Precursor-mediated synthesis of Cu2-xSe nanoparticles and their composites with TiO2 for improved photocatalysis

Article abstract of DOI:10.1039/c8dt01625a

The direct synthesis of copper selenide nanoparticles from the reaction of ditertiarybutyl selenide ^tBu₂Se with copper(ii) trifluoroacetate Cu(TFA)₂ under mild conditions is reported. The isolation of a molecular species d

Full text of DOI:10.1039/c8dt01625a

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PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
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ARTICLE TYPE
Precursor-mediated synthesis of Cu Se nanoparticles and its
2
-x
composites with TiO for improved photocatalysis†
2
a
b
a
a
a
Sweta Gahlot, Erwann Jeanneau, Frederic Dappozze, Chantal Guillard, and Shashank Mishra*
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
5
DOI: 10.1039/b000000x
t
Direct synthesis of copper selenide nanoparticles from the reaction of ditertiarybutyl selenide Bu Se with
2
copper(II) trifluoroacetate Cu(TFA) under mild conditions is reported. Isolation of a molecular species
2
t
during the course of this reaction, established as [Cu (TFA) ( Bu Se) ] by spectroscopic studies and single
2
2
2
3
crystal Xꢀray structure, confirmed that metal selenide NPs are formed via this intermediate species
1
0
containing reduced copper center. Extending this reaction in the presence of commercial TiO (P25)
2
offered an easy synthesis of copper selenideꢀtitania nanocomposites with different Cu/Ti ratios. These
nanocomposites, wellꢀcharacterized by powder XRD, STEM, TEM, BET, XPS, EDX and UVꢀVis
studies, were examined as photocatalysts for the degradation of formic acid (FA). The nCu2ꢀxSeꢀTiO2
nanocomposites with low mol% of copper selenide i.e., n = 0.1 and 0.3 mol%, displayed a superior
catalytic activity over P25, which is an established benchmark for the photocatalysis under UV light.
1
5
multiple structural forms such as tetragonal umangite (Cu Se ),
3
2
Introduction
cubic berzelianite (Cu
Se, Cu1.8Se), orthorhombic marcasite
2
(
CuSe ), orthorhombic athabascaite (Cu Se ) and hexagonal
2
5
4
Excellent physical and chemical properties of wellꢀknown
semiconducting photocatalyst TiO make it stand out from the
other photocatalysts. However, its low photonic efficiency in the
visible region and fast recombination of a large population of
photo generated electronꢀhole pairs are major limitations for its
application in photocatalytic process. Among many strategies to
improve the photocatalytic efficiency of TiO , a majority of
which includes introduction of metallic or nonꢀmetallic impurity
inside to modify its electronic structure, one effective method is
to combine it with another low bandgap semiconducting materials
to extend its absorption spectrum and to sensitize it for UVꢀvisꢀ
9
5
0
klockmannite (CuSe, Cu0.87Se). In addition, its atomic
rearrangement in binary nonꢀstoichiometric Cu2−xSe is quite
complex, and a wide variety of crystal phases with diverse
2
2
2
3
3
4
4
0
5
0
5
0
5
10
defects exist. Cu2ꢀxSe crystals show high conversion efficiency
as their bandgaps lie in the range of 1.4ꢀ2.2 eV. Several chemical
routes have been employed for the synthesis of controlled
morphologies of copper selenide nanostructures with size ranging
1
55
2
10ꢀ16
in a broad spectrum.
These include i) solvothermal process
using either sodium selenite/copper acetate/ethylene glycolꢀ
10
11
water, or Se powder/Cu foil/hexanol, ii) hydrothermal method
12
2
60 using ionic liquid as selenium source, iii) template method using
driven photocatalysis. Some examples of metalꢀchalcogenide
13
3
preformed CuO, iv) redox reaction using copper sulphate/Se
based semiconducting materials used for this purpose are CdS,
14
4
5
6
7
NPs/polystyrene sulfonate, v) oneꢀpot synthsis using copper
stearate/Se–octadecene/oleic acidꢀoleylamine,
injection method using CuCl/Ph Se /1ꢀoctadeceneꢀoleylamine.
CdSe, CdSeTe, Ag S, and Ag Se. An earlier work from this
2
2
15
and vi) hot
laboratory has shown a ‘bottomꢀup’ synthesis of Ag SeꢀTiO2
nanocomposites which exhibited better catalytic activity as
compared to the commercially available TiO (P25). Though an
improved photocatalyst, the composite Ag SeꢀTiO suffered a
drawback of being photosensitive in nature that caused the
degradation of Ag Se to Ag nanoparticles on prolonged exposure
to light. Further, silver raises concerns over its adverse effects on
health and environment. These limitations, coupled with silver’s
high costs, prompted us to consider copper selenide as an
efficient alternative to above nanocomposites. To the best of our
knowledge, there is no report on the photocatalysis of Cu2ꢀxSeꢀ
TiO2 composites, though Chen et al. recently reported the
2
1
6
2
2
7
65 Bottomꢀup synthesis of nanomaterials using wellꢀdefined
molecular precursors offers numerous advantages over other
2
2
2
17
synthetic routes. However, thoroughly characterized single
source precursors (SSPs) for copper selenide nanomaterials are
limited and a majority of them require high temperatures for their
2
18
70
conversion into nanomaterials. Recently, selenoethers have
emerged as simple yet effective sources of producing seleniumꢀ
containing chalcopyrite semiconducting materials.
researchers have used metal complexes with selenoethers as
single source precursors, while others have employed the
1
9,20
Several
19
t
preparation of complex Cu SeꢀCdSeꢀTiO composites which 75 reactions of selenoethers R Se (R= Me, Et, Bu) with metal
2
2
2
showed many fold enhancement in photocurrent density as
compared to pure TiO2.
Copper selenide is a pꢀtype semiconductor which exists in
halides, metal oxohalides and metal alkyls in chemical vapor
deposition (CVD) technique to derive highꢀquality metal solenoid
films. With an aim to develop new and effective precursors for
8
20
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copper selenide nanomaterials, we studied the reactions of
nm) radiation at 50 kV and 35 mA to measure the Xꢀray
selenoether with different copper reagents. While the reaction of 60 diffraction (XRD) patterns of the powdered crystals. The
t
ditertiarybutyl selenide Bu Se with Cu(TFA)2 (TFA
=
absorbance characteristics of the nanocomposites were measured
using a UVꢀvis spectrophotometer (AvaSpec Avantes Fiber Optic
Spectrometer systems). The nitrogen adsorption and desorption
isotherms were measured on an ASAP 2020 system. We
2
trifluoroacetate) in various solvents resulted in the formation of
Cu2ꢀxSe NPs under mild conditions, its reaction with CuI led to
5
0
5
0
5
0
5
0
5
0
5
t
isolation of
a
stable molecular complex [Cu I ( Bu Se) ].
4
4
2
4
Successful isolation of a molecular species in the former case, 65 employed the linear part of BrunauerꢀEmmettꢀTeller (BET)
t
established as [Cu (TFA) ( Bu Se) ] by spectroscopic studies and
method to calculate the specific surface area of these
nanocomposites, while BarrettꢀJoynerꢀHalenda (BJH) method
provided their pore size distribution. An electron spectrometer
(Kratos Axis Ultra DLD) with an Al Kα (1486.6 eV) radiation
2
2
2
3
single crystal Xꢀray structure, confirmed that copper selenide NPs
are formed via this intermediate species containing reduced
copper center. Although several families of molecular precursors
1
1
2
2
3
3
4
4
5
5
2
1
are known for metal chalcogenide nanomaterials, except for one 70 source was used to perform the Xꢀray photoelectron spectroscopy
7
publication from our group, there is no report available in the
literature on the use of selenoether ligand in Chemical Solution
Deposition (CSD) of metal selenides. The compounds reported
here assume importance because not only they satisfy the general
(XPS) analysis of the catalysts. Corrections on the constant
charging of the XPS spectra were made by C 1s of adventitious
carbon (binding energy of 284.6 eV).
criteria of CSD precursors such as easy preparation, good 75 Synthesis of copper complexes and Cu2-xSe nanoparticles
solubility in organic solvents, and facile and clean decomposition
t
t
but also highlight the dual role of the selenoether i.e., a facile
source of selenium and a reducing reagent to get desirable +1
oxidation state of the copper center. Equally important is the fact
[Cu (TFA) ( Bu Se) ] (1). Bu Se (0.062 mL, 0.32 mmol) was
2 2 2 3 2
added dropwise to the blue colored solution of Cu(TFA) (0.1 g,
0.32 mmol). After stirring the solution for 15 minutes at room
2
that a wellꢀdefined chemical route for the formation of copper 80 temperature, the solution was concentrated under vacuum and
selenide nanoparticles is unequivocally established here by the
isolation and complete characterization of the intermediate
layered with nꢀpentane to obtain colorless crystals of 1. Crystals
were isolated after removing the mother liquor through cannula,
followed by subsequent washing with cold nꢀpentane. Yield, 1.0
t
[Cu (TFA) ( Bu Se) ]. After thoroughly characterizing the
2
2
2
3
ꢀ
1
intermediate and final complexes and stablishing the route for
their conversion to nanoparticles, we proceeded further to obtain 85 1685s, 1461s, 1370s, 1207s, 1143s, 1017m, 926w, 835s, 790m,
copper selenideꢀtitania nanocomposites that showed an improved
g (60%). FTꢀIR (nujol, cm ): 3120w, 3075w, 2722w, 2376w,
1
718s, 609w, 527m. H NMR (CDCl , 23°C, ppm): δ 1.58.
3
photocatalytic activity over the commercial TiO (P25) for the
degradation of formic acid (FA) solution on UV irradiation. The
photodegradation of formic acid was selected as a model
2
t
[Cu I ( Bu Se) ] (2). A dichloromethane solution containg CuI
4
4
2
4
t
(0.1 g, 0.52 mmol) and Bu Se (0.15 mL, 0.78 mmol) was stirred
2
reaction because not only it is converted to CO and H O 90 at room temperature for 1 hour. Colorless crystals of 2 were
2
2
without the formation of any stable intermediate species, but
the reaction also represents possible final step in the
photodegradation of more complex organic compounds. The
P25 is considered a benchmark for photocatalytic reactions under
obtained from the concentrated solution at –10 °C. The
crystallized product was isolated after removing the mother
solution through cannula, followed by subsequent washing with
a
22
cold nꢀpentane. Yield, 0.16
g (78%). Anal.: calcd for
UVꢀlights, and only a few studies have reported a superior 95 C H Cu I Se (1534.4): C, 25.0, H, 4.69; found: C, 24.4, H,
3
2
72
4 4
4
−1
photocatalytic activity.
4.61%. FTꢀIR (nujol, cm ): 2990sꢀ2860s, 1472s, 1400m, 1390s,
364s, 1210m, 1155s, 1025m, 930w, 810, 610w. H NMR
1
1
Experimental
(CDCl , 23°C, ppm): δ 1.55.
3
General Procedures. Except for photocatalysis, which was 100 Cu2-xSe nanoparticles. We optimized the conditions for the
carried under ambient atmosphere, all other manipulations were
performed under the argon atmosphere using standard Schlenk
and glovebox techniques. Solvents were dried using MB SPSꢀ800
and used without further purification. Copper(II) trifluoroacetate
preparation of Cu2ꢀxSe NPs by varying the reactants, solvents,
temperature and stirring/refluxing time of the reactions (vide
infra, results & discussion section). Stirring of a reaction mixture
t
containing Cu(TFA) (0.12 g, 0.34 mmol) and Bu Se (0.04 mL,
2
2
and copper(I) iodide (both Aldrich), diꢀtertiaryꢀbutylselenide 105 0.20 mmol) in Et O (20 mL) led to gradual change of the color of
2
t
Bu Se (SAFC Hitech), TiO (P25, Evonik, exꢀDegussa) and
the solution, from blue to green and then brown. Further stirring
of this reaction mixture for 24 h afforded black coloured
nanoparticles of Cu2ꢀxSe. The reaction time could be reduced to 3
2
2
formic acid (99%, Acros Organics) were purchased and used
without further purification. H NMR spectra were recorded in
1
CDCl on a Bruker ACꢀ300 spectrometer. The infrared spectra
were obtained as Nujol mulls on a Bruker Vector 22 FTꢀIR 110 Cu(TFA) (0.1 g, 0.28 mmol) and Bu Se (0.03 mL, 0.17 mmol)
hours by refluxing the THF (30 mL) solution containing
3
t
2
2
spectrometer at room temperature and registered from 4000 to
at 65 °C, though the yield was quite poor (~10%). The yield of
Cu2ꢀxSe NPs, however, could be enhanced significantly up to
94% by substituting the solvent THF with toluene and refluxing
the mixture at 115 °C for 3 h.
−1
4
00 cm . The scanning electron microscopy (SEM)
measurements were performed on Hitachi S800. TEM
experiments were performed using a JEMꢀ2100F with 200kV
field emission (FE) and JEOL 2010 LaB6 with 200kV FE. We 115
used a Bruker D8 Advance A25 with Cu Kα1+2 (λ=0.154184
Preparation of n% Cu2-xSe-TiO nanocomposites
2
2
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0
.1%Cu2-xSe-TiO . Cu(TFA) (0.006 g, 0.017 mmol) was stirred
2 2
in toluene (20 mL) for 15 min to get a transparent light blue
solution. After adding TiO (P25) (0.7 g, 8.76 mmol) and stirring
2
t
5
0
5
0
5
0
5
0
5
0
5
the reaction mixture for 15 min, an excess of Bu Se was added
2
dropwise. The obtained mixture was refluxed for 3 h after which
an offꢀwhite powder was isolated by centrifugation. The powder
was then washed with ethanol several times and dried at room
temperature.
1
1
2
2
3
3
4
4
5
5
Using above method, 0.3%Cu2ꢀxSeꢀTiO and 1% Cu2ꢀxSe,ꢀTiO2
2
nanocomposites were also synthesized using appropriate ratios of
t
Cu(TFA) , Bu Se and TiO .
2
2
2
Figure 1. XRD pattern of Cu2ꢀxSe NPs obtained from the reaction of Cu(TFA)
2
and
Formic Acid Photodegradation. Nanocomposite powder (30
mg) was dispersed in 30 mL aqueous solution of 50 ppm formic
acid. The suspension was magnetically stirred for 30 min in the
dark to obtain a complete adsorptionꢀdesorption equilibrium. It
was then irradiated with UVꢀVis lamp (HPK 125 W highꢀ
pressure mercury vapor lamp). A cutoff filter with λ > 350 nm
placed in a water cuvette situated beneath the reactor was used to
perform the photocatalytic degradations of FA. The cutoff filter
allows the use of wavelength at 365 nm only. We measured the
radiant flux using a VLXꢀ3W radiometer with a CXꢀ365 detector
t
Bu
2
Se in toluene under refluxing condition.
ꢀ3
ꢀ3
t
ꢁ
ρmax = 2.38 e.Å , ꢁρ = ꢀ1.89 e.Å . [Cu I ( Bu Se) ] (2): Mr
min 4 4 2 4
6
0
= 1534.5, Monoclinic, Cc, a = 14.7484(4) Å, b = 14.7713(3) Å, c
22.8613(7) Å, β = 97.390(3)°, V = 4939.0(2) ų, Z = 4, µ =
=
ꢀ1
7
.17 mm , T = 150 K, 21683 Measured reflections, 10065
Independent reflections, Rint = 0.069, 9995 no. of reflections, 274
2
2
restraints, 398 parameters, S = 0.97, R[(F > 2σ (F )] = 0.113,
2
ꢀ3
ꢀ3
65
wR(F ) = 0.237, ꢁρ = 4.50 e.Å , ꢁρ = ꢀ2.74 e.Å .
max min
(UVꢀA). The distance between the photoreactor and the water cell
Results and discussions
was controlled to maintain the radiant flux fixed at 4.1 ± 0.2
t
ꢀ
2
(
a) Divergent reactivity of Bu Se with copper reagents:
mWcm for all photocatalytic tests. The concentration of formic
acid was determined by HPLC, with VARIAN Star Series, with
ICE COREGEL 87ꢀH3 (300x7.8mm), a Starꢀ230 pump, a Starꢀ
2
Formation of Cu2-xSe nanoparticles vs. molecular complex
Extending our previous work on the reactivity of selenoethers
7
t
7
7
8
8
9
9
0
5
0
5
0
5
with silver(I) reagent, we studied here the reactions of Bu Se
2
3
25 UVꢀVis detector detecting at 210nm and a Starꢀ410
ꢀ
3
with two different copper reagents i.e., Cu(TFA) (where TFA =
autosampler. The mobile phase consisted of 5x10 mol/L of
H SO (pH2) with a flow rate of 0.7 ml/min, while the Column
2
trifluoroacetate) and CuI in different solvents. The aim was to
exploit the divergent reactivity of above selenoether to obtain
2
4
thermostat is set at 30 °C. Photodegradation under visible light
was performed using visible LED (white light) lamps
manufactured by Macrolenses (Germany). After stirring in the
dark for 30 min, a 30 mL FA (50 ppm) solution containing 30 mg
of catalyst was irradiated under visible light for 3 h.
copper selenide nanomaterials and its composites with TiO for
2
t
photocatalytic applications. Addition of Bu Se to Cu(TFA) at
2
2
room temperature in
a variety of solvents (diethylether,
tetrahydrofuran or toluene) led to gradual change in color of the
solution from blue to green and finally precipitation of a black
colored copper selenide powder, as determined by powder Xꢀray
diffraction studies (Fig. S1). However, reactions at room
temperature were not very reproducible in terms of yield and time
needed for precipitation (varied from few hours to one or two
days) and sometimes, there were unrecognised impurities (extra
peaks in XRD which we could not index). However, by
performing the reactions under refluxing conditions, we not only
reduced the reaction time significantly, but also made it
reproducible in terms of products obtained. Thus, the color of the
THF solution, on refluxing at 65 °C, changed from dark green to
brown and then to black to give finally black precipitate after 3
hours (albeit in low yield of 10%). The powder XRD of this
precipitate indicated it to be a mixture of two phases of copper
selenide Cu1.82Se (01ꢀ071ꢀ6180) and and Cu Se (00ꢀ047ꢀ1745)
X-Ray Crystallography. Suitable crystals of 1 and 2 were
obtained as described in the synthetic procedure. Crystal structure
were measured using Mo radiation (λ = 0.71073 Å) on an Oxford
Diffraction Gemini diffractometer equipped with an Atlas CCD
detector. Intensities were collected at 100 K by means of the
2
3
CrysalisPro software. Reflection indexing, unitꢀcell parameters
refinement, Lorentzꢀpolarization correction, peak integration and
background determination were carried out with the CrysalisPro
23
software. An analytical absorption correction was applied using
2
4
the modeled faces of the crystal. The resulting sets of hkl were
used for structure solutions and refinements. The structures were
2
5
solved by direct methods with SIR97 and the leastꢀsquare
26
refinement on F2 was achieved with the CRYSTALS software.
3
2
t
(Fig. S2). We succeeded to increasing the yield of nanoparticles
Crystallographic and refinement data. [Cu (TFA) ( Bu Se) ]
2
2
2
3
significantly by taking toluene as a solvent and refluxing the
reaction mixture at a raised temperature of 115 °C. These reaction
conditions were reproducible which always led to the formation
(
1
1): Mr = 932.69, Triclinic, P-1, a = 12.0827(6) Å, b =
6.2379(9) Å, c = 20.2592(10) Å, α = 91.486(4)°, β = 92.316(4)°,
ꢀ
1
γ = 104.996(5)°, V = 3833.6(4) ų, Z = 4, µ = 4.02 mm , T = 150
K, 69037 Measured reflections, 19642 Independent reflections,
Rint = 0.056, 19600 no. of reflections, 63 restraints, 775
of Cu1.82Se as a major phase (in addition to Cu Se as a minor
3
2
phase) (Fig. 1). Refluxing in toluene, however, increased the
average size of nanoparticles to 55 nm from 20 nm as determined
2
2
2
parameters, S = 1.01, R[(F > 2σ (F )] = 0.072, wR(F ) = 0.150,
100 using the Debye–Scherrer formula. The SEM images show
This journal is © The Royal Society of Chemistry [year]
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Figure 3. Perspective view of the molecular structures of 2 with 50% probability
ellipsoids. H atoms on alkyl group are omitted for clarity. Selected bond lengths (Å)
and angles (°): I1—Cu1 2.783(4), I1— Cu2 2.728(3), I2— Cu1 2.706(4), Cu1•••Cu2
2
2
.997(4), Cu1•••Cu4 3.287(4), Cu3ꢃꢃꢃCu4 3.001(4), Cu1—Se1 2.452(4), Cu2—Se2
.470(5), I1—Cu1—Se1 102.3(1), I1—Cu1—I3 100.9(1), I2— Cu3—I4 104.8(1).
t
2
3
3
4
4
5
5
6
5
0
5
0
5
0
5
0
solvents (THF, toluene, hexane). The high reactivity of Bu Se to
2
give directly metal selenide nanoparticles could be attributed to
availability of a decomposition path via βꢀhydrogen elimination
as well as a weaker CꢀSe bond in this ligand. Among copper
reagents used here, the trifluoroacetate (TFA) ligand appears to
be more labile than the iodide ligand. Such a trend was observed
28
7,29
previously also.
It is pertinent to note that only few wellꢀ
characterized coordination complexes of copper with the neutral
30
selenideꢀcontaining ligands exist in the literature.
t
Figure 2. Characterization of the intermediate species [Cu
2
(TFA)
2
( Bu
2
Se)
3
] (1). (a)
The FTꢀIR spectra of 1 and 2 show characteristic bands for the
ligand Bu Se, the former complex also showing additional bands
for the trifluoroacetate ligand (Fig. 2a). Presence of only one
strong band due to ν CO at 1685 cm is consistent with the fact
as 2
that there is only one bonding mode of the TFA ligands in 1 (Fig.
c). Other characteristic absorptions due to νCꢀF and νCꢀO of the
TFA ligand as well as νCu–O vibrations are observed in the
expected region. The H NMR spectra of 1 and 2 in CDCl are
simple and show only a singlet at δ = 1.55–1.58 ppm for the Bu
group of the selenoether (Fig. 2b). Complex 1 crystallizes in the
triclinic space group P-1 (with R = 0.072 and wR = 0.150) and
has two independent molecules in the asymmetric unit. Each
molecule adopts a discrete dinuclear structure, where two
copper(I) centers having a short cuperophilic interaction (Cu•••Cu
3.408(1)ꢀ3.417(1) Å) are further bridged by one µꢀ Bu Se and
2
two ꢂꢀη :η ꢀTFA ligands (Fig. 2c). One terminal Bu Se on each
copper atom then complete the pseudoꢀtetrahedral geometry
around it (if Cu•••Cu interaction is not taken into account), as
indicated by the OꢀCuꢀO, SeꢀCuꢀSe and SeꢀCuꢀO angles, which
lie in the range 95.0(3)–124.6(5). The CuꢀµꢀSe bond distances
1
FTꢀIR spectrum, (b) H NMR spectrum, and (c) perspective view of the molecular
structure with 50% probability ellipsoids (H atoms omitted for clarity). Selected bond
lengths (Å) and angles (°): Cu1—O1 2.061(6), Cu1—O3 2.078(6), Cu2—O2
t
2
ꢀ
1
2
2
.065(6), Cu1—Se1 2.437(1), Cu2—Se1 2.432(1), Cu1—Se2 2.365(1), Cu2—Se3
.360(1), Cu1•••Cu2 3.408(1), O1—Cu1—O3 95.0(3), Se1—Cu1—O3 100.8(2),
Se2—Cu1—O3 115.3(2), Cu1—Cu2—Se3 168.3(5).
2
significant aggregation of these particles (Fig. S3), which is not
surprising given that the synthesis was achieved in the absence of
31
1
3
t
any capping ligand. The gradual change in the color of Cu(TFA)2
t
solution on adding Bu Se suggested that the copper selenide
2
5
0
5
0
nanoparticles are formed via the reduction of copper(II) species.
Therefore, attempts were made to characterize the species present
in the solution before the precipitation of Cu2ꢀxSe NPs. We
succeeded in isolating an intermediate molecular species
32
t
=
t
[
Cu (TFA) ( Bu Se) ] (1) from the reaction mixture and
2
2
2
3
1
1
t
2
1
1
2
characterising it by spectroscopic and single crystal Xꢀray
diffraction studies (Fig. 2), which showed that the copper center
in this complex are in +1 oxidation state (vide infra). The ability
of selenoethers to reduce metal centers has previously been
27
demonstrated. In contrast to above obervation, the reaction of
[
2.431(1)ꢀ2.437(1) Å] are longer than the terminal CuꢀSe ones
[2.359(1)ꢀ2.374(1) Å]. Such a trend has been observed previously
also in the related copper halide clusters with thioethers. The
Cu–O bond lengths, 2.052(6)ꢀ2.079(6) Å, for bridging
trifluoroacetate ligand compare well with the literature values.
The tetrameric structure of [Cu I ( Bu Se) ] (2), which
crystallizes in the monoclinic space group Cc (with R = 0.113 and
wR = 0.237), is similar to that reported for its silver analogue. It
t
Bu Se with copper iodide in dichloromethane was straight
2
forward, which led to the isolation of a stable molecular complex
3
3
t
[
Cu I ( Bu Se) ] (2). Unlike the intermediate derivative 1, which
4
4
2
4
turns gradually black even when kept in dark at low temperature
and under inert atmosphere, apparently due to the formation of
Cu2ꢀxSe NPs, complex 2 is stable at rt. Fortunately, the
intermediate 1 was stable for sufficiently long time to allow its
complete characterization. This complex is also more soluble in
common organic solvent as compared to 2 which is soluble in
dichloromethane but shows limited to poor solubility in other
34
t
4
4
2
4
7
presents a cubane geometry formed by four copper and four
iodine atoms, which alternatively occupy the corners of a
t
distorted cube, with the Bu Se ligands coordinated to the copper
2
4
| Journal Name, [year], [vol], 00–00
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DOI: 10.1039/C8DT01625A
a)
Figure 5. XPS spectra showing wide scan spectrum (a) and binding energies of Cu2p
(b) and Se3d (c).
provides the surface areas, total pore volumes, and average pore
diameters. We measured the band gap of the nCu2ꢀxSeꢀTiO2
nanocomposites (having different Cu/Ti ratios) through Kubelka
30
munk plots as shown in Fig. 4b. TiO shows the characteristic
2
spectrum indicating a band gap of about 3.2 eV. However, as
mol% of Cu2ꢀxSe increased, the band edge was redꢀshifted
b)
Figure 4. BET isotherms (a) and Kubelka munk plots (b) of P25 and Cu2ꢀxSeꢀTiO
nanocomposites with different % of Cu2ꢀxSe.
2
35 considerably (band gap in the region 3.1ꢀ2.9 eV) (Fig. S6). The
increase in absorption is attributed to the narrow band gap of Cu2ꢀ
xSe NPs. With an increased absorption in the visible wavelength,
more electronꢀhole pairs are expected to be generated in the
composite under UVꢀVisible light. To further confirm the
atoms (Fig. 3). Each face is distorted due to cuperophillic CuꢃꢃꢃCu
3
2
interactions [2.997(4)ꢀ3.287(4) Å]. The CuꢀI [2.706(4)ꢀ2.805(4)
Å] and CuꢀSe [2.452(4)ꢀ2.470(5) Å] bond lengths in 2 are 40 composition and valence state of these nanocomposites, Xꢀray
consistent with the literature value on related copper systems with
photoelectron spectroscopy (XPS) studies were conducted on a
representative sample Cu2−xSeꢀTiO2 with a copper selenide
loading content of 1mol%. As shown in Fig. 5a, the wide scan
spectrum indicates that this sample consists of the elements Ti,
5
0
5
0
5
bridging iodide and terminal bonded selenium containing
35
ligands. These cubanes are discrete entity and have no
intermolecular interaction among them. This is different from the
previously reported copper halide clusters with thioethers where 45 Cu, Se, O, C and F, the presence of the last element could be
cubaneꢀlike clusters [Cu I (Et S) ] act as secondary building units
attributed to the use of copper trifluoroacetate as a starting
reagent. The signal due to fluoride contamination, however,
disappears in the recycled catalyst, indicating that the fluoride
ions are adsorbed on the surface only. In the core level spectrum
4
4
2
4
3
3
1
1
2
2
to give 1D coordination polymer.
b) Preparation and characterization of Cu2-xSe-TiO2
nanocomposites
(
We prepared nCu2ꢀxSeꢀTiO nanocomposites with different Cu/Ti 50 of the Ti 2p region, binding energies at 458.4 eV and 464.3 eV,
2
ratios (n = 0.1, 0.3 and 1 mol%) by refluxing Cu(TFA) and
corresponding to Ti 2p3/2 and Ti 2p1/2, respectively, indicate the
2
t
Bu Se in toluene with different amounts of commercial TiO ꢀ
presence of Ti(IV) in the form of TiO . The O 1s peak observed
2
2
2
P25. After general workup, the precipitated offꢀwhite powders
were isolated through centrifugation, washed with ethanol and
at 529.6 eV is attributed to the TiꢀOꢀTi bond, thus supporting the
6
presence of TiO . The observed peaks for Cu 2p and Cu 2p1/2
2
3/2
left to dry at room temperature for 24h (schematic representation 55 at 933 eV and 953 eV, respectively, and the lack of satellite peaks
3
6
in Fig. S4). Because of the low percentage of copper selenide
indicate the presence of copper in +1 oxidation state (Fig. 5b).
content in these nanocomposites, their XRD patterns showed
The Se 3d spectrum is deconvoluted to show the presence of two
majorly the characteristic peaks of the commercial TiO (P25)
wellꢀresolved doublets (Fig. 5c), the major peak located at 52.3
eV and corresponding to Se 3d5/2, indicates Se , though a very
2
2ꢀ 37
[00ꢀ021ꢀ1272 (anatase) and 01ꢀ079ꢀ6029 (rutile) (Fig. S5). The
surface characteristic of the commercial P25 and nCu2ꢀxSeꢀTiO2 60 small contribution due to metallic selenium is also observed at
nanocomposites were studied by BrunauerꢀEmmettꢀTeller (BET)
measurements (Fig. 4a). The obtained isotherms are identified as
type IV having small hysteresis loop in a relative pressure of
about 50 eV. The presence of trace amount of metallic selenium
in the precursorꢀdirected synthesis was observed previously also.
We are currently working on to address it by varying the
7
0
.85ꢀ1.00. Compared to the pure TiO , the nanocomposites
2
experimental conditions. The microstructures and the
showed a slight decrease in the BET surface area. Table S1 65 morphology of this representative composite were further studied
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DOI: 10.1039/C8DT01625A
Figure 7. Photodegradation of FA using TiO
of Cu2ꢀxSe under UV light.
2
, Cu2ꢀxSe and Cu2ꢀxSeꢀTiO
▪
2
with different
%
▪ꢀ
+
O2 combines with H to generate HO2 (eqn S5ꢀ6 in the
Supporting Information). Previous studies have reported the twoꢀ
step catalytic degradation of formic acid: first to formate and then
2
Figure 6. TEM and HRꢀTEM images of 1% Cu2ꢀxSeꢀTiO nanocomposite at different
resolution (aꢀc). Fig. 5d shows selected area diffraction pattern of Cu2ꢀxSe NPs.
4
4
5
5
6
6
0
5
0
5
0
5
40
to CO2. The composite with 1% Cu2ꢀxSe content, however,
showed reduced activity. We can corelate this to the fact that a
high content of copper selenide darkens the sample, which leads
to an insufficient usage of UV radiations and a lower number of
electronꢀhole pairs. An initial attempt to degrade FA using Cu2ꢀ
SeꢀTiO nanocomposites under visible light was ineffective, and
by STEM and HRꢀTEM studies (Fig. 6, S7 and S8). While STEM
images indicated intimate mixing of the TiO2 and Cu2ꢀxSe
components, the EDX spectra confirmed the presence of Cu and
Se contents in the nanocomposite (Fig. S7). The HRTEM images
shown in Figure 6 and S8 reveal different orientations and
5
x
2
interplanar spacing and show lattice fringes for TiO and Cu2ꢀxSe
2
no activity was observed (Figure S11). Even though the band gap
for the composites reported here is reduced and visible light
absorption is improved, it may not be enough to bring the
changes for the visible lamp we used (which emits photons only
after 410 nm). It is also quite possible that the absorbed photons
are used for some other reactions such as producing heat or
contents. In particular, an interplanar distance of 0.209 nm could
be attributed to the (202) plane of Cu2ꢀxSe, as also confirmed by
the selected area diffraction pattern (Fig. 6d).
1
0
c) Photocatalysis
Using the Cu2ꢀxSeꢀTiO2 nanocomposites as photocatalysts, we
performed photodegradation studies on FA solution under UV
and visible light by monitoring with HPLC. Figure S9 presents
the experimental setting for the photocatalytic degradation of FA,
where a 100 mL photoreactor was used. All samples were stirred
for 30 minutes in dark to reach the adsorptionꢀdesorption
equilibrium. While no significant difference in the adsorption of
formic acid was observed, the nanocomposite samples with 0.1%
and 0.3mol% of copper selenide exhibited enhanced
ꢀ
+
emitting fluorescence or the generated e and h are recombined
2
rapidly. We are currently trying to understand the synergistic
effect between Cu2ꢀxSe & TiO2 components and establish a
thorough mechanism by employing different experimental
conditions (power and position of the lamp, filters used, stirring
speed, formic acid concentration…). These asꢀprepared
photocatalysts can be recycled with only a slight decrease in the
activity (Fig. S12). To test the chemical stability of the catalysts,
we carried out blank photocatalytic experiments using water and
1
5
2
2
3
3
0
5
0
5
photocatalytic activities visꢀàꢀvis pure TiO . For these samples,
2
acidic water (HNO , pH = 3.68, 26 °C) in place of formic acid
3
FA was completely degraded within 45 minutes under UV
under UV radiation. We observed no significant peak of any
organic molecule from HPLC results, thus conforming that these
catalysts remain chemically stable during photocatalytic
experiments (Fig. S13).
radiation. This improved efficiency of the TiO ꢀCu2ꢀxSe
2
nanocomposites can be attributed to an enhanced light absorption
ꢀ
+
property and an increased separation of e ꢀh pairs in these
6
,38
composites (Fig. S10), as also noted previously.
This charge
transfer process is thermodynamically favored as both the
conduction band and the valence band of Cu2ꢀxSe lie above that of
Conclusions
ꢀ
+
TiO2, and the e ꢀh transfer process is faster than its
9
ꢀ
+
t
recombination. The Cu SeꢀTiO nanocomposite generates e ꢀh
Divergent reactivity of Bu
2
Se with copper reagents is presented.
2
ꢀx
2
pairs when irradiated with UVꢀvisible light (eqn S1ꢀ2 in the 70 It includes direct synthesis of copper selenide nanoparticles from
t
Supporting Information). On one hand, electrons produced reacts
the reaction of ditertiarybutyl selenide ( Bu Se) and copper(II)
2
▪
ꢀ
with adsorbed oxygen molecules to form superoxide radicals (O2
trifluoroacetate
[Cu(TFA)2].
Successful
isolation
and
+
)
, the positively charged holes (h ), on the other hand, generate
HCOO radical upon reaction with HCOOH dissolved in H O
characterization of an intermediate molecular species
▪
t
2
[Cu (TFA) ( Bu Se) ] during the course of this reaction
2
2
2
3
(
eqn S3ꢀ4 in the Supporting Information). These are consistent 75 established unequivocally the route for the formation of copper
39
with previous observations. Formic acid then gives CO , while
2
6
| Journal Name, [year], [vol], 00–00
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DOI: 10.1039/C8DT01625A
selenide nanoparticles. The mild conditions required to get these
narrowꢀband gap semiconducting Cu2ꢀxSe NPs offered an easy
synthesis of n%Cu2ꢀxSeꢀTiO2 nanocomposites with different
Cu/Ti ratios, among which n = 0.1 and 0.3 mol% showed
improved photocatalysis in comparison to the commercial
13 L. Zhu, Y. Zhao, W. Zheng, N. Ba, G. Zhang, J. Zhang, X. Li, H.
Xiea and L. Bie, CrystEngComm, 2016, 18, 5202ꢀ5208.
14 S. Q. Lie, D. M. Wang, M. X. Gaoa and C. Z. Huang, Nanoscale,
6
7
7
8
8
9
9
5
0
5
0
5
0
5
2
014, 6, 10289–10296.
1
1
1
5 G. Tian, T. Zhao, J. Niu, H. Shen and L. S. Lia, RSC Adv., 2014, 4,
39547–39551.
6 W. Wang, L. Zhang, G. Chen, J. Jiang, T. Ding, J. Zuoa and Q. Yang,
CrystEngComm, 2015, 17, 1975–1981.
5
available TiO (P25) for the formic acid degradation under UV
2
irradiation. Additional studies are currently underway to optimize
the synthetic and experimental conditions to improve further the
photocatalytic activity of these nanocomposites.
7
(a) S. Mishra and S. Daniele, Chem. Rev., 2015, 115, 8379ꢀ8448; (b)
K. Soussi, S. Mishra, E. Jeanneau, J.ꢀM. M. Millet and S. Daniele,
Dalton Trans., 2017, 46, 13055–13064 ; (c) S. Mishra, E. Jeanneau,
M. Rolland and S. Daniele, RSC Adv., 2016, 6, 1738ꢀ1743; (d) S.
Mishra, E. Jeanneau, S. Mangematin, H. Chermette, M. Poor Kalhor,
G. Bonnefont, G. Fantozzi, S. Le Floch, S. Pailhes and S. Daniele,
Dalton Trans., 2015, 44, 6848ꢀ6862; (e) S. Mishra, V. Mendez, E.
Jeanneau, V. Caps and S. Daniele, Eur. J. Inorg. Chem., 2013, 500ꢀ
510; (f) S. Mishra, E. Jeanneau, M.ꢀH. Berger, J.ꢀF. Hochepied and S.
Daniele, Inorg. Chem., 2010, 49, 11184ꢀ11189; (g) S. Mishra, E.
Jeanneau, S. Daniele and V. Mendez, Dalton Trans., 2010, 39, 7440ꢀ
7443.
1
0
Conflicts of interest
There are no conflicts of interest to declare.
Acknowledgements
SG thanks the French ministry of higher education, research and
innovation for her PhD grant (doctoral school of chemistry,
Lyon). Authors also thank M. Aouine and L. Burel (electron
microscopic measurements), Dr. L. Cardenas (XPS), Y. Aizac
1
5
1
1
8
9
(a) H. Lu and R. L. Brutchey, Chem. Mater., 2017, 29, 1396−1403;
(b) S. Gupta, H. Joshi, N. Jain and A. K. Singh, J. Mol. Catal. A:
Chem., 2016, 423, 135–142; (c) R. K. Sharma, G. Kedarnath, V. K.
Jain, A. Wadawale, C. G. S. Pillai, M. Nalliath and B. Vishwanadh,
Dalton Trans., 2011, 40, 9194–9201; (d) M. Afzaal, M. A. Malik and
P. O’Brien, J. Mater. Chem., 2010, 20, 4031–4040.
(a) Y.ꢀP. Chang, A. L. Hector, W. Levason, G. Reid and J. Whittam,
Dalton Trans., 2018, 47, 2406ꢀ2414: (b) C. Gurnani, S. L. Hawken,
A. L. Hector, R. Huang, M. Jura, W. Levason, J. Perkins, G. Reid and
G. B. G. Stenning, Dalton Trans., 2018, 47, 2628ꢀ2637; (c) Y.ꢀP.
Chang, A. L. Hector, W. Levason and G. Reid, Dalton Trans., 2017,
46, 9824ꢀ9832; (d) K. George, C. H. de Groot, C. Gurnani, A. L.
Hector, R. Huang, M. Jura, W. Levason and G. Reid, Chem. Mater.,
(PXRD) and P. Mascunan (BET measurements) of IRCELYON.
We are grateful to Prof. S. Daniele for his constant
encouragement.
2
0
Notes and references
a
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON-
UMR 5256, 2 avenue Albert Einstein, 69626 Villeurbanne, France
b
Univ Lyon, Université Claude Bernard Lyon 1, Centre de
2
3
3
4
4
5
5
6
5
0
5
0
5
0
5
0
Diffractométrie Henri Longchambon, 5 rue de La Doua, 69100
Villeurbanne, France
S. M.: e-mail, shashank.mishra@ircelyon.univ-lyon1.fr.
Fax: 33-472445399; Tel: 33 472445322.
2
013, 25, 1829ꢀ1836; (e) S. L. Benjamin, C. H. de Groot, C. Gurnani,
A. L. Hector, R. Huang, K. Ignatyev, W. Levason, S. J. Pearce, F.
Thomas and G. Reid, Chem. Mater., 2013, 25, 4719ꢀ4724; (f) C. H.
de Groot, C. Gurnani, A. L. Hector, R. Huang, M. Jura, W. Levason
and G. Reid, Chem. Mater., 2012, 24, 4442ꢀ4449; (g) A. L. Hector,
M. Jura, W. Levason, S. D. Reid and G. Reid, New J. Chem., 2009,
†
Electronic Supplementary Information (ESI) available: Powder XRD,
SEM, STEM, TEM and EDX of Cu2ꢀxSe and Cu2ꢀxSeꢀTiO composites
obtained under different conditions, experimental setup and graphical
plots of photodegradation of formic acid by Cu2ꢀxSeꢀTiO and recycled
1
1
1
1
1
1
1
00
05
10
15
20
2
3
3, 641ꢀ645;
2
2
0
(a) J. R. Sparks, R. He, N. Healy, M. Krishnamurthi, A. C. Peacock,
P. J. Sazio, V. Gopalan and J. V. Badding, Adv. Mater., 2011, 23,
1647ꢀ1651; (b) N. D. Boscher, C. J. Carmalt, R. G. Palgrave and I. P.
Parkin, Thin Solid Films, 2008, 516, 4750ꢀ4757; (c) N. D. Boscher,
C. J. Carmalt, G. Hyett, A. G. Prieto, Q. A. Pankhurst and I. P.
Parkin, J. Mater. Chem., 2008, 18, 1667ꢀ1673; (d) N. D. Boscher, C.
J. Carmalt and I. P. Parkin, J. Mater. Chem., 2006, 16, 122ꢀ127; (e)
N. D. Boscher, C. J. Carmalt, R. G. Palgrave, J. J. GilꢀTomas and I.
P. Parkin, Chem. Vap. Deposition, 2006, 12, 692ꢀ698; (f) N. D.
Boscher, C. J. Carmalt and I. P. Parkin, Eur. J. Inorg. Chem., 2006,
catalysts under UVꢀvisible region. CCDC 1835505ꢀ1835506 contain the
supplementary crystallographic data for this article. These data can be
obtained free of charge from the Cambridge Crystallographic Data
Centre. For ESI and crystallographic data in CIF or other electronic
format see DOI: 10.1039/b000000x/.
1
2
3
4
5
6
7
8
9
1
1
1
R. Daghrira, P. Droguia and D. Robertb, J. Photochem. Photobiol. A
Chem., 2012, 238, 41–52.
M. Kapilashrami, Y. Zhang, Y.ꢀS. Liu, A. Hagfeldt and J. Guo, Chem.
Rev., 2014, 114, 9662ꢀ9707.
1
255ꢀ1259.
Y. Liu, P. Zhang, B. Tian and J. Zhang, Catal. Commun., 2015, 70,
2
1
(a) K. Ramasamy, M. A. Malik, N. Revaprasadu and P. O’Brien,
Chem. Mater. 2013, 25, 3551–3569; (b) M. Afzaal, M. A. Malik and
P. O’Brien, J. Mater. Chem. 2010, 20, 4031–4040.
3
0–33.
J. Lee, T. G. Kim, H. Choi and Y. Sung, Cryst. Growth Des., 2007, 7,
588–2593.
2
2
2
2
3
A. Turki, C. Guillard, F. Dappozze, G. Berhault, Z. Ksibi and H.
Kochkar, J. Photochem. Photobio. Chem. 2014, 279, 8–16.
CrysAlisPro, Agilent Technologies, Version 1.171.34.49 (release 20ꢀ
01ꢀ2011 CrysAlis171 .NET) (compiled Jan 20 2011,15:58:25).
R. C. Clark and J. S. Reid, Acta Cryst. A, 1995, 51, 887ꢀ897.
A. Altomare, M. C. Burla, M. Camalli, G. L. Cascarano, C.
Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. Polidori and R.
Spagna, J. App. Cryst., 1999, 32, 115ꢀ119.
Z. Hana, L. Ren, M. Luo, L. Chen, H. Pan, C. Li, J. Chen and
J. Lan, J. Mol. Catal. A: Chem., 2016, 425, 229–236.
W. L. Ong, Y. Lim, J. L. T. Ong and G. W. Ho, J. Mater. Chem. A.,
2015, 3, 6509–6516.
S. Mishra, D. Du, E. Jeanneau, F. Dappozze, C. Guillard, J. Zhang
and S. Daniele, Chem. Asian J., 2016, 11, 1658–1663.
B. Chong, W. Zhu, Y. Liu, L. Guan and G. Z. Chen, J. Mater. Chem.
A., 2016, 4, 1336–1344.
2
2
4
5
25 26 P. W. Betteridge, J. R. Carruthers, R. I. Cooper, K. Prout and D. J.
C. Coughlan, M. Ibáñez, O. Dobrozhan, A. Singh, A. Cabot and
K.Ryan, Chem. Rev., 2017, 117, 5865–6109.
D. Chen, G. Chen, R. Jinb and H. Xua, CrystEngComm, 2014, 16,
Watkin, J. Appl. Cryst., 2003, 36, 1487.
2
2
7
A. L. Hector, M. Jura, W. Levason, S. D. Reid and G. Reid, New J.
Chem., 2009, 33, 641–645.
0
1
2
810–2817.
8 A. C. Jones and M. L. Hitchman, Chemical Vapour Deposition:
Precursors, Processes and Applications, Royal Society of Chemistry,
D. Li, Z. Zheng, Y. Lei, S. Ge, Y. Zhang, Y. Zhang, K. Wong, F.
Yanga and W. Lau, CrystEngComm. 2010, 12, 1856–1861.
30
2
009.
S. Mishra, E. Jeanneau and S. Daniele, Polyhedron, 2010, 29, 500–
06.
2 X. Liu, X. Duan, P. Penga and W. Zheng, Nanoscale, 2011, 3, 5090–
095.
2
9
5
5
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 7

Dalton Transactions
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DOI: 10.1039/C8DT01625A
3
0
(a) W. Ji, J. Qu, C.ꢀA. Li, J.ꢀW. Wu, S. Jing, F. Gao, Y.ꢀN. Lv, C.
Liu, D.ꢀR. Zhu, X.ꢀM. Ren and W. Huang, Appl. Catal. B: Environ.,
017, 205, 368–375; (b) W. Ji, J. Qu, S. Jing, D. Zhu and W. Huang,
2
Dalton Trans., 2016, 45, 1016ꢀ1024; (c) Y.ꢀQ. Liu, W. Ji, H.ꢀY.
Zhou, Y. Li, S. Jing, D.ꢀR. Zhu and J. Zhang, RSC Adv., 2015, 5,
5
0
5
0
5
0
5
0
4
2689ꢀ42697; (d) A. Panda, Coord. Chem. Rev., 2009, 253, 1056; (e)
W. Levason, S. Orchard and G. Reid, Coord. Chem. Rev., 2002, 225,
59; (f) M. Knorr, A. Bonnot, A. Lapprand, A. Khatyr, C.
1
Strohmann, M. M. Kubicki, Y. Rousselin and P. D. Harvey, Inorg.
Chem., 2015, 54, 4076–4093.
1
1
2
2
3
3
4
3
1
(a) Y. Chen, S. Mishra, G. Ledoux, E. Jeanneau, M. Daniel, J. Zhang
and S. Daniele, Chem. Asian J., 2014, 9, 2415ꢀ2421; (b) S. Mishra, E.
Jeanneau, A.ꢀL. Bulin, G. Ledoux, B. Jouguet, D. Amans, A. Belsky,
S. Daniele and C. Dujardin, Dalton Trans., 2013, 42, 12633ꢀ12643;
c) S. Mishra, L. G. HubertꢀPfalzgraf, S. Daniele, M. Rolland, E.
Jeanneau and B. Jouguet, Inorg. Chem. Commun., 2009, 12, 97ꢀ100.
(a) S. Mishra, E. Jeanneau, G. Ledoux and S. Daniele, Inorg. Chem.,
3
3
2
3
2
014, 53, 11721ꢀ11731; (b) S. Mishra, E. Jeanneau, G. Ledoux and S.
Daniele, CrystEngComm, 2012, 14, 3894–3901; (c) S. Mishra, E.
Jeanneau, S. Daniele and L. G. HubertꢀPfalzgraf, CrystEngComm,
2
008, 10, 814–816.
M. Knorr, A. Pam, A. Khatyr, C. Strohmann, M. M. Kubicki, Y.
Rousselin, S. M. Aly, D. Fortin and P. D. Harvey, Inorg. Chem.
2
010, 49, 5834–5844.
34 S. Mishra, J. Zhang, L. G. HubertꢀPfalzgraf, D. Luneau and E.
Jeanneau, Eur. J. Inorg. Chem., 2007, 602–608.
W. Ji, Ji. Qua, C.ꢀA. Li, J.ꢀW. Wu, S. Jing, F. Gao, Y.ꢀN. Lv, C.
Liu, D.ꢀR. Zhu, X.ꢀM. Ren and W. Huang, Appl. Catal. B: Environ.
3
5
2
017, 205, 368–375.
36 (a) B. Bhattacharyya and A. Pandey, J. Am. Chem. Soc., 2016, 138,
0207ꢀ10213; (b) Y.ꢀJ. Yuan, G. Fang, D. Chen, Y. Huang, L.ꢀX.
Yang, D. Cao, J.ꢀJ. Wang, Z. T. Yu and Z. Zou, Dalton Trans.,
018, 47, 5652ꢀ5659.
1
2
3
7
W. Ou,Y. Zou, K. Wang, W. Gong, R. Pei, L. Chen, Z. Pan, D. Fu,
X. Huang, Y. Zhao, W. Lu and J. Jiang, J. Phys. Chem. Lett., 2018, 9,
2
74−280.
3
3
4
8
9
0
A. Turki, H. Kochkar, C. Guillard, G. Berhault and A. Ghorbel, Appl.
Catal. B,. 2013, 138-139, 401ꢀ415.
A. Hamandi, G. Berhault, C. Guillard and H. Kochkar, Mol. Catal.
2017, 432, 125ꢀ130.
M. F. J. Dijkstra, H. J. Panneman, J. G. M. Winkelman, J. J. Kelly
and A. A. C. M. Beenackers, Chem. Eng. Sci., 2002, 57, 4895ꢀ4907.
8
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DOI: 10.1039/C8DT01625A
Graphical Abstract
Precursor-mediated synthesis of Cu Se
2
-x
nanoparticles and its nanocomposites with
TiO for improved photocatalysis
2
S. Gahlot, E. Jeanneau, F. Dappozze, C. Guillard
and S. Mishra*
Simple, but effective. Successful isolation and
characterization of an intermediate during the
t
reaction of Bu Se with Cu(TFA) establishes the
2
2
route for the formation of copper selenide NPs and
Cu SeꢀTiO composites as active photocatalysts.
2ꢀx
2
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 9