
solution of 0.4 mol L NaAc-HAc (pH ≈ 5.0) was selected as a
solvent with refer to the stable pH value of [SbW O ] (SbW )
9 33 9
−1
2
and dried under a stream of N , standby for application. First
9−
of all, PPy-POM composite films were prepared by
potentiostatic electropolymerization under + 0.65 V in a three-
electrode system consisting of the cleaned FTO glass as the
working electrode, Ag/AgCl as the reference electrode and Pt
wire as the counter electrode. The electrolyte solution was
subunit, and the influence of the molar ratio of the reactants
on the formation of crystalline products was investigated. As
shown in Scheme 1, step II, when the molar ratio was 1:2:2,
1
:3.5:3.5 and 1:4:4, respectively, no crystal was obtained.
While, at the same pH (5.0), the molar ratio was changed to
:(2.5−3):(2.5−3), four new crystalline Keggin sandwich-type
tungstoantimonates (SbW -TM-SnR, TM = Mn, Co, Ni, Zn) were
−1
−1
composed of 0.1 mol L pyrrole, 1.0 mmol L POM (SbW
9
-
1
TM-SnR) and 0.02 mol L− tetrabutylammonium bromide. The
1
9
prepared films were rinsed with double-distilled water and
dried under a stream of N . Subsequently, Pt particles were
2
deposited on the surface of PPy-POM composite film-modified
successfully obtained (Scheme 1, step ΙΙIa). It is found that
these four tungstoantimonates are isostructural although
containing different TM ions. And it is worth noting that the
FTO electrodes in situ by potentiostatic electrodeposition at ‒
POM unit B-α-SbW
Step IIIb), furthermore,
COOCH
9
has converted to B-β-SbW
the original
]3+ group has hydrolyzed into carboxyethyltin
9
(Scheme 1,
estertin
−1
0
.2 V in a 0.5 mol L−1
2 4
H SO solution containing 1.0 mmol L
2 6
H PtCl , and the polymerization time was 150 s, followed by
[
[
Sn(CH
Sn(CH
2
)
)
2
3
rinsing with double-distilled water and drying under N
atmosphere.
2
2+
2
2
COO] group during this synthetic process (Scheme
1
, Step IIIc). As can be seen from our synthetic strategies for
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DOI: 10.1039/C8DT05118F
Scheme 1 Schematic representation of the formation of SbW
9
-TM-SnR (TM = Mn/Co/Ni/Zn).
atoms (O11, O20, O24) in three WO
6
octahedra and three
water molecules (O1W, O2W, O3W). Each Sn1/Sn1' atom
coordinates with four terminal oxygen atoms (O4, O6, O22,
O23) from four WO
oxygen atom O34 from a [Sn(CH ) COO] . Sn1, Sn1', W1 and
6
octahedra and a carbon atom C1 and an
2
+
2 2
W1' form a close ring through sharing-briged atoms O4, O4',
O6 and O6'. The bond lengths of Sn‒O and Sb‒O are in the
range of 2.02(4) ‒ 2.188(10) Å and 1.991(9) ‒ 2.034(10) Å,
separately. The Sn‒C bond lengths are 2.113(16) ‒ 2.148(12)
Å. The W‒O and TM‒O distances are in the range of 1.66(4) ‒
2
.38(4) Å and 2.00(8) ‒ 2.240(13) Å, respectively (Tables
9
Fig. 1 Single crystal structure of SbW -TM-SnR (TM = Mn, Co, Ni, Zn), the polyhedral
S1‒S4, ESI†). In SbW -TM-SnR, the sandwich-type
9
and ball-and-stick representation of the isostructural polyoxoanions (a); the ball-and-
stick representation of the central belt (b) (H atoms, K and Na cations, and free water
molecules have been omitted for clarity).
+
+
polyoxoanions and Na /K cations, free water molecules are
accumulated to form 3D supramolecular frameworks by
OW‒H···O/OW hydrogen bonds (2.24(4) ‒ 3.369(16) Å)
(Tables S5‒S8, ESI†) between water molecules and the
polyoxoanions or among water molecules, as well as the
9
SbW -TM-SnR, through controlling pH and molar ratio of the
reactants, the carboxyethyltin and TM ions co-functionalized
Keggin sandwich-type organic-inorganic hybrids based on
+
+
electrostatic forces between Na /K
cations and
trivacant SbW
9
POM can be prepared after crystallization
polyoxoanions (Fig. S2, ESI†).
process.
Characterization
Structural analysis
Single crystal X-ray structure analysis indicates that the
polyoxoanions of SbW -TM-SnR display the well-known
Keggin sandwich-type structures (Fig. 1). In the four
compounds, the B-β-SbW unit can be regarded as an isomer
of B-α-SbW , in other words, the in-plane rotation of one
edge-shared {W
above B-β-SbW
was found to be hydrolyzed into carboxyethyltin
IR spectra. IR spectra of SbW
Zn) (Fig. S3, ESI†) are similar. As shown in Fig. S3 (ESI†), the
9
-TM-SnR (TM = Mn, Co, Ni,
−1
vibration peaks between 950 and 670 cm are attributed to
ν(W=O ), ν(Sb–O ), ν(W, TM–O ) and ν(W–O ) (O , O , O and
c
O are terminal, tetrahedral, edge- and corner-sharing oxygen
9
t
a
c
b
t
a
b
9
3
1,32
−1
atoms).
The peaks at 503–509 cm are assigned to the
9
o
antisymmetric and symmetric vibrations of Sn–C bonds, and
the stretching vibrations of Sn–O bond are at 467–495 cm−1
The bands at 1648–1571 cm
3
O
13} fragment in B-α-SbW
unit. Estertin precursor [Sn(CH ) COOCH ]
9
by 60 yields the
3
+
.
33
9
2 2 3
−1
−1
and 1345–1360 cm
COO]2+ during the reaction process. In SbW
Sn(CH -TM-
SnR, each symmetrical unit consists of a B-β-SbW subunit
modified by one Mn/Co/Ni/Zn ion and one carboxyethyltin
group (Fig. S1, ESI†). The polyoxoanion structures in SbW
TM-SnR are isostructural, and the central belt contains two
symmetrical inner organotin groups, and two (TM)O (i.e.
MnO /CoO /NiO /ZnO ) fragments located in the outer
correspond to vas(COO) and vs(COO) vibrations,
[
)
2 2
9
3
4
respectively. The broad bands of lattice water molecules
9
−1
are located at 3400–3424 cm . The peaks at 2917–2924 and
−1
9
-
2849–2861 cm
vibrations of the organic group (–CH
that carboxyethyltin group and POM framework exist in
SbW -TM-SnR, which are in good agreement with the single-
crystal structural analysis.
are attributed to the characteristic
).24 IR spectra indicate
2
6
6
6
6
6
9
opposite positions (Fig. 1a). As shown in Fig. 1b, each
Mn/Co/Ni/Zn ion was matched with three terminal oxygen
4
| J. Name., 2012, 00, 1-3
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ARTICLE
Thermal gravimetric (TG) analysis. The thermal stability of
SbW -TM-SnR was investigated by TG curves in the range
Fig. S7 (ESI†) that the experimental values of the four powder
samples match well with the simulated values of their single
View Article Online
DOI: 10.1039/C8DT05118F
9
from room temperature to 1000 °C (Fig. S4, ESI†). As shown
in Fig. S4 (ESI†), the four compounds exhibit similar three-
step continuous weight loss processes. The first weight loss in
the ranges of 36–366, 36–388, 36–254 and 36–399 °C is 5.95,
7
.13, 7.46 and 6.22%, respectively (corresponding to the
calculated values of 5.64, 7.28, 7.28 and 6.73%), owing to the
loss of crystal water molecules in SbW -Mn-SnR, SbW -Co-
SnR, SbW -Ni-SnR and SbW -Zn-SnR, respectively. The last
two step weight losses of 4.22% at 268–913 °C for SbW -Ni-
SnR meet the theoretical value (4.23%) of loss of
coordination water molecules and (CH COO groups. While
for SbW -Mn-SnR, SbW -Co-SnR and SbW -Zn-SnR, the last
two weight losses of 2.98, 2.89 and 2.29% at 355–823 °C,
88–863 °C and 388–887 °C respectively are all lower than
the calculated values (4.39, 4.25 and 4.28%), which means
that SbW -TM-SnR (TM = Mn, Co, Zn) only lose coordination
water molecules and part of (CH COO groups. The above
9
9
9
9
9
2 2
)
9
9
9
3
9
2 2
)
analytical results show that the carboxyethyltin and TM co-
functionalized sandwich-type tungstoantimonates have
higher thermal stability, which are also verified by IR spectra
Fig. 2 119Sn NMR spectra of SbW
O.
9
9 9
-Co-SnR (a), SbW -Ni-SnR (b) and SbW -Zn-SnR (c) in
D
2
of SbW
in air (Fig. S5, ESI†). As seen from Fig. S5 (ESI†), at 380, 520,
and 800 °C, the characteristic peaks of POM and CH group
are still retained and up to 800 °C, meanwhile the
9
-TM-SnR samples burned at different temperatures
2
s
characteristic peaks of vas(COO) and v (COO) are also
maintained in spite of a little blue shifts.
Solid diffuse reflection absorption spectra. The optical
absorption behavior of SbW -TM-SnR was studied by solid
diffuse reflection absorption spectroscopy. It can be seen
that SbW -TM-SnR (TM = Mn, Co, Ni, Zn) display a strong
absorption band emerging in the λ range from 200 to 400 nm
Fig. S6, ESI†), and the max absorbance is at 318, 315, 325
and 316 nm, respectively, which should be attributed to
9
9
(
3
5
oxygen to metal (Obridging→W) charge transfer transition.
Moreover, SbW -Co-SnR shows an extra absorption band
from 450 to 650 nm, and SbW -Ni-SnR shows two extra
9
9
absorption bands from 370 to 800 nm in the visible region,
which can be attributed to d–d transition of Co/Ni ions.
NMR analysis. The structures of SbW
Co, Ni, Zn) were further confirmed by Sn NMR spectrum
9
-TM-SnR (TM = Mn,
Fig. 3 CV curves of SbW
9 9 9 9
-Mn-SnR (a), SbW -Co-SnR (b), SbW -Ni-SnR (c), and SbW -
1
19
Zn- SnR (d) in 0.4 mol L−1 NaAc-HAc solution (pH = 5).
(Fig. 2). From the results shown in Fig. 2a‒c, it is found that
the chemical shifts (δ) at ‒ 519.06, ‒ 491.75 and ‒ 509.32
crystals, indicating that the four compounds are pure phase.
The difference of peak strength may be due to the different
orientation of samples, the destruction of crystal water
during the test and the change of specimen shape.
ppm of 1 Sn for SbW
19
-Co-SnR, SbW
-Ni-SnR and SbW
-Zn-
9
9
9
1
19
SnR have shifted to high field compared with the Sn NMR
3 2 2 3
peak of precursor Cl Sn(CH ) COOCH
(δ = ‒ 115.51 ppm),3
6
which is due to the increased electron density on Sn atom.
The result shows that the organotin group has been
Cyclic voltammetry (CV). In order to study the
9
electrochemical behavior of SbW -TM-SnR (TM = Mn, Co, Ni,
1
19
successfully incorporated into the POM system. While Sn
NMR signal of SbW -Mn-SnR was not detected under our
experiment condition because of its low solubility and
−1
Zn), the CV curves of four compounds in 0.4 mol L NaAc-
HAc buffer solution (pH = 5.0) were obtained at the scan rate
9
−1
of 50 mV s (Fig. 3). As shown in Fig. 3, in the voltage range
from 0 to ‒ 1.0 V vs Ag/AgCl, SbW -TM-SnR all exhibit one
pair of redox peaks (I-ľ) located at ‒ 0.777 and ‒ 0.644 V, ‒
2
+
paramagnetism of Mn .
9
X-ray powder diffraction (XRPD). The XRPD spectra of
SbW -TM-SnR are used to test the purity of these
9
compounds (Fig. S7, ESI†). It can be seen from the graphs in
0
0
.760 and ‒ 0.630 V, ‒ 0.786 and ‒ 0.630 V, ‒ 0.755 and ‒
.647 V, respectively, which are assigned to the redox
3
5
process of W centers. Meanwhile, there are also another
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ARTICLE
Journal Name
reduction peak (II) for SbW
9
-TM-SnR (TM = Mn, Co, Ni, Zn) at
simple TM salts (MnCl
View Article Online
2 2 3 2 2 3 2 2
·4H O, Co(NO ) ·6H O, Ni(NO ) ·6H O
DOI: 10.1039/C8DT05118F
‒
0.542, ‒ 0.516, ‒ 0.531 and ‒ 0.510 V, respectively. To
and ZnSO ·7H O) and the precursor estertin have been
4
2
Fig. 4 Influence of reaction time (a) and catalyst dosage (n(cyclohexanol)/n(W)) (b) on
cyclohexanol conversion using SbW -Ni-SnR as a catalyst.
9
attribute this, the CV curves of precursor estertin and Na-
SbW were recorded. For estertin, it has one irreversible
reduction peak located at ‒0.662 V (Fig. S8, ESI†). Na-SbW
has one pair of peaks (I-ľ) located at ‒ 0.679 and ‒ 0.594 V
Fig. S9, ESI†), corresponding to the redox process of W
center. In comparison with Na-SbW , the redox peaks of W
centers for SbW -TM-SnR (TM = Mn, Co, Ni, Zn) show
negative shifts, which is manifested in the previous work.
Comprehensive comparison of these CV results, the peak (II)
in CVs of SbW -TM-SnR (TM = Mn, Co, Ni, Zn) belongs to the
9
9
9
Fig. 5 IR spectra of PPy-SbW -TM-SnR (TM = Mn, Co, Ni, Zn).
(
9
9
3
7,38
9
signal of Sn center. Moreover, from Fig. 3a, we can see one
pair of redox peaks (III-IIľ) located at 0.632 and 0.924 V,
3
9
which are due to the redox process of Mn ion.
Catalytic oxidation performance
In this paper, the oxidation of cyclohexanol to cyclohexanone
by H was selected as a model reaction to study the
oxidation catalytic performance of SbW -TM-SnR (TM = Mn,
Co, Ni, Zn). Using SbW -TM-SnR as a catalyst and H as an
oxidant with the molar ratio of 1:2.2 for cyclohexanol to
2
O
2
Fig. 6 SEM images of PPy-SbW
Ni-SnR/Pt (c), PPy-SbW -Zn-SnR/Pt (d) composite films, Pt microparticles (e) on FTO
and EDS of PPy-SbW -Ni-SnR/Pt composite (f).
9
9 9
-Mn-SnR/Pt (a), PPy-SbW -Co-SnR/Pt (b), PPy-SbW -
9
9
9
9
2 2
O
2
8
evaluated. The conversions of cyclohexanol are listed in Table
S9 (ESI†), from which it can be seen that the catalytic
2 2
H O ,
the effects of catalyst dosage and reaction time on
the conversion of cyclohexanol were explored.
Taking SbW -Ni-SnR as an example, the catalytic oxidation
of cyclohexanol was carried as the follows: 0.030 mmol
SbW -Ni-SnR, 20.0 mL of 30% H , 9.6 mL of cyclohexanol
performance of SbW
of Na-SbW , TM salts and estertin. The conversions of
cyclohexanol are 88.7, 92.1 94.6 and 91.2% for SbW -Mn-
SnR, SbW -Co-SnR, SbW -Ni-SnR and SbW -Zn-SnR,
respectively. As a result, SbW -TM-SnR is proved to be a
9
-TM-SnR is obviously higher than those
9
9
2 2
O
9
9
and 10.0 mL of acetonitrile were added into the reaction
system, and the reaction temperature was about 88 °C (Fig.
9
9
9
9
good kind of oxidation catalysts. The introduction of SnR
group and TM ions is able to obviously enhance the catalytic
oxidation activity of the sandwich-type tungstoantimonate.
4
). As can be seen from Fig. 4a, the conversion of
cyclohexanol reaches 94.6% at 3 h, and further increasing
reaction time results in a little increase of conversion, so, the
best reaction time is determined to be 3 h. Under the
reaction time of 3 h and the other reaction conditions
remaining unchanged, when the molar ratio of
9
Characterization of PPy-SbW -TM-SnR/Pt composite film
In viewing of good redox property, SbW -TM-SnR was used
9
for assistant electropolymerization of pyrrole, forming PPy-
W/cyclohexanol is 1:200, that is, the dosage of SbW
9
-Ni-SnR
SbW -TM-SnR composite on the FTO substrate, on which Pt
9
is 0.030 mmol, the cyclohexanol conversion reaches the
maximum (94.6%) (Fig. 4b). Moreover, when the catalyst
dosage is 0.017 mmol, the conversion rate of cyclohexanol
can still reach up to about 85%, which shows that the catalyst
shows good catalytic oxidation activity.
was further deposited to prepare PPy-SbW -TM-SnR/Pt
composite. Here, PPy can improve electrical conductivity as a
9
conductive polymer, and SbW -TM-SnR is expected to
9
modulate the catalytic activity of Pt.
IR spectra of PPy-SbW -TM-SnR (TM = Mn, Co, Ni, Zn)
9
Subsequently, under the above determined optimum
reaction conditions, that the reaction time is 3 h and the
dosage of the catalyst is 0.030 mmol, the catalytic oxidation
composite materials all contain four absorption bands
between 1000 and 600 cm−1, which are assigned to the
characteristic peaks of ν(W=O ), ν(Sb‒O ), ν(W, TM‒O ) and
t
a
c
activity of four new compounds, their parent POM Na-SbW
9
,
ν(W‒O ) in SbW -TM-SnR (Fig. 5). Besides, the absorption
b
9
6
| J. Name., 2012, 00, 1-3
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bands at 1620 and 1570 cm− correspond to the pyrrole ring
ARTICLE
1
the as-obtained PPy-SbW
9
-TM-SnR/Pt composites are
View Article Online
4
0
DOI: 10.1039/C8DT05118F
stretching vibrations in PPy. Hence, IR spectra verify the
covered onto the FTO surface, and Pt micro-nano clusters
with similar diameters to that of pure Pt are incorporated
homogeneously in PPy. As illustrated in Fig. 6a–d, particles of
SbW
SEM images, which is inferred that SbW
homogeneously dispersed in PPy. Fig. 6f shows the EDS data
of PPy-SbW -Ni-SnR/Pt composite, which proves that C, N, Ni,
9
-TM-SnR (TM = Mn, Co, Ni, Zn) are not observed in the
9
-TM-SnR anions are
9
W, Pt, Sb, Sn elements are present.
The XPS spectroscopy of PPy-SbW -Co-SnR/Pt composite is
9
given in Fig. 7. As shown in Fig. 7a, the Sn 3d spectrum splits
into two peaks and their binding energies are respectively
2
2
located at 494.5 and 486.1 eV. From Fig. 7e, the two strong
peaks with binding energies of 36.9 eV and 34.8 eV,
VI
22
respectively, are ascribed to the W oxidation state. The
above results suggest that SbW -Co-SnR in the film exists in
9
its oxidized form. In Fig. 7b–c, the presence of carbon (C 1s)
and nitrogen (N 1s) are located at 284.5 and 399.6 eV in the
sample, which are derived from PPy, and the N 1s peak
4
2
observed at 399.6 eV is assigned to pyrrole nitrogen. The
peaks with binding energies of 530.3 and 531.9 eV in Fig. 7d
2
2
are attributed to O 1s. Fig. 7f–g shows XPS spectra of Pt for
PPy/Pt and PPy-SbW -Co-SnR/Pt composites, which both
have Pt 4f7/2 and Pt 4f5/2 peaks, exhibiting the presence of Pt
9
4
3
species. The XPS spectra of Pt in 4f region are decomposed
into two groups of peaks: Pt (0) and Pt(II). Significantly, the Pt
9
(0) peak for PPy-SbW -Co-SnR/Pt located at 70.58 eV (4f7/2)
and 73.93 eV (4f5/2) both shows a slightly positive shift (0.12
eV) in comparison with that for PPy/Pt located at 70.46 eV
9
Fig. 7 XPS spectra of Sn 3d (a), C 1s (b), N 1s (c), O 1s (d), W 4f (e) of PPy-SbW -Co-
SnR/Pt, Pt 4f of PPy/Pt (f) and PPy-SbW -Co-SnR/Pt (g) on FTO electrodes.
9
(
4f7/2) and 73.81 eV (4f5/2). This may be due to an interaction
4
4
9
between Pt particles and the PPy-SbW -Co-SnR support.
9
successful incorporation of SbW -TM-SnR in PPy during
electropolymerization, which can be attributed to the strong
interaction between pyrrole cations and POM anions.
Moreover, the structures of SbW -TM-SnR are stable in the
9
composites.
Besides, two peaks appearing at 539.7 and 529.78 eV
III
correspond to Sb 3d3/2 and Sb 3d5/2 of Sb center in Fig. S10
4
5
(
ESI†).
Electrocatalysis of PPy-SbW
The electrocatalytic activity of PPy-SbW
hybrids towards CH OH oxidation was determined by CV
measurements in an aqueous electrolyte solution containing
9
-TM-SnR/Pt composite films in MOR
9
-TM-SnR/Pt
Fig. 6 shows SEM images of PPy-SbW
Mn, Co, Ni, Zn) composites on FTO substrate. As shown in Fig.
e, in situ electrodeposition of pure Pt on FTO produces the
9
-TM-SnR/Pt (TM =
3
6
−1
−1
0
.5 mol L
2 4 3
H SO and 1.0 mol L CH OH (Fig. 8). As can be
sub-micron spherical particles of Pt with an average diameter
of 350 nm, and these Pt particles disperse on the surface of
seen from Fig. 8, there are two oxidation peaks located at
about 0.70 V vs Ag/AgCl during the forward scanning and
about 0.45 V vs Ag/AgCl during the reverse scanning,
FTO composed of tightly packed F-doped SnO
mass loading of Pt particles deposited on the FTO or PPy-
SbW -TM-SnR-modified FTO can be calculated using the
2
particles. The
respectively, which show a typical feature of CH
3
OH oxidation,
9
4
1
and are related to the oxidation of CH OH and intermediates,
following equation : m(Pt) = (Qdep×M) / (F×n), in which Qdep
is the charge utilized for deposition of Pt particles, M is
atomic weight of Pt, F is the faraday constant (96,485.309 C
3
4
6
3
respectively. The electrocatalytic activity towards CH OH
oxidation can be compared by the oxidation current density
that is normalized with respect to the EAS. The EAS was
estimated by the area of H-desorption of Pt catalysts
−1
mol ) and n is the electron number transferred for formation
of Pt. The mass loading of Pt is 9.45, 9.00, 12.13, 10.72, 12.18
4
7
and 10.36 µg cm−2 for Pt, PPy/Pt and PPy-SbW
(
according to the following equation (Eq. (1)):
9
-TM-SnR/Pt
TM = Mn, Co, Ni, Zn), respectively. But attention needs to be
paid that under the electrodeposition condition adopted (−
.2 V vs Ag/AgCl), hydrogen generation occurs inevitable, so
−6
2
EAS = Q
where Q
of hydrogen on the surface of Pt catalyst and a value of
H
/ (210×10 ) cm
(1)
H
(C) is the charge transferred during the desorption
0
−6
−2
2
10×10 (C cm ) is taken as the charge required for
the mass loading of Pt calculated by Coulomb charge is very
likely to be overestimated. Because of this, afterwards the
catalytic current is normalized to electroactive surface area
oxidizing a monolayer of hydrogen.
As a preliminary test, the effects of amount of both SbW -
9
Co-SnR and PPy on the electrocatalytic performance were
(EAS) of Pt. In addition, it is clearly seen from Fig. 6a–d that
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Journal Name
studied. Fig. 8a shows CV curves of PPy-SbW
hybrid electrodes prepared from different concentrations of
9
-Co-SnR/Pt
And PPy-SbW
9
-Ni-SnR/Pt shows the highest oxidation peak
View Article Online
DOI: 10.1039/C8DT05118F
current density, which is 1.85 and 1.43 times higher than
Fig. 8 CV curves that were normalized to EASs of PPy-SbW
electrode obtained from different concentrations of SbW -Co-SnR (0.5, 1.0, 3.0, 5.0
mmol L ) at scan rate of 50 mV s with Q of 4×10 C (a), obtained from different Q
9
-Co-SnR/Pt modified
9
−1
−1
-4
−
6
−5
−4
−3
−2
(
5×10 , 1×10 , 1×10 , 1×10 , 1×10 C) at scan rate of 50 mV s−1 in 1.0 mmol L−1
SbW SO OH.
9
-Co-SnR (b) in a mixed solution of 0.5 mol L−1 and 1 mol L−1 CH
H
2
4
3
SbW
9
-Co-SnR during electropolymerization of pyrrole. It can
-Co-SnR increases,
be seen that as the concentration of SbW
9
the oxidation peak current density increases thanks to more
efficiently facilitating charge transfer in the electrocatalytic
process, however, further increasing the concentration of
Fig. 9 CV curves that were normalized to EASs of different composites modified FTO
9 2 4
electrodes: Pt, PPy/Pt, PPy-SbW H SO
-TM-SnR/Pt in 0.5 mol L−1 and 1.0 mol L−1
−1
3
CH OH, scan rate is 50 mV s .
SbW
9
-Co-SnR, it leads to a decrease in the oxidation current
density, which may be because the reduction of electrical
Table 2 The detailed electrochemical parameters of various electrodes
conductivity caused by excess SbW
9
-Co-SnR. As a whole, it is
proved that 1.0 mmol L− SbW
1
9
-Co-SnR results in the highest
Sample
EAS (cm2)
(mA cm-2)
(mA cm-2)
I
f
I
b
If/Ib
current of CH
CV curves of PPy-SbW
3
OH oxidation. Furthermore, Fig. 8b displays the
-Co-SnR/Pt hybrid electrodes obtained
PPy-SbW
PPy-SbW
PPy-SbW
PPy-SbW
9
-Mn-SnR/Pt
-Co-SnR/Pt
0.84
1.27
0.83
0.84
0.77
0.80
0.81
0.87
0.84
0.61
0.18
0.27
0.19
0.17
0.25
4.40
3.03
4.55
5.09
2.42
9
from different electric quantity (Q) consumed during
electropolymerization of pyrrole, which reflects the influence
of PPy amount on the catalytic activity. It indicates that a
moderate amount of PPy can enhance the catalytic oxidation
current density, while an excessive amount of PPy reduces
the catalytic current, which may be due to the fact that
excessive PPy may inhibit the charge transmission to
electrode or inhibit the diffusion of electrolyte during the
catalytic process. Accordingly, it is clearly seen from Fig. 8b
that the composite has the biggest peak current density as
9
9
-Ni-SnR/Pt
-Zn-SnR/Pt
9
PPy/Pt
Pt
0.82
0.47
0.22
2.15
−5
the consumed electric quantity is 1×10 C.
As a consequence, under the optimized electrodeposition
−
1
condition, that is, in 1.0 mmol L SbW
9
-TM-SnR with the
consumed electric quantity of 1×10− C during potentiostatic
5
electropolymerization, four PPy-SbW
Co, Ni, Zn) hybrid electrodes were further constructed for
electrocatalytic oxidation of CH OH. Meanwhile, pure Pt and
9
-TM-SnR/Pt (TM = Mn,
3
PPy/Pt hybrid electrodes were also prepared for comparison.
CV data recorded in the potential range of ‒ 0.2 to 1.2 V (vs
Ag/AgCl) at scan rate of 50 mV s− was got to estimate the
EAS (Figs. S11 and S12, ESI†). All catalysts show the standard
hydrogen desorption potentials of ‒ 0.09 V (vs Ag/AgCl). The
1
9
associated EASs for PPy-SbW -TM-SnR/Pt (TM = Mn, Co, Ni,
9
Fig. 10 EIS of different composites modified FTO electrodes: Pt, PPy/Pt, PPy-SbW -
Zn) hybrid electrodes, PPy/Pt electrode and Pt electrode are
TM-SnR/Pt in 0.5 mol L−1
and 1.0 mol L−1 CH
2 4 3
H SO OH.
2
0
.84, 1.27, 0.83, 0.84, 0.77 and 0.82 cm , respectively. As
shown in Fig. 9, PPy-SbW
PPy-SbW -Ni-SnR/Pt and PPy-SbW
electrodes all display higher forward oxidation peak current
9
-Mn-SnR/Pt, PPy-SbW
9
-Co-SnR/Pt,
those of pure Pt and PPy/Pt electrodes, respectively. This
result proves that SbW -TM-SnR (TM = Mn, Co, Ni, Zn) can
effectively improve the electrocatalytic activity of Pt catalyst.
9
9
-Zn-SnR/Pt hybrid
9
−2
density (0.80, 0.81, 0.87, 0.84 mA cm ) than Pt electrode
−2
−2
(
0.47 mA cm ) and PPy/Pt hybrid electrode (0.61 mA cm ).
8
| J. Name., 2012, 00, 1-3
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Journal Name
ARTICLE
The four carboxyethyltin and TM co-functionalized
compounds have different electrocatalytic ability, which may
be due to their different redox property caused by TM.
characterized by electrochemical impedance spectrum (EIS)
in Fig. 10. As can be seen, the semicircle diameter is related
to the charge-transfer resistance (Rct). Compared with Pt and
View Article Online
DOI: 10.1039/C8DT05118F
PPy/Pt electrodes, PPy-SbW
which demonstrates that SbW
electron transfer process during the catalytic oxidation.
9
-TM-SnR/Pt displays smaller Rct
,
9
-TM-SnR can facilitate the
To further evaluate the electrocatalytic stability of different
films modified electrodes in MOR, chronoamperometry tests
were carried out at 0.65 V for 800 s. As shown in Fig. 11, the
current intensity of all catalysts decreases rapidly at the
beginning of the test, afterwards, it diminish much more
slowly and reach a platform within 800 s. In the beginning,
the active sites on the catalysts are occupied by intermediate
product of CH
3
OH oxidation, causing the rapid decline in
current. The subsequent slow current decrease may be due
2
−
to the adsorbed anion SO
4
4
on the surface of catalysts during
8
long time stability test. It is evident that PPy-SbW -TM-
9
SnR/Pt shows a higher quasi-stationary current and lower
decay of current with time than PPy/Pt and Pt, which
suggests a better tolerance towards CO.
Fig. 11 Chronoamperometric curves of different films modified FTO electrodes: Pt,
PPy/Pt, PPy-SbW
00 s.
9 2 4 3
H SO OH at 0.65 V for
-TM-SnR/Pt in 0.5 mol L−1 and 1.0 mol L−1 CH
8
Conclusions
Besides, the higher oxidation current density of PPy/Pt
electrode than Pt electrode is attributed to the enhancement
of conductivity by PPy. Furthermore, for comparing
In summary, four new tungstoantimonates co-functionalized
by carboxyethyltin and TM have been synthesized by
conventional method. They show good catalytic activity
towards oxidation of cyclohexanol to cyclohexanone.
Furthermore, PPy-SbW -TM-SnR/Pt composites were
9
successfully prepared through an electropolymerization
process and electrodeposition method. SEM images show
experiments, simple TM (Mn, Co, Ni, Zn) salts, Na-SbW
9
, Co-
SbW as well as Cl Sn(CH COOCH were respectively used to
9
3
)
2 2
3
construct PPy/Pt-based hybrid electrodes, and their
electrocatalytic results are shown in Figs. S13 and S14 (ESI†).
It is found that these inorganic or organic precursors do not
that PPy-SbW
and homogeneity. The electrochemical measurements
indicate that PPy-SbW -TM-SnR/Pt composites have high
electrocatalytic activity, stability and better anti-poisoning
property towards CH OH oxidation than PPy/Pt and Pt, which
is attributed to the introduction of conductivity PPy
molecules and redox activity SbW -TM-SnR, and it also
reflects a synergistic effect of PPy, SbW -TM-SnR and Pt.
These SbW -TM-SnR crystalline materials with high electron
and proton conduction ability are good redox mediators for
9
-TM-SnR/Pt composites have high dispersion
achieve the matched electrocatalytic effect like SbW
SnR, inferring that the enhancement effect of SbW -TM-SnR
is resulted from the co-functionalization of carboxyethyltin
and TM. The ratio of the forward peak current density (I ) to
the reverse anodic peak current density (I ), I /I , can be used
to describe the catalyst tolerance to carbonaceous species
accumulation. A high I /I ratio indicates that it can remove
9
-TM-
9
9
f
3
b
f b
9
f
b
9
the poisoning species more effectively from the catalyst
surface. From Table 2, it thus indicates that plenty of
intermediate carbonaceous species are oxidized to carbon
9
3
the electrochemical oxidation of CH OH.
9
dioxide for PPy-SbW -TM-SnR/Pt compared to that of PPy/Pt
or Pt in the forward scan. At the same time, the CO stripping
experiments were conducted for confirming the capability of
all the samples towards the methanol oxidation. As shown in
Conflicts of interest
There are no conflicts to declare.
Fig. S15 (ESI†), for PPy-SbW
the CO oxidation peak is observed at 0.750, 0.693, 0.737, and
.759 V vs. Ag/AgCl, respectively, and they are negatively
9
-TM-SnR/Pt (TM=Mn, Co, Ni, Zn),
0
Acknowledgements
This work was financially supported by the National Natural
Science Foundation of China (no.21671091, 21503103 and
shifted compared with the oxidation peak for Pt (0.838 V)
and PPy/Pt (0.811 V), indicating the adsorbed CO at the
surface of PPy-SbW -TM-SnR/Pt catalyst is more easily
9
removed in comparison to Pt and PPy/Pt. Besides, for all
catalysts, CO oxidation peak disappears in the second scan,
confirming the complete removal of the adsorbed CO species
from the catalyst surface.
Furthermore, the charge transfer resistance at the
interface between electrode and electrolyte was
2
1601077), and the Natural Science Foundation of Liaoning
Province (no. 20180550544).
Notes and references
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
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Pleas De ad l to o nn oT tr aa nd sj au cs t ti omn as rgins
Page 10 of 11
ARTICLE
M. E. Scofield, C. Koenigsmann, L. Wang, H. Q. Liu and S. S.
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
31 L. B. Ni, H. J. Xu, H. Li, H. X. Zhao and VGiew. AWrtic.leDOinalinoe,
Wong, Energy Environ., Sci., 2015, 8, 350–363.
Z. Chen, Y. C. He, J. H. Chen, X. Z. Fu, R. Sun, Y. X. Chen and
C. P. Wong, J. Phys. Chem. C, 2018, 122, 8976–8983.
M. Wang, X. H. Wang, J. N. Li and L. T. Liu, J. Mater. Chem.
A, 2013, 1, 8127–8133.
Polyhedron, 2018, 155, 59–65.
DOI: 10.1039/C8DT05118F
32 M. Ibrahim, S. S. Mal, B. S. Bassil, A. Banerjee and U. Kortz,
Inorg. Chem., 2011, 50, 956–960.
33 M. A. Abdellah, S. K. Hadjikakou, N. Hadjiliadis, M. Kubicki,
T. Bakas, N. Kourkoumelis, Y. V. Simos, S. Karkabounas, M.
M. Barsan and I. S. Butler, Bioinorg. Chem. Appl., 2009,
2009, 1–12.
34 J. W. Zhao, J. C. Cao, Y. Z. Li, J. Zhang and L. J. Chen, Cryst.
Growth Des., 2014, 14, 6217–6229.
35 J. P. Bai, F. Su, H. T. Zhu, H. Sun, L. C. Zhang, M. Y. Liu, W. S.
You and Z. M. Zhu, Dalton Trans., 2015, 44, 6423–6430.
36 B. Zhang, L. C. Zhang, Y. J. Zhang, F. Su, W. S. You and Z. M.
Zhu, RSC Adv., 2015, 5, 47319–47325.
37 F. M. Zonoz, Electrocatalysis, 2016, 7, 215–225.
38 J. Friedl, R. Al-Oweini, M. Herpich, B. Keita, U. Kortz and U.
Stimming, Electrochim. Acta, 2014, 141, 357–366.
39 R. Gupta, I. Khan, F. Hussain, A. M. Bossoh, I. M.
Mbomekallé, P. Oliveira, M. Sadakane, C. Kato, K. Ichihashi,
K. Inoue and S. Nishihara, Inorg. Chem., 2017, 56, 8759–
8767.
40 Y. Yuan, G. Z. Li, Y. H. Ding, K. Shilf, W. L. Zhou and J. Peng,
ChemElectroChem, 2017, 4, 1–5.
41 D. B. Gorle, V. V. Kumman and M. A. Kulandainathan, Int. J.
Hydrogen Energ., 2017, 42, 16258–16268.
42 D. P. Dubal, B. Ballesteros, A. A. Mohite and P. Gjmez-
Romero, ChemSusChem, 2017, 10, 731–737.
43 L. Ma, X. Zhao, F. Z. Si, C. P. Liu, J. H. Liao, L. L. Liang and W.
Xing, Electrochim. Acta, 2010, 55, 9105–9112.
44 Z. M. Cui, S. P. Jiang and C. M. Li, Chem. Commun., 2011,
47, 8418–8420.
45 J. C. Liu, J. Luo, Q. Han, J. Cao, L. J. Chen, Y. Song and J. W.
Zhao, J. Mater. Chem. C, 2017, 5, 2043–2055.
46 S. Gao, X. X. Yang, M. J. Wei, S. Liang, H. Y. Zang, H. Q. Tan,
Y. H. Wang and Y. G. Li, New J. Chem., 2018, 42, 198–203.
47 H. E. M. Hussein, H. Amari and J. V. Macpherson, ACS Catal.,
2017, 7, 7388–7398.
48 Z. S. Li, X. M. Huang, X. F. Zhang, L. Zhang and S. Lin, J.
Mater. Chem., 2012, 22, 23602–23607.
B. Kaur, R. Srivastava and B. Satpati, ACS Catal., 2016, 6,
2
654–2663.
X. Z. Cui, Y. Zhu, Z. L. Hua, J. W. Feng, Z. W. Liu, L. S. Chen
and J. L. Shi, Energy Environ. Sci., 2015, 8, 1261–1266.
X. Li, X. H. Niu, W. C. Zhang, Y. F. He, J. M. Pan, Y. S. Yan and
F. X. Qiu, ChemSusChem, 2017, 10, 976–983.
S. Shahrokhian and S. Rezaee, Electrochim. Acta, 2018, 259,
3
6–47.
K. Bhunia, S. Khilari, and D. Pradhan, Dalton Trans., 2017,
6, 15558-15566.
4
G. Q. Li, L. G. Feng, J. F. Chang, B. Wickman, H. Grȍnbeck, C.
P. Liu and W. Xing, ChemSusChem, 2014, 7, 3374–3381.
0 D. L. Long, R. Tsunashima and L. Cronin, Angew. Chem. Int.
Ed., 2010, 49, 1736–1758.
1 D. Xu, W. L. Chen, J. S. Li, X. J. Sang, Y. Lu, Z. M. Su and E. B.
Wang, J. Mater. Chem. A, 2015, 3, 10174–10178.
2 T. Wang, Z. Sun, F. Li and L. Xu, Electrochem. Commun.,
2
014, 47, 45–48.
3 D. Ma, L. Y. Liang, W. Chen, H. M. Liu and Y. F. Song, Adv.
Funct. Mater., 2013, 23, 6100–6105.
4 J. Friedl, M. V. Holland-Cunz, F. Cording, F. L. Pfanschilling,
C. Wills, W. McFarlane, B. Schricker, R. Fleck, H.
Wolfschmidt and U. Stimming, Energy Environ. Sci., 2018,
1
1, 3010–3018.
5 L. E. VanGelder and E. M. Matson, J. Mater. Chem. A, 2018,
, 13874–13882.
1
1
1
6
6 H. Wu, X. F. Wu, Q. G. Wu and W. F. Yan, Compos. Sci.
Technol., 2018, 162, 1–6.
7 H. Medetalibeyoğlu, S. Manap, Ȍ. A. YokuŞ, M. Beytur, F.
KardaŞ, O. Akyıldırım, Vildan Ȍ zkan, H. Yȕksek, M. L. Yola
and N. Atar, J. Electrochem. Soc., 2018, 165, 338–341.
8 H. l. Shi, R. Y. Wang, M. G. Lou, D. Z. Jia, Y. Guo, X. C.Wang,
Y. D. Huang, Z. P. Sun, T. Wang and L. X. Wang, Electrochim.
Acta, 2019, 294, 93–101.
1
1
2
2
9 X. He, L. Chen, Z. Li, X. Zhang, A. Ma and S. Lin, Fuell Cells,
2
015, 15, 221–229.
0 Y. P. Liu, S. F. Zhao, S. X. Guo, A. M. Bond and J. Zhang, J.
Am. Chem. Soc., 2016, 138, 2617–2628.
1 X. J. Sang, J. S. Li, L. C. Zhang, Z. J. Wang, W. L. Chen, Z. M.
Zhu, Z. M. Su and E. B. Wang, ACS Appl. Mater. Interfaces,
2
014, 6, 7876–7884.
2
2 L. Y Guo, Y. Li, Y. Zhang, J. S. Li, W. S. You, F. Su, Z. M. Zhu,
X. J. Sang and L. C. Zhang, RSC Adv., 2017, 7, 20685–20693.
3 X. J. Sang, J. S. Li, L. C. Zhang, Z. M. Zhu, W. L. Chen, Y. G. Li,
Z. M. Su and E. B. Wang, Chem. Commun., 2014, 50, 14678–
2
1
4681.
2
2
2
4 L. C. Zhang, S. L. Zheng, H. Xue, Z. M. Zhu, W. S. You, Y. G. Li
and E. B. Wang, Dalton Trans., 2010, 39, 3369–3371.
5 L. P. Ji, J. Du, J. S. Li, L. C. Zhang, X. J. Sang, H. Yang, H. J. Cui
and Z. M. Zhu, RSC Adv., 2016, 6, 28956–28959.
6 H. Sun, L. Y. Guo, J. S. Li, J. P. Bai, F. Su, L. C. Zhang, X. J.
Sang, W. S. You and Z. M. Zhu, ChemSusChem, 2016, 9,
1
125–1133.
7 R. E. Hutton, J. W. Burley, J. Organomet. Chem., 1978, 156,
69–382.
8 M. Bȍsing, I. Loose, H. Pohlmann and B. Krebs, Chem. Eur. J.,
2
2
3
1
997, 3, 1232–1237.
2
3
9 G. M. Sheldrick, Acta Cryst., 2015, C71, 3–8.
0 (a) H. Yang, L. C. Zhang, L. Yang, X. L. Zhang, W. S. You and Z.
M. Zhu, Inorg. Chem. Commun., 2013, 29, 33–36; (b) S. L.
Feng, Y. Lu, Y. X. Zhang, F. Su, X. J. Sang, L. C. Zhang, W. S.
You and Z. M. Zhu, Dalton Trans., 2018, 47, 14060–14069.
1
0 | J. Name., 2012, 00, 1-3
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Page 11 of 11
Dalton Transactions
View Article Online
DOI: 10.1039/C8DT05118F
Carboxyethyltin and transition metal co-functionalized
tungstoantimonates composited with polypyrrole for enhanced
electrocatalytic methanol oxidation
a
a
a
a
a
Hai-Dan Wang, Xing-Fang Wang, Fang Su, Jian-Sheng Li, Lan-Cui Zhang,* Xiao-Jing
a
a
Sang,* Zai-Ming Zhu*
Graphic Abstract
PPy-SbW -TM-SnR/Pt-based electrocatalysts (TM = Mn, Co, Ni, Zn) were synthesized by
9
electro-deposition method and showed good performance of methanol oxidation reaction.