Magnetically Recyclable Fe3O4@ZnxCd1-xS Core-Shell Microspheres for Visible Light-Mediated Photocatalysis

Article abstract of DOI:10.1021/acs.langmuir.8b01413

Magnetically recyclable photocatalyst has drawn considerable research interest because of its importance in practical applications. Herein, we demonstrate a facile hydrothermal process to fabricate magnetic core-shell microspheres of Fe₃O₄@Zn_xCd_1-xS, successfully using Fe₃O₄@ZnS core-shell microspheres as sacrificed templates. The as-prepared magnetically recyclable photocatalysts show efficient photochemical reduction of Cr(VI) under irradiation of visible light. The photochemical reduction mechanism has been studied to illustrate the reduction-oxidation ability of the photogenerated electrons (e^-) and holes (h⁺), which play an important role in the reduction of Cr(VI) to Cr(III) and oxidation of organic dyes. The as-prepared Fe₃O₄@Zn_0.55Cd_0.45S core-shell microspheres show good chemical stability and only a slight decrease in the photocatalytic activity after four recycles. In particular, the as-prepared photocatalysts could be easily recycled and reused by an external magnetic field. Therefore, this work would provide a facile chemical approach for controlled synthesis of magnetic nanostructures combined with alloyed semiconductor photocatalysts for wastewater treatment.

Full text of DOI:10.1021/acs.langmuir.8b01413

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Interface-Rich Materials and Assemblies
Magnetically Recyclable Fe3O4@ZnxCd1-xS Core-shell
Microspheres for Visible Light Mediated Photocatalysis
Jun Zhang, Wanni Wang, Mengli Zhao, Chenyang Zhang,
Chenxi Huang, Sheng Cheng, Hongmei Xu, and Haisheng Qian
Langmuir, Just Accepted Manuscript • DOI: 10.1021/acs.langmuir.8b01413 • Publication Date (Web): 13 Jul 2018
Downloaded from http://pubs.acs.org on July 15, 2018
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Magnetically Recyclable Fe O @Zn Cd S Core-
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x
1-x
shell Microspheres for Visible Light Mediated
Photocatalysis
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a
a
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b
Jun Zhang , Wan-Ni Wang , Meng-Li Zhao , Chen-Yang Zhang , Chen-Xi Huang , Sheng Cheng ,
a,
a,c,
Hong-Mei Xu * and Hai-Sheng Qian *
a
Department of Medical Materials and Rehabilitation Engineering, School of Biological and Medical
Engineering, Hefei University of Technology, Hefei 230009, P. R. China.
b
Instrumental Analysis Center, Hefei University of Technology, Hefei 230009, P. R. China.
c
Biomedical and Environmental Interdisciplinary Research Centre, Hefei, 230010, P. R. China.
.
Correspondence should be addressed to:
Prof. H. M. Xu, Eꢀmail: xuhongmei@hfut.edu.cn.
Prof. H. S. Qian, Eꢀmail: shqian@hfut.edu.cn. Fax: +86 551 62901285
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Abstract: Magnetically recyclable photocatalyst has drawn considerable research interest due to its
importance for practical applications. Herein we demonstrate a facile hydrothermal process to fabricate
magnetic coreꢀshell microspheres of Fe O @Zn Cd S successfully using Fe O @ZnS coreꢀshell
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microspheres as sacrificed templates. The asꢀprepared magnetically recyclable photocatalysts show
efficient photochemical reduction of Cr(VI) under irradiation of visible light. The photochemical
reduction mechanism has been studied to illustrate the reductionꢀoxidation ability of the photoꢀgenerated
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electrons (e ) and holes (h ); which play an important role in reduction of Cr(VI) to Cr(III) and oxidation
of organic dyes. The asꢀprepared Fe O @Zn0.55Cd0.45S coreꢀshell microspheres show good chemical
3
4
stability and only a slight decreasing in photocatalytic activity after four recycles. In particular, the asꢀ
prepared photocatalysts could be easily recycled and reused by an external magnetic field. Therefore,
this work would provide a facile chemical approach for controlled synthesis of magnetic nanostructures
combining alloyed semiconductor photocatalysts for wastewater treatment.
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. Introduction
Semiconductor photocatalysis is widely recognized as one of the most promising techniques, which
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can harness the solar energy directly for practical applications in solar fuels,
waste water/air
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treatment
and chemical synthesis.
However, catalystꢀrecovery for semiconductor photocatalysts
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is a big obstacle for their practical application.
Magnetic separation, known as the magnetic iron
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oxide–photocatalysts system, is widely concerned as an effective solution and it has drawn considerable
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research interest.
Till now, much effort has been made to fabricate magnetic recyclable composite
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photocatalysts, for instance, magnetic iron oxideꢀnoble metal system, including Fe O ꢀAu,
Fe O ꢀ
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Ag,
Fe O ꢀPt,
magnetic iron oxideꢀgraphene/graphene oxide system,
magnetic iron oxideꢀ
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2ꢀ45
MOFs system,
and the magnetic iron oxide–semiconductor photocatalysis system, including Fe O ꢀ
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6ꢀ49
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TiO2,
Fe O ꢀWO , Fe O ꢀCdS,
Fe O ꢀMoS , Fe O ꢀgꢀC N
and so on. Recently, Huang
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and coꢀworkers have successfully synthesized a unique CdS/C@Fe O nanoreactor by the surfaceꢀ
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imprinting technique. Zuo et al have reported magnetic γꢀFe O @ZnO coreꢀshell photocatalyst, which
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was firstly fabricated by hydrothermal and atomic layer deposition (ALD) method. More recently,
templating approach has been developed to synthesize various Fe O @void@TiO yolkꢀshell
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59
microspheres.
However, it’s still a challenging work to compound incorporated magnetic nanoparticles and binary
sulfide photocatalysts directly owing to large lattice mismatch between them. Additionally, single
counterpart of ZnS and CdS has a weak resistance towards photoꢀcorrosion, resulting into limiting their
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applications.
Compared to binary sulfide, alloyed Zn Cd S, especially for the alloys of Zn Cd S
x 1ꢀx 0.5 0.5
(mole ratio of Zn/Cd approximate 1.0) has been employed to be a superior substitute to avoid these
ꢀ
+ 63ꢀ65
drawbacks by enhancing the separated efficiency of photoꢀgenerated electrons (e ) and holes (h ).
To
the best of our knowledge, the iron oxideꢀternary semiconductor sulfide composite photocatalysis
system is rarely reported.
Herein, a facile template strategy involved multiꢀsteps has been proposed to synthesize
Fe O @Zn Cd S coreꢀshell microspheres (mole ratio of Zn/Cd approximate 1.0) using Fe O @ZnS
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1ꢀx
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coreꢀshell microspheres as hard template, Cd(Ac) and thiourea used as reagents. Before that,
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Fe O @AAꢀ[Zn(OH) ] coreꢀshell microspheres are prepared, which can be converted to Fe O @ZnS
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microspheres via a gaseous sulfidation process. The accurate chemical composition of the mole ratio
of Cd/Zn and band structure has been investigated using UVꢀVis diffuse reflectance spectroscopy (DRS)
and atomic absorption spectroscopy (AAS), respectively. The photochemical reduction of Cr(VI) and
oxidation of organic dyes have been demonstrated under irradiation of visible light.
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. Experimental section
All chemicals were of analytic grade and used as received. The Fe O microspheres with average
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size of ca. 300 nm were synthesized by a typical solvothermal reaction.
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Fabrication of Fe O @AA-[Zn(OH) ] composite microspheres
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Fe O @AAꢀ[Zn(OH) ] microspheres with a tunable shell thickness have been prepared via a
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modified procedure according to the reported protocol.
Typically, for the synthesis of Fe O @AAꢀ
3 4
2
ꢀ
[Zn(OH)4] microspheres with 40 nm in shell thickness, 0.12mmol LꢀAscorbic acid (AA) and
.36mmol hexadecyltrimethylammonium bromide (CTAB) were dissolved using 40 mL deionized water
in a flask. And then, 10mg Fe O microspheres was added and kept stirring for 15 min. After that, 0.045
0
3
4
mmol of Zn(NO ) ·6H O and 0.045 mmol of hexadecyltrimethylammonium (HMTA) were added into
3 2
2
o
the flask. Subsequently, the mixture solution was heated to 85 C for 10h. Finally, the product was
2ꢀ
washed with deionized water and ethanol for several times. For comparison, Fe O @AAꢀ[Zn(OH) ]
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microspheres with shell thickness of 60 nm and 20 nm have been prepared by adding double or quarter
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ꢀ
of AA, Zn(NO ) ꢁ6H O and HMTA. The asꢀprepared Fe O @AAꢀ[Zn(OH) ] microspheres can be
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converted to Fe O @ZnS microspheres via a simple gaseous sulfidation process.
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Synthesis of Fe O @Zn Cd S core-shell microspheres
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1-x
Typically, 0.25 mmol cadmium acetate and 3.82 mmol thiourea and 10mg Fe O @ZnS
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microspheres with 40nm in shell thickness was added into 24 mL deionized water and stirred for 30 min.
The mixture solution was transferred into a Teflonꢀlined stainlessꢀsteel autoclave (total volume is 30
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mL), which was maintained at 140 C for 1.5h. The final product was washed with deionized water and
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ethanol for several times and dried at 60 C for 12h. And along with the changes of the shell thickness,
the dosage was adjused to 0.11mmol cadmium acetate and 1.76 mmol thiourea for 20 nm in shell
thickness and 0.37mmol cadmium acetate and 6.0 mmol thiourea for 60 nm while the other condition
was kept at the same.
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Photocatalytic experiments
The photocatalytic activities of asꢀprepared Fe O @Zn Cd S coreꢀshell microspheres were
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x
1ꢀx
evaluated by photocatalytic reduction of Cr(VI) and degradation of methylene blue (MB). Briefly, 10 mg
ꢀ1
asꢀprepared magnetic composite microspheres and 50 mL of Cr(VI) aqueous solution (5 mgꢁL ) were
added into a 100 mL glass beaker and the mixed solution was shaked in dark for 1h to reach the
adsorption/desorption equilibrium. Subsequently, the mixed solution was exposed to a Xe lamp (1500
2
mWꢁcm ) with wavelength of 320–1100 nm for 35 min. 3 mL of the solution was taken out every 5 min
and the catalysts were separated off by magnet. The concentration of Cr(VI) was measured by the
diphenylcarbazide (DPC) method. The degradation experiments of MB were taken by the same
procedure and characterized the concentration with the characteristic absorption peak at 663 nm of MB.
3
. Results and Discussion
The synthetic protocol of Fe O @Zn Cd S coreꢀshell microspheres involves three steps, which is
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4
x
1ꢀx
2ꢀ
illustrated in Figure 1a. Figure 1b shows the TEM image of Fe O @AAꢀ[Zn(OH) ] coreꢀshell
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composite microspheres with 40 nm in shell thickness and the core component is with ca. 400 nm in
diameter consistent with the size of Fe O microspheres shown in Figure S1a(in the supporting
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information).
Figure S1b (in the supporting information) shows the TEM image of the Fe O @ZnS
3 4
2ꢀ
complex composite microspheres after gas sulfidation of Fe O @AAꢀ[Zn(OH) ] composite
3
4
4
microspheres. Figure 1c shows the TEM image of the sample obtained from Cd(Ac) , thiourea and
2
o
Fe O @ZnS microspheres at 140 C for 4h; in which the product was comprised of microspheres with
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coreꢀshell nanostructures. In addition, the shell component is consisted of small crystalline
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nanoparticles, as revealed from the HRTEM image shown in Figure 1d. The lattice fringe of 3.16 Å
taken from the small nanoparticle can be indexed to (101) crystal plane of Zn Cd S with hexagonal
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phase. Figure 1e-i, STEM image and the elemental distribution mapping images of the composite
microspheres demonstrate that Fe distributes in the inner component and elements of S, Zn and Cd was
incorporated into the shell layer homogeneously. The merge image incorporated Zn and Fe confirmed
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that the Fe O @Zn Cd S coreꢀshell nanostructures have been synthesized successfully.
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Figure 1. (a) Schematic illustration of the synthetic strategy of Fe O @Zn Cd S coreꢀshell
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x
1ꢀx
2
ꢀ
microspheres; (b) TEM image of Fe O @AAꢀ[Zn(OH) ] coreꢀshell microspheres; (c,d) TEM and
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HRTEM images of Zn0.51Cd0.49S coreꢀshell microspheres; (e) STEM image of the Fe O @Zn0.51Cd0.59
S
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coreꢀshell microspheres; (fꢀi) STEM elemental mapping images of S, Zn, Cd, Fe and merged image of
the elements of Zn and Fe.
The phase and chemical composition of the Fe O @Zn Cd S composites have been investigated
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x
1ꢀx
using XRD, AAS and XPS, respectively. The sharp diffraction peaks in XRD pattern shown in Figure
7
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2a can be assigned to spinel ferrite (Fe O , JCPDS No. 75ꢀ1609). The three wide and weak diffraction
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peaks are derived from the shell component. As shown in Figure S2( in the supporting information),
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the three Gaussian peaks located at 25.90, 26.92 and 28.22 are very fitted to the wide diffraction peaks
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located at 27.5 , slightly higher than that of the pure CdS, demonstrating alloyed Zn Cd S
x
1ꢀx
nanostructures formed in this work. The chemical composition calculated from EDX spectra has been
shown in Table S1 (in the supporting information). The atomic ratio of Zn/Cd in Fe O @Zn Cd S is
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x
1ꢀx
0
.51/0.49 using atomic absorption spectroscopy (AAS) (Table S2, in the supporting information).
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Thus, the Fe O @Zn0.51Cd0.49S coreꢀshell microspheres have been synthesized successfully via the
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present synthetic protocol. Moreover, the shell thickness of the asꢀprepared Fe O @Zn0.51Cd0.49S coreꢀ
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2ꢀ
shell microspheres can be tunable by using the Fe O @AAꢀ[Zn(OH) ] complex composite
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microspheres with different shell thickness (Figure S3, in the supporting information).
(
a)
(b) 80
CdS JCPDS 41-1049
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0
Fe O
3 4
20
0
Fe O @Zn0.51Cd0.49S
3 4
-
20
-40
Fe O4 JCPDS 75-1609
3
-
-
60
80
10
20
30
40
50
60
70
-
15000-10000 -5000
0
5000 10000 15000
2θ (degree)
H(Oe)
Figure 2. (a) XRD patterns of the Fe O @Zn0.51Cd0.49S coreꢀshell microspheres; (b) magnetic
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hysteresis loops of Fe O and Fe O @Zn0.51Cd0.49S microspheres at 300K, inset pictures showing
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Fe O and Fe O @Zn0.51Cd0.49S coreꢀshell microspheres can be recycled from aqueous solution by an
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external magnetic field.
Figure 2b is the magnetic hysteresis loops of Fe O and Fe O @Zn0.51Cd0.49S microspheres, the
3
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Fe O @Zn0.51Cd0.49S coreꢀshell microspheres exhibit paramagnetic performance and the saturation
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magnetization reaches up to 30.15 emu/g at 300K, which is accordance with that of spinel ferrite
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previously reported. Figure 3a shows a general survey of the Xꢀray photoelectron spectroscopy
(XPS) of the Fe O @Zn0.51Cd0.49S microspheres, verifying the coꢀexistence of the elements including
3
4
Fe, Zn, Cd, S and O elements. As shown in Figure 3b,c, the binding energies centered at 1044.98,
2+
1
021.98, 411.78, and 405.08 eV can be assigned to the binding energies of Zn 2p of Zn and Cd 3d of
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2
+
Cd , respectively. The weak peaks centered at 732.08, 724.39, and 710.50 eV can be fitted to four
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Gaussian peaks located at 732.08, 724.39, 711.39 and 710.23 eV (Figure 3d), which can be assigned to
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+
3+
the binding energy of Fe and Fe , confirming that the Spinel phase of Fe O have been prepared and
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used in the present study.
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(
a)
(b)
Zn 2p
Survey
Zn 2p
Fe 2p3/2 O 1s
Fe 2p1/2
Cd 3d
C 1s S 2p
1
000
800
600
400
200
1050
1040
1030
1020
Binding energy (eV)
Binding energy (eV)
(d)
(c)
Fe 2p
Cd 3d
420
415
410
405
400
735
730
725
720
715
710
Binding energy (eV)
Binding energy (eV)
Figure 3. XPS of Fe O @Zn0.51Cd0.49S coreꢀshell microspheres: (a) a general survey; (b) Zn 2p; (c) Cd
3
4
3
d; (d) Fe 2p; respectively.
Figure 4a shows the UVꢀVis diffuse reflectance spectra (DRS) of the Fe O @Zn0.51Cd0.49S coreꢀ
3
4
shell microspheres, in which a wide absorption peak located at 470 nm has been clearly observed,
6
9
which is a obviously blueꢀshift compared to pure CdS, indicating the formation of alloyed Zn Cd S.
x
1ꢀx
The bandꢀgap energy of the Fe O @Zn0.51Cd0.49S coreꢀshell microspheres has been evaluated from the
3
4
2
72
DRS according to the KubelkaꢀMunk function [F(R)hν] versus photon energy (hν) (Figure 4b).
Thus, Fe O @Zn Cd S coreꢀshell microspheres has been prepared successfully via the present
3
4
x
1ꢀx
protocol. As expected, the asꢀprepared Fe O @Zn Cd S composite microspheres with magnetic
3
4
x
1ꢀx
recyclability can be widely applied in wastewater treatment in the near future.
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.0
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00
400
600
800
1000
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Wavelength (nm)
hυ (eV)
Figure 4. (a) UV–Vis diffuse reflectance spectra (DRS) of the Fe O @Zn0.51Cd0.49S microspheres; (b)
KubelkaꢀMunk plots used to estimate the band gap energy for the Fe O @Zn0.51Cd0.49S microspheres.
3
4
3
4
(
Eg=1.83 eV).
Alloyed Zn Cd S nanostructures has been widely used in photocatalytic reduction or oxidation
x
1ꢀx
6
3ꢀ65
towards inorganic ions or organic dyes.
Herein Cr(VI) and methylene blue (MB) have been selected
as model for investigation of the photocatalytic performance. Diphenylcarbazide (DPC) method has
been widely used to analyze the concentration of Cr(VI) and evaluate the photocatalytic reduction
7
3ꢀ74
ability for the asꢀprepared photocatalyst.
Figure 5a-d show the UVꢀVis absorbance spectra of
Cr(VI)ꢀcomplex and digital photos of the Cr(VI) aqueous solution, demonstrating that the reduction of
Cr(VI) has been efficiently realized in presence of Fe O @Zn0.55Cd0.45S coreꢀshell microspheres under
3
4
irradiation of 1500 mW Xe lamp. In addition, the composite microspheres can be reused and recycled
ꢀ
by a magnet. As shown in Figure 5e, f, more than 90 % of Cr(VI) in 50 mL aqueous solution (5 mg·L
1
)
can be reduced to Cr(III) using 10 mg Fe O @Zn0.55Cd0.45S microspheres after irradiation for 35
3 4
2
ꢀ
min. As expected, the Fe O @Zn0.55Cd S microspheres obtained from Fe O @AAꢀ[Zn(OH) ] coreꢀ
3
4
0.45
3
4
4
shell microspheres with 60 nm in shell thickness show the best photochemical reduction ability
towards Cr(VI) than that of Fe O @Zn0.51Cd0.49S and Fe O @Zn0.55Cd0.45S coreꢀshell microspheres
3
4
3
4
with thinner shell thickness. Particularly, the Fe O @Zn Cd S composite microsphere show excellent
3
4
x
1ꢀx
chemical stability. As shown in Figure 5g, only a slight loss in photocatalytic ability for the asꢀ
prepared Fe O @Zn0.51Cd0.49S coreꢀshell microspheres and more than 85% of Cr(VI) was still photoꢀ
3
4
chemically reduced after four successive recycling photocatalytic experiments. Furthermore, the asꢀ
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prepared Fe O @Zn Cd S composite microspheres also show excellent photoꢀdegradation towards
3
4
x
1ꢀx
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
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4
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4
4
4
4
4
4
4
5
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5
5
5
5
5
5
5
5
6
organic dyes in aqueous solution. As shown in Figure S4 (in the supporting information), 92% of
methylene blue (50 mL, 3.0 mg/L) in aqueous solution can be photoꢀoxidized in 35 min using 5 mg
Fe O @Zn0.55Cd0.45S coreꢀshell microspheres under irradiation of the lamp after four successive
3
4
recycling photocatalytic experiments. The asꢀprepared Fe O @Zn0.55Cd0.45S coreꢀshell microspheres
3
4
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
with thicker shell thickness exhibit excellent photoꢀreduction and photoꢀoxidation ability, which may
be attributed to the increasement of the photocatalyst (Zn0.55Cd0.45S) with thicker shell component. The
photocurrent responses and impedance spectroscopy (EIS) of the asꢀprepared samples have been
operated and shown in Figure 6, which demonstrate and confirm that the Fe O @Zn0.55Cd0.45S coreꢀ
3
4
ꢀ
shell microspheres possess producing more photoꢀgenerated electrons (e ) and higher separation and
migration of photoꢀinduced charge carriers. In addition, the fluorescence spectra of 2ꢀhydroxyl
terephthalic acid shown in Figure S5 (in the supporting information) also show that a considerable
amount of hydroxyl radical (·OH) produced excited using a Xe lamp and the asꢀprepared
7
5
Fe O @Zn0.55Cd0.45S coreꢀshell microspheres shows stronger production ability of hydroxyl radicals.
3
4
All of these indicate that a considerable amount of photoꢀgenerated electrons and holes produced when
the coreꢀshell microspheres under irradiation. As discussed previously, the photoꢀgenerated electrons
+
can reduce the Cr(VI) to Cr(III) and the h can oxidize H O/O to reactive oxygen species (ROS) which
2
2
have strong oxidative ability and take crucial role in the photodegradation reactions and asꢀgenerated
76ꢀ79
ROS can oxidize the organic dyes to carbon oxides and water.
illustrated and summarized as follows:
The reaction formulas can be
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1
1
1
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2
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1
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9
0
(e)
(
d)
-60min
1.0
.8
0
5
1
min
min
0min
0
.3
blank
0
Fe O @Zn0.46Cd0.54S
15min
0min
25min
3
4
2
Fe O @Zn0.51Cd0.49
S
3
4
0.2
Fe O @Zn0.55Cd0.45
3 4
S
3
3
0min
5min
0.6
.4
0
0
.1
.0
0.2
0.0
0
400
500
600
700
-60
0
5
10
15
20
25
30
35
wavelength(nm)
Time (min)
(
g) 1.0
(
f) 2
.5
blank
Fe O @Zn0.46Cd0.54
S
3
4
0
0
.8
.6
Fe O @Zn0.51Cd0.49S
2.0
3
4
Fe O @Zn0.55Cd0.45
S
3
4
1
1
.5
.0
0.4
0.5
.0
0
.2
0
0.0
0
5
101520253035
0
5
101520253035
0
5
101520253035
0
5
10 1520 2530 35
0
5
1015 2025 3035
0
5
10
15
20
25
30
35
Time (min)
Time (min)
Figure 5. (aꢀc) Digital photos of Cr(VI) aqueous solution with Fe O @Zn0.55Cd0.45S after irradiation of
3
4
NIR light for 0, 10 and 35 min; (d) UVꢀVis absorbance spectra of Cr(VI)ꢀcomplex in presence of
Fe O @Zn0.55Cd0.45S microspheres under irradiation of 1500 mW Xe lamp for different time; (e, f)
3
4
photochemical reduction and kinetic curves of Cr(VI) in presence of different Fe O @Zn Cd S under
3
4
x
1ꢀx
irradiation, C : the concentration of initial solution, C : the concentration at the irradiation time; (g) five
0
t
recycling tests of photoreduction of Cr(VI) under irradiation for 35 min using 10 mg
Fe O @Zn0.55Cd0.45S.
3
4
ꢀ
In fact, the photoꢀgenerated e as the sole reductive species, it can also react with Fe(III) in the interface
2
ꢀ
of Fe O @Zn Cd S coreꢀshell and also reduce O to obtain·O . To clarify the competitive relationship
3
4
x
1ꢀx
2
between the two reactions and some comparative experiments have been carried out to evaluate the
ꢀ
influence of the reduction of Cr(VI) and the reduction between Fe(III) and e . As shown in Fig. S6, 7(in
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the supporting information), the photochemical reduction and kinetic curves of Cr(VI) in presence of 10
mg Fe O , 10 mg Zn0.43Cd0.57S as well as their mixture under irradiation show that Zn0.55Cd0.45
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
S
3
4
microspheres exhibit excellent photocatalytic performance towards reduction of Cr(VI) and the catalytic
efficiency of the photocatalysts has a slightly weaken in presence of Fe O , which can be attributed to
3
4
ꢀ
possible reduction of Fe(III) by the photoꢀgenerated e
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
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7
8
9
0
1
2
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7
8
9
0
1
2
3
4
5
6
7
8
9
0
(
a) 0.30
(b) 90000
Fe O @Zn0.55Cd0.45
S
S
S
Fe
Fe
Fe
3
O
4
@Zn0.46Cd0.54
@Zn0.51Cd0.49
O @Zn0.55Cd0.45
3 4
S
S
S
3
4
Fe O @Zn0.51Cd0.49
O
3 4
0
0
.25
.20
3
4
75000
60000
45000
Fe O @Zn0.46Cd0.54
3
4
0.15
.10
0.05
.00
0
3
1
0000
5000
0
0
0
2000
4000
6000
8000
0
50
100
150
200
250
300
Time (s)
Z' (ohm)
Figure 6. (a) Photocurrent responses and (b) impedance spectroscopy (EIS) of the asꢀprepared samples
in dark.
4
. Conclusions
In summary, magnetic recyclable Fe O @Zn Cd S coreꢀshell microspheres have been prepared via
3
4
x
1ꢀx
the facile sacrificedꢀtemplate technique under hydrothermal condition. The magnetic coreꢀshell
microspheres with tunable shell thickness have been obtained by adding different amount of Cd(Ac)2
and thiourea in presence of Fe O @ZnS microspheres with different shell thickness. The asꢀprepared
3
4
Fe O @Zn Cd S coreꢀshell microspheres show good photochemical reduction ability towards Cr(VI)
3
4
x
1ꢀx
and oxidation photoꢀdegradation ability towards of methylene blue dyes under irradiation of visible
light. In addition, successive recycling experiments demonstrate that the asꢀprepared composite
microspheres exhibit excellent chemical stability and recyclability, which is of great importance for
practical applications.
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Supporting Information
The Supporting Information is available free of charge on the ACS Publications website at DOI:
.
Experimental procedure for hydroxyl radical (·OH) detection, fabrication of Zn0.43Cd0.57S hollow
microspheres and characterizations, TEM images (Figure S1, S3, S6), highꢀresolution XRD patterns
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
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1
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1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(Figure S2), photoꢀoxidation of MB (Figure S4), fluorescence spectra (Figure S5), photochemical
oxidation and removal kinetic curves (Figure S5), element composition and accurate mole ratio of
Zn/Cd (Table S1, S2).
Acknowledgement. We acknowledge the funding supports from the National Natural Science
Foundation of China (21471043) and Natural Science Foundation of Anhui Province
(JZ2017AKZR0138). J. Zhang and W. Wang contributed to this work equally.
References
(
1) Zhang, G. G.; Lan, Z. A.; Wang, X. C. Conjugated Polymers: Catalysts for Photocatalytic Hydrogen
Evolution. Angew. Chem. Int. Ed. 2016, 55, 15712ꢀ15727.
(
2) Shi, R.; Cao, Y. H.; Bao, Y. J.; Zhao, Y. F.; Waterhouse, G. I. N.; Fang, Z. Y, Wu, L. Z.; Tung, C. H.;
Yin, Y. D.; Zhang, T. R. SelfꢀAssembled Au/CdSe Nanocrystal Clusters for PlasmonꢀMediated
Photocatalytic Hydrogen Evolution. Adv. Mater. 2017, 29, 1700803.
(3) Chen, G. B.; Gao, R.; Zhao, Y. F.; Li, Z. H.; Waterhouse, G. I. N.; Shi, R.; Zhao, J. Q.; Zhang, M. T.;
Shang L.; Sheng G. Y.; Zhang X. P.; Wen X. D.; Wu L. Z.; Tung C. H.; Zhang T. R. Aluminaꢀ
Supported CoFe Alloy Catalysts Derived from LayeredꢀDoubleꢀHydroxide Nanosheets for Effcient
Photothermal CO Hydrogenation to Hydrocarbons. Adv. Mater. 2018, 30, 1704663.
2
(
4) Yu, H. J.; Shi, R.; Zhao, Y. X.; Bian, T.; Zhao, Y. F.; Zhou, C.; Waterhouse, G. I. N.; Wu, L. Z.;
Tung, C. H.; Zhang, T. R. AlkaliꢀAssisted Synthesis of Nitrogen Defcient Graphitic Carbon Nitride
with Tunable Band Structures for Effcient VisibleꢀLightꢀDriven Hydrogen Evolution. Adv. Mater.
2017, 29, 1605148.
13
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Page 14 of 21
(
(
(
5) Ran, J.; Gao, G.; Li, F. T.; Ma, T. Y.; Du, A.; Qiao, S. Z. Ti C MXene Coꢀcatalyst on Metal Sulfide
3 2
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
PhotoꢀAbsorbers for Enhanced Visibleꢀlight Photocatalytic Hydrogen Production. Nat. Commun.
017, 8, 13907.
2
6) Huang, Z. F.; Song, J. J.; Li, K.; Tahir, M.; Wang, Y. T.; Pan, L.; Wang, L.; Zhang, X. W.; Zou, J. J.
Hollow CobaltꢀBased Bimetallic Sulfide Polyhedra for Efficient AllꢀpHꢀValue Electrochemical and
Photocatalytic Hydrogen Evolution. J. Am. Chem. Soc. 2016, 138, 1359ꢀ1365.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
7) Kudo, A.; Miseki, Y. Heterogeneous Photocatalyst Materials for Water Splitting. Chem. Soc. Rev.
2
009, 38, 253ꢀ278.
(8) Chen, X. B.; Shen, S. H.; Guo, L. J.; Mao, S. S. SemiconductorꢀBased Photocatalytic Hydrogen
Generation. Chem. Rev. 2010, 110, 6503ꢀ6570.
(9) He, B.; Liu, R.; Ren, J. B.; Tang, C. J.; Zhong, Y. J.; Hu, Y. OneꢀStep Solvothermal Synthesis of
+
Petalous CarbonꢀCoated Cu ꢀDoped CdS Nanocomposites with Enhanced Photocatalytic Hydrogen
Production. Langmuir 2017, 33, 6719ꢀ6726.
(
10) Li, X.; Yu, J.; Jaroniec, M. Hierarchical Photocatalysts. Chem. Soc. Rev. 2016, 45, 2603ꢀ2636.
11) Yu, C.; Li, G.; Kumar, S.; Yang, K.; Jin, R. Phase Transformation Synthesis of Novel
Ag O/Ag CO Heterostructures with High Visible Light Efficiency in Photocatalytic Degradation of
(
2
2
3
Pollutants. Adv. Mater. 2014, 26, 892ꢀ898.
(
12) Huang, H. W.; Han, X.; Li, X.W.; Wang, S. C.; Chu, P. K.; Zhang, Y. H. Fabrication of Multiple
Heterojunctions with Tunable VisibleꢀLightꢀActive Photocatalytic Reactivity in BiOBrꢀBiOI Fullꢀ
Range Composites Based on Microstructure Modulation and Band Structures. ACS Appl. Mater.
Interf. 2015, 7, 482ꢀ492.
(
13) Boyjoo, Y.; Sun, H.; Liu, J.; Pareek, V. K.; Wang, S. B. A Review on Photocatalysis for Air
Treatment: From Catalyst Development to Reactor Design. Chem. Eng. J. 2017, 310, 537ꢀ559.
14) Huang, H. W.; Xiao, K.; Zhang, T. R.; Dong, F.; Zhang, Y. H. Rational Design on 3D Hierarchical
Bismuth Oxyiodides via in situ SelfꢀTemplate Phase Transformation and PhaseꢀJunction
Construction for Optimizing Photocatalysis against Diverse Contaminants. Appl. Catal. B-Environ.
2017, 203, 879ꢀ888.
(
(15) Habisreutinger, S. N.; SchmidtꢀMende, L.; Stolarczyk J. K. Photocatalytic Reduction of CO on
2
TiO and Other Semiconductors. Angew. Chem. Int. Ed. 2013, 52, 7372ꢀ7408.
2
(16) Huang, H. W.; He, Y.; Du, X.; Chu, P. K.; Zhang, Y. H. A General and Facile Approach to
Heterostructured Core/Shell BiVO /BiOI pꢀn Junction: RoomꢀTemperature in Situ Assembly and
4
Highly Boosted VisibleꢀLight Photocatalysis. ACS Sustain Chem. Eng. 2015, 3, 3262ꢀ3273.
(17) Wan, Z.; Zhang, G. K.; Wu, X. Y.; Yin, S. Novel VisibleꢀLightꢀDriven ZꢀScheme Bi GeO /gꢀ
1
2
20
C N Photocatalyst: OxygenꢀInduced Pathway of Organic Pollutants Degradation and Proton
3
4
14
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Page 15 of 21
Langmuir
Assisted Electron Transfer Mechanism of Cr(VI) Reduction. Appl. Catal. B-Environ. 2017, 207, 17ꢀ
1
2
3
26.
(
18) Huang, H.W.; Xiao, K.; He, Y.; Zhang, T. R.; Dong, F.; Du, X.; Zhang, Y. H. In situ Assembly of
BiOI@Bi O Cl pꢀn Junction: Charge Induced Unique FrontꢀLateral Surfaces Coupling
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
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5
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5
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5
5
5
5
5
5
6
1
2
17
2
Heterostructure with High Exposure of BiOI {001} Active Facets for Robust and Nonselective
Photocatalysis. Appl. Catal. B: Environ. 2016, 199, 75ꢀ86.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
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2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(
19) Meng, X. D.; Zhang, G. K.; Li, N. Bi Ga O for Visible Light Photocatalytic Reduction of Cr(VI):
2
4
2
39
Controlled Synthesis, FacetꢀDependent Activity and DFT Study. Chem. Eng. J. 2017, 314, 249ꢀ256.
(20) Ong, W. J.; Tan, L. L.; Ng, Y. H.; Yong, S. T.; Chai, S. P. Graphitic Carbon Nitride (gꢀC N )ꢀ
3
4
Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step
Closer To Achieving Sustainability? Chem. Rev. 2016, 116, 7159ꢀ7329.
(21) Schultz, D. M.; Yoon, T. P. Solar Synthesis: Prospects in Visible Light Photocatalysis. Science
2
014, 343, 1239176.
(
22) Zhao, Y. F.; Zhao, Y. X.; Waterhouse, G. I. N.; Zheng, L. R.; Cao, X. Z.; Teng, F.; Wu, L. Z.; Tung,
C. H.; O’Hare, D.; Zhang, T. R. LayeredꢀDoubleꢀHydroxide Nanosheets as Effcient VisibleꢀLightꢀ
Driven Photocatalysts for Dinitrogen Fixation. Adv. Mater. 2017, 29, 1703828.
23) Low, J.; Yu, J.; Jaroniec, M.; Wageh, S.; AlꢀGhamdi, A. A. Heterojunction Photocatalysts. Adv.
Mater. 2017, 29, 1601694.
(
(24) Zhao, Y. F.; Zhao, B.; Liu, J. J.; Chen, G. B., Gao, R.; Yao, S. Y.; Li, M. Z.; Zhang, Q. H.; Gu, L.;
Xie, J. L.; Wen, X. D.; Wu, L. Z.; Tung, C. H.; Ma, D.; Zhang, T. R. OxideꢀModified Nickel
Photocatalysts for the Production of Hydrocarbons in Visible Light. Angew. Chem. Int. Ed. 2016, 55,
4
215ꢀ4219.
(25) GómezꢀPastora, J.; Dominguez, S.; Bringas, E.; Rivero, M. J.; Ortiz, I.; Dionysiou, D. D. Review
and Perspectives on the Use of Magnetic Nanophotocatalysts (MNPCs) in Water Treatment. Chem.
Eng. J. 2017, 310, 407ꢀ427.
(26) Rossi, L. M.; Costa, N. J. S.; Silva, F. P.; Wojcieszak, R. Magnetic Nanomaterials in Catalysis:
Advanced Catalysts for Magnetic Separation and Beyond. Green Chem. 2014, 16, 2906.
(
27) Sharma, R. K.; Dutta, S.; Sharma, S.; Zboril, R.; Varma, R. S.; Gawande, M. B. Fe O (Iron
3 4
Oxide)ꢀSupported Nanocatalysts: Synthesis, Characterization and Applications in Coupling
Reactions. Green Chem. 2016, 18, 3184ꢀ3209.
(
28) Wu, W.; Changzhong, J.; Roy, V. A. Recent Progress in Magnetic Iron OxideꢀSemiconductor
Composite Nanomaterials as Promising Photocatalysts. Nanoscale 2015, 7, 38ꢀ58.
29) Gawande, M. B.; Branco, P. S.; Varma, R. S. NanoꢀMagnetite (Fe O ) as A Support for Recyclable
(
3
4
Catalysts in the Development of Sustainable Methodologies. Chem. Soc. Rev. 2013, 42, 3371ꢀ3393.
15
ACS Paragon Plus Environment

Langmuir
Page 16 of 21
(
30) Pang, F.; Zhang, R.; Lan, D.; Ge, J. Synthesis of MagnetiteꢀSemiconductorꢀMetal Trimer
Nanoparticles through Functional Modular Assembly: A Magnetically Separable Photocatalyst with
Photothermic Enhancement for Water Reduction. ACS Appl. Mater. Interfaces 2018, 10, 4929ꢀ4936.
31) Lin, F. H.; Doong, R. A. Bifunctional AuꢀFe O Heterostructures for Magnetically Recyclable
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
(
3
4
Catalysis of Nitrophenol Reduction. J. Phys. Chem. C 2011, 115, 6591ꢀ6598.
(32) Shang, L.; Liang, Y. H.; Li, M. Z.; Waterhouse, G. I. N.; Tang, P.; Ma, D.; Wu, L. Z.; Tung, C. H.;
Zhang, T. R. “Naked” Magnetically Recyclable Mesoporous AuꢀγꢀFe O Nanocrystal Clusters: A
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
3
Highly Integrated Catalyst System. Adv. Funct. Mater. 2017, 27, 1606215.
(33) Zhu, M. Y.; Wang, C. J.; Meng, D. H.; Diao, G. W. In Situ Synthesis of Silver Nanostructures on
Magnetic Fe O @ C Core–Shell Nanocomposites and Their Application in Catalytic Reduction
3
4
Reactions. J. Mater. Chem. A 2013, 1, 2118ꢀ2125.
(
(
(
34) Zhu, Z.; Lu, Z. Y.; Wang, D. D.; Tang, X.; Yan, Y. S.; Shi, W. D.; Wang, Y. S.; Gao, N. L.; Yao,
X.; Dong, H. J. Construction of HighꢀDispersed Ag/Fe O /gꢀC N Photocatalyst by Selective Photoꢀ
3
4
3
4
Deposition and Improved Photocatalytic Activity. Appl. Catal. B-Environ. 2016, 182, 115ꢀ122.
35) Wu, S. X.; He, Q. Y.; Zhou, C. M.; Qi, X. Y.; Huang, X.; Yin, Z. Y.; Yang, Y. H.; Zhang, H.
Synthesis of Fe O and Pt Nanoparticles on Reduced Graphene Oxide and Their Use as A
3
4
Recyclable Catalyst. Nanoscale 2012, 4, 2478ꢀ2483.
36) Wang, C.; Daimon, H.; Sun, S. H. DumbbellꢀLike PtꢀFe O Nanoparticles and Their Enhanced
3
4
Catalysis for Oxygen Reduction Reaction, Nano Lett. 2009, 9, 1493ꢀ1496.
(37) Li, X. Y.; Wang, X.; Song, S. Y.; Liu, D. P.; Zhang, H. J. Selectively Deposited Noble Metal
Nanoparticles on Fe O /Graphene Composites: Stable, Recyclable, and Magnetically Separable
3
4
Catalysts. Chem. Eur. J. 2012, 18, 7601ꢀ7607.
(38) Elazab, H. A.; Siamaki, A. R.; Moussa, S.; Gupton, B. F.; ElꢀShall, M. S. Highly Efficient and
Magnetically Recyclable GrapheneꢀSupported Pd/Fe O Nanoparticle Catalysts for Suzuki and Heck
3
4
CrossꢀCoupling Reactions. Appl. Catal. A-Gen. 2015, 491, 58ꢀ69.
(
(
(
39) Zubir, N. A.; Yacou, C.; Motuzas ,J.; Zhang, X. W.; Zhao, X. S.; da Costa, J. C. D. The Sacrificial
Role of Graphene Oxide in Stabilising a FentonꢀLike Catalyst GOꢀFe O . Chem. Commun. 2015, 51,
3
4
9
291ꢀ9293.
40) Yang, J.; Zhu, G. X.; Liu, Y. J.; Xia, J. X.; Ji, Z. Y.; Shen, X. P.; Wu, S. K. Fe O ꢀDecorated Co S
9 8
3
4
Nanoparticles In Situ Grown on Reduced Graphene Oxide: A New and Efficient Electrocatalyst for
Oxygen Evolution Reaction. Adv. Funct. Mater. 2016, 26, 4712ꢀ4721.
41) Atarod, M.; Nasrollahzadeh, M.; MohammadꢀSajadi, M. Green Synthesis of Pd/RGO/Fe O4
3
Nanocomposite Using Withania Coagulans Leaf Extract and Its Application as Magnetically
16
ACS Paragon Plus Environment

Page 17 of 21
Langmuir
Separable and Reusable Catalyst for the Reduction of 4ꢀNitrophenol. J. Colloid Interface Sci. 2016,
465, 249ꢀ258.
1
2
3
(
42) Zhang, C. F.; Qiu, L. G.; Ke, F.; Zhu, Y. J.; Yuan, Y. P.; Xu, G. S.; Jiang, X. A Novel Magnetic
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Recyclable Photocatalyst Based on A CoreꢀShell MetalꢀOrganic Framework Fe O @ MILꢀ100 (Fe)
3
4
for the Decolorization of Methylene Blue Dye. J. Mater. Chem. A 2013, 1, 14329ꢀ14334.
(43) Zhang, Y. F.; Qiu, L. G.; Yuan, Y. P.; Zhu, Y. J.; Jiang, X.; Xiao, J. D. Magnetic Fe O @C/Cu and
3
4
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Fe O @CuO CoreꢀShell Composites Constructed from MOFꢀBased Materials and Their
3
4
Photocatalytic Properties under Visible Light. Appl. Catal. B-Environ. 2014, 144, 863ꢀ869.
(44) Ke, F.; Wang, L. H.; Zhu, J. F. Multifunctional AuꢀFe O @ MOF Core–Shell Nanocomposite
3
4
Catalysts with Controllable Reactivity and Magnetic Recyclability. Nanoscale 2015, 7, 1201ꢀ1208.
45) Elsaidi, S. K.; Sinnwell, M. A.; Banerjee, D.; Devaraj, A.; Kukkadapu, R. K.; Droubay, T. C.; Nie,
Z. M.; Kovarik, L.; Vijayakumar, M.; Manandhar, S. Reduced Magnetism in CoreꢀShell
Magnetite@MOF Composites. Nano Lett. 2017, 17, 6968ꢀ6973.
(
(
46) Chalasani, R.; Vasudevan, S. CyclodextrinꢀFunctionalized Fe O @TiO : Reusable, Magnetic
3
4
2
Nanoparticles for Photocatalytic Degradation of EndocrineꢀDisrupting Chemicals in Water Supplies.
ACS Nano 2013, 7, 4093ꢀ4104.
(
47) Yu, X. X.; Liu, S. W.; Yu, J. G. Superparamagnetic γꢀFe O @SiO @TiO Composite Microspheres
2 3 2 2
with Superior Photocatalytic Properties. Appl. Catal. B-Environ. 2011, 104, 12ꢀ20.
(
48) Subramonia, W.; Wu, T. Y.; Chai, S. P. Photocatalytic Degradation of Industrial Pulp and Paper
Mill Effluent Using Synthesized Magnetic Fe O ꢀTiO : Treatment Efficiency and Characterizations
2
3
2
of Reused Photocatalyst. J. Environ. Manage. 2017, 187, 298ꢀ310.
(
49) Li, W.; Deng, Y.; Wu, Z.; Qian, X.; Yang, J.; Wang, Y., Gu, D.; Zhang, F.; Tu, B.; Zhao, D.
Hydrothermal Etching Assisted Crystallization: A Facile Route to Functional YolkꢀShell Titanate
Microspheres with Ultrathin NanosheetsꢀAssembled Double Shells. J. Am. Chem. Soc. 2011, 133,
1
5830ꢀ15833.
(
50) Xi, G. C.; Yue, B.; Cao, J. Y.; Ye, J. H. Fe O /WO Hierarchical CoreꢀShell Structure: Highꢀ
3
4
3
Performance and Recyclable VisibleꢀLight Photocatalysis. Chem. Eur. J. 2011, 17, 5145ꢀ5154.
(
51) Wang, L.; Wei, H. W.; Fan, Y. J; Gu, X.; Zhan, J. H. OneꢀDimensional CdS/αꢀFe O and
2
3
CdS/Fe O Heterostructures: Epitaxial and Nonepitaxial Growth and Photocatalytic Activity. J.
3
4
Phys. Chem. C 2009, 113, 14119ꢀ14125.
(
52) Shi, W.; Du, D.; Shen, B.; Cui, C. F.; Lu, L. J.; Wang, L. Z.; Zhang, J. L. Synthesis of Yolk–Shell
Structured Fe O @void@CdS Nanoparticles: A General and Effective Structure Design for Photoꢀ
3
4
Fenton Reaction. ACS Appl. Mater. Interfaces 2016, 8, 20831ꢀ20838.
17
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Langmuir
Page 18 of 21
(
53) Lin, T. R.; Wang, J.; Guo, L. Q.; Fu, F. F. Fe O @MoS Core–Shell Composites: Preparation,
3 4 2
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
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3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Characterization, and Catalytic Application. J. Phys. Chem. C 2015, 119, 13658ꢀ13664.
54) Mousavi, M.; HabibiꢀYangjeh, A. Magnetically Separable Ternary gꢀC N /Fe O /BiOI
(
3
4
3
4
Nanocomposites: Novel VisibleꢀLightꢀDriven Photocatalysts Based on Graphitic Carbon Nitride. J.
Colloid Interface Sci. 2016, 465, 83ꢀ92.
(55) Kumar, S.; Kumar, B.; Baruah, A.; Shanker, V. Synthesis of Magnetically Separable and
Recyclable gꢀC N ꢀFe O Hybrid Nanocomposites with Enhanced Photocatalytic Performance under
0
1
2
3
4
5
6
7
8
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6
7
8
9
0
1
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3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
3
4
3
4
VisibleꢀLight Irradiation. J. Phys. Chem. C 2013, 117, 26135ꢀ26143.
(56) HabibiꢀYangjeh, A.; Akhundi, A. Novel Ternary gꢀC N /Fe O /Ag CrO Nanocomposites:
3
4
3
4
2
4
Magnetically Separable and VisibleꢀLightꢀDriven Photocatalysts for Degradation of Water
Pollutants. J. Mol. Catal. A-Chem. 2016, 415, 122ꢀ130.
(
(
(
(
(
57) Lu, Z. Y.; Zhao, X. X.; Zhu, Z.; Yan, Y. S.; Shi, W. D.; Dong, H. J.; Ma, Z. F.; Gao, N. L.; Wang,
Y. S.; Huang, H. Enhanced Recyclability, Stability, and Selectivity of CdS/C@Fe O Nanoreactors
3
4
for Orientation Photodegradation of Ciprofloxacin. Chem. Eur. J. 2015, 21, 18528ꢀ18533.
58) Li, N.; Zhang, J.; Tian, Y.; Zhao, J. H.; Zhang, J.; Zuo, W. Precisely Controlled Fabrication of
Magnetic 3D γꢀFe O @ZnO CoreꢀShell Photocatalyst with Enhanced Activity: Ciprofloxacin
2
3
Degradation and Mechanism Insight. Chem. Eng. J. 2017, 308, 377ꢀ385.
59) Du, D.; Shi, W.; Wang, L. Z.; Zhang, J. L. YolkꢀShell Structured Fe O @void@TiO as A Photoꢀ
3
4
2
FentonꢀLike Catalyst for the Extremely Efficient Elimination of Tetracycline. Appl. Catal. B-
Environ. 2017, 200, 484ꢀ492.
60) Li, Q.; Meng, H.; Zhou, P.; Zheng, Y. Q.; Wang, J.; Yu, J. G.; Gong, J. R. Zn Cd S Solid
1
ꢀx
x
Solutions with Controlled Bandgap and Enhanced VisibleꢀLight Photocatalytic H ꢀProduction
2
Activity. ACS Catal. 2013, 3, 882ꢀ889.
61) Xu, X.; Lu, R. J.; Zhao, X. F.; Xu, S. L.; Lei, X. D.; Zhang, F. Z.; Evans, D. G. Fabrication and
Photocatalytic Performance of A Zn Cd S Solid Solution Prepared by Sulfuration of A Single
x
1ꢀx
Layered Double Hydroxide Precursor. Appl. Catal. B-Environ. 2011, 102, 147ꢀ156.
(62) Meng, S. G.; Ye, X. J.; Ning, X. F.; Xie, M. L.; Fu, X. L.; Chen, S. F. Selective Oxidation of
Aromatic Alcohols to Aromatic Aldehydes by BN/Metal Sulfide with Enhanced Photocatalytic
Activity. Appl. Catal. B-Environ. 2016, 182, 356ꢀ368.
(63) Chen, Y.; Zhao, S.; Wang, X.; Peng, Q.; Lin, R.; Wang, Y.; Shen, R.; Cao, X.; Zhang, L.; Zhou,
G.;Li, J.; Xia, A.; Li, Y. Synergetic Integration of Cu1.94SꢀZn Cd S Heteronanorods for Enhanced
x
1ꢀx
VisibleꢀLightꢀDriven Photocatalytic Hydrogen Production. J. Am. Chem. Soc. 2016, 138, 4286ꢀ4289.
18
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Page 19 of 21
Langmuir
(
(
(
(
64) Zhao, H.; Ding, X. L.; Zhang, B.; Li, Y. X.; Wang, C. Y. Enhanced Photocatalytic Hydrogen
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
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2
2
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3
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4
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5
5
5
5
6
Evolution along with Byproducts Suppressing over Zꢀscheme Cd Zn S/Au/gꢀC N Photocatalysts
x
1ꢀx
3
4
under Visible Light. Sci. Bull., 2017, 62,602ꢀ609.
65) Su, Y.; Zhang, Z.; Liu, H.; Wang, Y. Cd Zn S@UiOꢀ66ꢀNH Nanocomposites as Efficient and
0
.2
0.8
2
Stable VisibleꢀLightꢀDriven Photocatalyst for H Evolution and CO Reduction. Appl. Catal. B-
2
2
Environ. 2017, 200, 448ꢀ457.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
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1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
66) Hu, J. L.; Yang, Q. H.; Lin, H.; Ye, Y. P.; He, Q.; Zhang, J. N.; Qian, H. S. Mesoporous Silica
Nanospheres Decorated with CdS Nanocrystals for Enhanced Photocatalytic and Excellent
Antibacterial Activities. Nanoscale 2013, 5, 6327ꢀ6332.
67) Xu, X.; Deng, C.; Ga, M.; Yu, W.; Yang, P.; Zhang, X. Synthesis of Magnetic Microspheres with
Immobilized Metal Ions for Enrichment and Direct Determination of Phosphopeptides by Matrixꢀ
Assisted Laser Desorption Ionization Mass Spectrometry. Adv. Mater. 2006, 18, 3289ꢀ3293.
(68) Zhang, F.; Wang, W. N.; Cong, H. P.; Luo, L. B.; Zha, Z. B.; Qian, H. S. Facile Synthesis of
Upconverting Nanoparticles/Zinc Oxide Core–Shell Nanostructures with Large Lattice Mismatch for
Infrared Triggered Photocatalysis. Part. Part. Syst. Charact. 2017, 34, 1600222.
(69) Wang, W. N.; Huang, C. X.; Zhang, C. Y.; Zhao, M. L.; Zhang, J.; Chen, H. J.; Zha, Z B.; Zhao T.;
Qian H. S. Controlled Synthesis of Upconverting Nanoparticles/Zn Cd S YolkꢀShell Nanoparticles
x
1ꢀx
for Efficient Photocatalysis Driven by NIR Light. Appl. Catal. B-Environ. 2018, 224, 854ꢀ862.
70) Zhao, M. L.; Wang, W. N.; Huang, C. X.; Dong, W.; Wang, Y.; Cheng, S.; Wang, H. Q.; Qian, H.
S. Facile Synthesis of UCNPs/Zn Cd S Nanocomposites Excited by NearꢀInfrared Light for
(
x
1ꢀx
Photochemical Reduction and Removal of Cr(VI). Chin. J. Catal. 2018, 39, 1240ꢀ1248.
71) Deng, H.; Li X. L., Peng, Q.; Wang, X.; Chen, J. P; Li, Y. D. Monodisperse Magnetic Singleꢀ
Crystal Ferrite Microspheres. Angew. Chem. Int. Ed. 2005, 117, 2842ꢀ2845.
(
(
72) Chen, J.; Ding, B. B.; Wang, T. Y.; Li, F.; Zhang, Y.; Zhao, Y. L.; Qian, H. S. Facile Synthesis of
Uniform Zn Cd S Alloyed Hollow Nanospheres for Improved Photocatalytic Activities. J. Mater.
x
1−x
Sci-Mater. El. 2014, 25, 4103ꢀ4109.
(73) Gao, X. H.; Wu, H. B.; Zheng, L. X.; Zhong, Y. J.; Hu, Y.; Lou, X. W. Formation of Mesoporous
Heterostructured BiVO /Bi S Hollow Discoids with Enhanced Photoactivity. Angew. Chem. Int.
4
2 3
Ed. 2014, 126, 6027ꢀ6031.
(74) Wang, X.; Liang, Y. H.; An, W. J.; Hu, J. S.; Zhu, Y. F.; Cui, W. Q. Removal of Chromium (VI) by
A SelfꢀRegenerating and Metal Free gꢀC N /Graphene Hydrogel System via the Synergy of
3
4
Adsorption and PhotoꢀCatalysis under Visible Light. Appl. Catal. B-Environ. 2017, 219, 53ꢀ62.
19
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Page 20 of 21
(
75) Wang, H.; Jiang, S. L.; Shao, W.; Zhang, X. D.; Chen, S. C.; Sun, X. S.; Zhang, Q.; Luo, Y.; Xie,
Y. Optically Switchable Photocatalysis in Ultrathin Black Phosphorus Nanosheets. J. Am. Chem.
Soc. 2018, 140, 3474ꢀ3480.
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(
76) Zhu, Y. Y.; Wang, Y. J.; Ling, Q.; Zhu, Y. F. Enhancement of FullꢀSpectrum Photocatalytic
Activity over BiPO /Bi WO Composites. Appl. Catal. B-Environ.2017, 200, 222ꢀ229.
4
2
6
(77) Huang, H. W.; Tu, S. C.; Zeng, C.; Zhang, T. R.; Reshak, A. H.; Zhang, Y. H. Macroscopic
Polarization Enhancement Promoting Photoꢀ and PiezoelectricꢀInduced Charge Separation and
Molecular Oxygen Activation. Angew. Chem. 2017, 129, 12022ꢀ12026.
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5
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8
9
0
(78) Huang, H. W.; Li, X. W.; Wang, J. J.; Dong, F.; Chu, P. K.; Zhang, T. R.; Zhang, Y. H. Anionic
Group SelfꢀDoping as a Promising Strategy: BandꢀGap Engineering and MultiꢀFunctional
2ꢀ
Applications of HighꢀPerformance CO ꢀDoped Bi O CO . ACS Catal. 2015, 5, 4094ꢀ4103.
3
2
2
3
(79) Huang, H. W.; He, Y.; Li, X. W.; Li, M.; Zeng, C.; Dong, F.; Du, X.; Zhang, T. R.; Zhang, Y. H.
2
+
Bi O (OH)(NO ) as A Desirable [Bi O ] Layered Photocatalyst: Strong Intrinsic Polarity, Rational
2
2
3
2
2
Band Structure and {001} Active Facets CoꢀBeneficial for Robust Photooxidation Capability. J.
Mater. Chem. A, 2015, 3, 24547ꢀ24556.
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Graphic abstract
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Magnetically recyclable Fe O @Zn Cd S coreꢀshell microspheres have been fabricated successfully
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x
1ꢀx
via a facile sacrificedꢀtemplate assisted hydrothermal approach for photochemical reduction of Cr(VI)
and oxidation of organic dyes under irradiation of visible light.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
21
ACS Paragon Plus Environment