Designed synthesis of anatase-TiO2 (B) biphase nanowire/ZnO nanoparticle heterojunction for enhanced photocatalysis

Article abstract of DOI:10.1039/c7ta10274g

A high performance photocatalyst based on a heterostructure using ZnO nanoparticles (NPs) decorating mesoporous anatase-TiO₂ (B) biphase TiO₂ nanowires (NWs) was synthesized by a facile water bath reflux method. The morphology, structure, and optical properties of the prepared hybrid photocatalyst were well characterized. The results showed that the mesoporous biphase TiO₂ NWs consisted of TiO₂ (B) and anatase phases. When ZnO NPs were loaded on the surface of biphase TiO₂ NWs, a heterojunction was formed between TiO₂ NWs and ZnO NPs that could favor the separation of photogenerated electron-hole pairs. The TiO₂-ZnO heterojunction exhibited remarkably enhanced photocatalytic activity and excellent stability for both dye degradation and H₂ evolution compared with TiO₂ NWs. The heterojunction with a 20 wt% ZnO content exhibited the highest photocatalytic activity and the reaction rate constant was about 4.2 and 1.3 times higher than that of TiO₂ NWs for dye degradation and H₂ evolution, respectively. The main active species were found to be O₂^- and OH by the electron paramagnetic resonance technique. This work may open a promising avenue in producing highly efficient heterojunction photocatalysts with special structures for large-scale environmental and energy applications.

Full text of DOI:10.1039/c7ta10274g

View Article Online
View Journal
Journal of
Materials Chemistry A
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: C. Sun, Q. Xu, Y.
Xie, Y. Ling and Y. hou, J. Mater. Chem. A, 2018, DOI: 10.1039/C7TA10274G.
This is an Accepted Manuscript, which has been through the
Volume
4 Number 1 7 January 2016 Pages 1–330
Royal Society of Chemistry peer review process and has been
accepted for publication.
Journal of
Materials Chemistry A
Accepted Manuscripts are published online shortly after
Materials for energy and sustainability
www.rsc.org/MaterialsA
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 2050-7488
PAPER
Kun Chang, Zhaorong Chang et al.
Bubble-template-assisted synthesis of hollow fullerene-like
MoS2 nanocages as a lithium ion battery anode material
rsc.li/materials-a

Please do not adjust margins
Journal of Materials Chemistry A
Page 1 of 10
View Article Online
DOI: 10.1039/C7TA10274G
Journal of Materials Chemistry A
ARTICLE
Designed synthesis of anatase-TiO2 (B) biphase nanowires/ZnO
nanoparticles heterojunction for enhanced photocatalysis
Chaoyang Sun,a Qiuhua Xu,a Yu Xie,*,a Yun Linga and Yang Hou*,b,c
Received 00th January 20xx,
Accepted 00th January 20xx
A high performance photocatalyst based on heterostructure using ZnO nanoparticles (NPs) decorating mesoporous
anatase−TiO2 (B) biphase TiO2 nanowires (NWs) was synthesized by a facile water bath reflux method. The morphology,
structure, and optical property of the prepared hybrid photocatalyst were well characterized. The results showed that the
mesoporous biphase TiO2 NWs consisted of TiO2 (B) and anatase phase. When ZnO NPs was loaded on the surface of
biphase TiO2 NWs, a heterojunction was formed between TiO2 NWs and ZnO NPs that could favor the separation of
photogenerated electron-hole pairs. The TiO2-ZnO heterojunction exhibited remarkably enhanced photocatalytic activity
and excellent stability for both the dyes degradation and H2 evolution compared with those of TiO2 NWs. The
heterojunction with a 20 wt.% ZnO content exhibited the highest photocatalytic activity and the reaction rate constant
was about 4.2 and 1.3 times higher than that of TiO2 NWs for dye degradation and H2 evolution, respectively. The main
active species were found to be O2•- and •OH by electron paramagnetic resonance technique. This work may open a
promising venue in producing highly-efficient heterojunction photocatalyst with special structure for large-scale
environment and energy applications.
DOI: 10.1039/x0xx00000x
www.rsc.org/
1. Introduction
semiconductors,18-22 and surface sensitization,23 etc. Among
them, coupling photocatalyst with metal oxides such as CuO,24
ZnO,25 and NiO26 has been demonstrated to be an effective
approach to promote the separation efficiency of
photoelectrons from vacancies, and thus enhance the overall
photocatalytic activity.27
Environmental pollution and clean energy have become the
main factors that influence the global sustainable
development.1, 2 Many efforts are being taken to develop more
green and effective technologies to address these issues. The
utilization of semiconductors for applications in photocatalytic
pollutant degradation and H2 production from water splitting
has received much attention due to advantages of clean, low-
cost, and environmentally friendly operation.3-5 Titanium
dioxide (TiO2), one of the most promising photocatalytic
material, has attracted arising extensive and long lasting
attention owing to its excellent photocatalytic performance,
Recently, ZnO has been reported to be a promising optical and
electronic material due to its wide band-gap of 3.37 eV and
large exciton binding energy of 60 meV,28 and widely used in
the fields of photocatalysts, rechargeable lithium-ion batteries,
gas sensors, and electrodes in solar cells.29-32 Besides the
similar band edge energy with TiO2, ZnO possesses some
distinctive advantages such as longer life time of
photogenerated carriers, higher quantum yield, and higher
electron mobility than that of TiO2,33, 34 which are favorable for
the enhancement of photocatalytic activity. In addition, the
properties of easy crystallization and anisotropic growth allow
ZnO to be synthesized in a variety of nanostructures.35
Importantly, the valence band position and energetic
conduction of ZnO are favorable for the H2 evolution from
water splitting, and the band level of ZnO matches well with
TiO2.36 Therefore, it is a promising way to enhance the
photocatalytic performance for pollutant degradation and H2
production by coupling ZnO with nanostructured TiO2.
high chemical stability, non-toxicity, and low cost.6,
7
Nevertheless, wide band-gap (3.2 eV) of TiO2 makes it only
respond to ultraviolet light that accounts for only around 5% of
the solar spectrum.8, Meanwhile, the recombination of
9
photogenerated electron-hole pairs is another reason for the
decrease in photocatalytic efficiency.10 To date, various
strategies have been developed to improve the photocatalytic
performance of TiO2, including doping TiO2 with metal11-13 and
non-metal
elements,14-17
coupling
with
other
a.Nanchang Hangkong University, Department of Material Chemistry, Nanchang,
Jiangxi Province, China. *E-mail: xieyu_121@163.com
Since Iijima et al.37 discovered carbon nanotubes in 1991, one
dimensional (1D) nanomaterials, such as nanowires (NWs),
nanotubes, nanorods, and nanofibers, have attracted much
attention due to their distinctive advantages. TiO2 NWs have a
b.Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College
of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027,
China. *E-mail: yhou@zju.edu.cn
c. Department of Chemistry and Food Chemistry & Center for Advancing Electronics,
Dresden (CFAED), Technische Universitaet Dresden, 01062 Dresden, Germany.
high aspect ratio with
a length reaching hundreds of
†
Electronic Supplementary Information (SI) available. See DOI:
micrometers, which make it suitable to possess a relatively
10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
Journal of Materials Chemistry A
Page 2 of 10
ARTICLE
Journal Name
large specific surface area and easy transfer of photogenerated Ltd, purity > 96.0%) solution. After being ultrasonicated for 30
View Article Online
electrons along the axial direction.38 Furthermore, the min, the mixture was kept under magnetic stirring for 30 min.
DOI: 10.1039/C7TA10274G
advantages of TiO2 NWs, such as higher chemical stability and Afterward, the mixture was transferred into a 100 mL Teflon-
lower photogenerated carrier recombination rate than those lined autoclave, which was further placed in an electric oven at
of TiO2 nanoparticles (NPs), make it widely used in 200 °C for 24 h. After naturally cooling in air, the product was
photodegradation and photocatalytic H2 evolution from water harvested by centrifugation, and then washed with deionized
40
splitting.39,
Therefore, it is believed that the TiO2 NWs water for several times until the pH of supernatant reached to
coupled with ZnO to form a heterojunction will possess 7.0. Then, the obtained precipitate was dispersed in 0.1 mol L-1
excellent photocatalytic properties. nitric acid (Cangzhou Longsheng Chemical Co., Ltd) solution
Anatase, rutile, and brookite are the most common phases of with continuous stirring for 5 h. After that, the product was
TiO2, which play important roles in photocatalytic activity. The collected via centrifugation, and washed with deionized water,
TiO2 (B) phase, discovered in late 1980s by Marchand et al.,41 is and then dried in a vacuum oven at 80 °C for 24 h. Finally, the
a metastable phase with a loose structure and a lower density obtained sample was calcined at 500 °C for 3 h with a heating
than that of anatase and rutile. During the past few decades, rate of 5 °C min-1.
TiO2 (B) has attracted much interest in the applications of ZnO NPs loaded biphase TiO2 NWs heterojunction was synthesized
rechargeable lithium-ion storage, sensor, and photocatalysis.42, by a reflux method. Typically, a certain amount of TiO2 NWs was
43
Shen et al.44 found that the formed Ti3+ and oxygen dispersed in 62.5 mL of 0.01 M Zn(CH3COO)2/methanol solution.
vacancies in TiO2 (B) can enhance solar light absorption, thus After vigorous stirring, the mixture was kept under ultrasonic
improving the photocatalytic properties. Moreover, compared treatment for 30 min to obtain the uniform solution. Next, 32.5 mL
with single phase TiO2, mixed phase TiO2 can exhibit much of 0.03 M NaOH was added into the solution with strong stirring,
higher photocatalytic activity than either of the component. followed by reflux at 6 h in 60 °C. Subsequently, the sample was
For example, the commercial P25 (Degussa) that consists of collected by centrifugation, washed with deionized water and
anatase (~80%) and rutile (~20%), possesses higher methanol, and then dried in a vacuum oven at 80 °C for 24 h. The
photocatalytic activity than that of pure anatase or rutile,45 weight percentages of ZnO in the hybrid photocatalysts were 0, 10,
which may be due to the fast interfacial electron transfer 15, 20, 30, 50, and 70 wt.%, and the resulting samples were labeled
caused by difference between the conduction band edges of as TiO2-ZnO-x, where x = 0, 10, 15, 20, 30, 50, and 70, respectively.
two phases, thus increasing charge separation efficiency. 2.2. Materials Characterization
Although the photocatalytic activity of TiO2 (B) is much lower X-ray diffraction (XRD) measurement of the products was recorded
than that of anatase, the existence of difference between on a Rigaku RINT 2000 Advance X-ray diffractometer (Cu Kα
anatase and TiO2 (B) can improve the charge separation radiation, λ=1.5406 Å). Raman spectra were obtained on a laser
efficiency when the two phases are in contact with each Raman spectrometer with a back-scattering configuration using an
other.46, 47 It has been well established in the literatures that Ar+ laser (20 mW, 532 nm) as excitation source. The morphology of
TiO2 photocatalyst with the mixed phase of anatase and TiO2 the samples was examined with a JEOL JSM-6700F Field emission
(B) exhibited superior photoactivity as compared to pure scanning electron microscopy (FESEM) in a secondary electron
46, 47
anatase and TiO2 (B) catalyst.43,
Therefore, the scattering mode at 15 kV. The morphology and lattice structure was
Tecnai G2F20 S-Twin instrument at an
for pollutant degradation and H2 evolution is actively being accelerating voltage of 200 kV. The UV-Vis absorption spectra of the
pursued. samples were recorded using an Evolution 220 UV-Vis
construction of ZnO/biphase TiO2 (B)/anatase heterojunction characterized by
a
In this work, a biphase anatase/TiO2 (B) NWs was synthesized spectrophotometer (Thermo Fisher) from 200 to 800 nm, using
by a hydrothermal, ion exchange, and calcination of P25, and BaSO4 powder as the substrate. The Brunauer–Emmett–Teller (BET)
then the ZnO NPs was decorated on the biphase anatase/TiO2 surface area and pore structure of the samples were measured with
(B) NWs to form a TiO2-ZnO heterojunction by a simple reflux a NOVA 2000e (Quantachrome). The surface composition and
method. The as-prepared hybrid photocatalyst exhibited a chemical state were analyzed by an ESCALAB MK II X-ray
significant improvement in photocatalytic degradation and H2 photoelectron spectrometer (XPS) with a Mg Kα (1253.6 eV) as the
evolution from water splitting, thanks to the heterojunction excitation source. All the binding energy values in the XPS spectra
formed at the interface of TiO2-ZnO that reduced the were calibrated using carbon contaminant (C 1s: 284.6 eV) as
recombination of photoinduced charge carriers, ultimately reference.
improving the photocatalytic efficiency.
2.3. Photoelectrochemical (PEC) measurements
PEC measurements were carried out using
a CHI 660D
electrochemical workstation in a conventional three electrode
system. The TiO2 and ZnO/TiO2 electrodes were employed as the
working electrode. Ag/AgCl electrode and glassy carbon electrode
served as the reference and counter electrodes, respectively. 0.5 M
sodium sulfate was used as the electrolyte solution (pH = 7.0). A
300 W Xe lamp (PLS-SXE300, Perfect Light Company, Beijing, China)
was utilized as the light source. To prepare the working electrode,
10 mg TiO2 or ZnO/TiO2 sample was dispersed into 1 mL deionized
2. Experimental
2.1. Materials preparation
Biphase TiO2 NWs was prepared according to the precious
reports with slight modifications.48 All chemicals were of
analytical grade and used without further purification. 2.0 g
P25 (Beijing Entrepreneur Science & Trading Co., Ltd) was
dispersed into 80 mL of 10 M NaOH (West Long Chemical Co.,
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 10
Journal of Materials Chemistry A
Please do not adjust margins
Journal Name
ARTICLE
water, respectively. Then, the suspension was dip-coated onto the weakened obviously, and when the content of ZnO NPs exceeds
View Article Online
DOI: 10.1039/C7TA10274G
surface of fluorine tin oxide (FTO) glass substrates (2 cm × 2 cm), 20%, the (001) plane of TiO2 (B) is vanished.
and dried at room temperature. Electrochemical impedance spectra
(EIS) of the samples were obtained in a 0.1 M KCl solution.
2.4. Photocatalytic activity measurements
Photocatalytic activity of the samples was evaluated by degradation
of MO, MB, RhB, and phenol. A 300 W Xe lamp (PLS-SXE300, Perfect
Light Company, Beijing, China) was used as the light source. The
light intensity was 100 mW cm-2. The distance between light source
and the surface of reaction solution was set at 15 cm. 10 mg of
photocatalyst was dispersed in an aqueous solution of MO (50 mL,
10 mg L-1), RhB (50 mL, 10 mg L-1), MB (50 mL, 10 mg L-1),
respectively, and 50 mg of photocatalyst was dispersed in an
aqueous solution of phenol (50 mL, 10 mg L-1). Prior to the
irradiation, the mixtures were magnetically stirred for 30 min in
dark to reach the adsorption-desorption equilibrium between the
samples and model pollutants. At a given time interval, aliquots (3
mL) of the solution were sampled and subsequently centrifuged to
remove the photocatalysts. The concentration was monitored by
measuring the maximum absorbance at 463 nm for MO, 554 nm for
RhB, 664 nm for MB, and 269 nm for phenol through a UV-Vis
spectrophotometer (UV-2550, Shimadzu, Japan).
Fig. 1. XRD patterns of (a) TiO2 NWs, (b) TiO2-ZnO-10, (c) TiO2-ZnO-20, (d) TiO2-ZnO-30,
and (e) TiO2-ZnO-50.
Raman measurements were completed to further characterize the
crystal structure of the TiO2 NWs and TiO2-ZnO samples. The Raman
spectra of the TiO2 NWs exhibit a small shift to the lower frequency
compared with the previous results,49, 50 which could mainly be
attributed to the size effect and special nanostructure. For the TiO2-
ZnO samples, the peaks at 119, 236, and 248 cm-1 can be assigned
to the vibration of TiO2 (B), while the peaks at 141, 195, and 636 cm-
1 are attributed to the Eg vibration of anatase (Fig. 2). No obvious
ZnO peaks are observed in the hybrid. Raman analysis further
confirms the presence of TiO2 (B) and anatase, which are the main
phases in the hybrid samples, consistent with the XRD results.
Photocatalytic H2 evolution tests were carried out in a double
jacketed British purple glass reactor with a flat optical window at
room temperature. The experiments were conducted by dispersing
50 mg of photocatalyst in an aqueous solution containing 72 mL of
deionized water and 8 mL of methanol used as the sacrificial
reagent. Prior to the reaction, the mixture was thoroughly stirred to
ensure that the photocatalyst was well distributed into the solution.
The system was completely vacuumed to remove CO2 and O2
dissolved in water. A 300 W Xeon-lamp was used as the light source.
The H2 evolution was measured using an on-line gas
chromatography (GC) with the interval of 0.5 h each (Huaai GC9560,
TCD, China).
3. Results and discussion
X-ray diffraction (XRD) analysis was conducted to investigate the
crystalline structure of the resulted materials. Fig. 1 shows the XRD
patterns of TiO2 NWs and TiO2-ZnO samples. The TiO2 NWs are
mainly composed of anatase and TiO2 (B) phases. The strongest
peak at around 25.2° and the other peaks at 37.8, 53.9, 55.1, 62.6°
correspond to the (101), (004), (105), (211), and (204) crystal planes
of anatase TiO2 (JCPDS 21-1272), whereas the peaks at 14.2, 28.6,
29.7, 29.9, 33.2, 43.5, 44.5, and 48.4° match well with the (001),
(002), (401), (111), (310), (003), (601), and (020) crystal planes of
TiO2 (B) (JCPDS 46-1237). After coupling with ZnO NPs, the
characteristic peaks for TiO2 NWs and ZnO NWs are observed. From
Fig. 1b, the peaks at 31.7, 34.4, 36.2, 47.54, 56.5, and 67.9° can be
indexed as the (100), (002), (101), (102), (110), and (112) diffraction
planes of ZnO with a wurtzite structure (JCPDS 89-1397). It is clearly
seen that the loading amount of ZnO NPs has a great influence on
the composition of TiO2 crystal phase. The phases of TiO2 NWs are
mainly composed of TiO2 (B) and relatively few anatase. However,
with an increase of loading amount of ZnO NPs, the peaks
intensities of TiO2 (B) decrease gradually. When the content of ZnO
NPs is up to 20%, the peaks intensities of TiO2 (B) become
Fig. 2. Raman spectra of (a) TiO2 NWs, (b) TiO2-ZnO-10, (c) TiO2-ZnO-20, (d) TiO2-ZnO-
30, and (e) TiO2-ZnO-50.
FESEM measurements were conducted to investigate the
surface morphologies of TiO2 NWs and TiO2-ZnO samples. The
FESEM images in Fig. S1a shows that the TiO2 NWs possess a
typical 1D structure with a diameter of
～ 50 nm and a length
of 4 µm. Fig. S1b-e exhibit the morphology of ZnO NPs
～
modified TiO2 NWs with different loading amounts. It can be
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Journal of Materials Chemistry A
Page 4 of 10
ARTICLE
Journal Name
clearly seen that the ZnO NPs is spherical nanoparticles with a energy edge of the VB at about 2.66 and 2.65 eVV,ierwesAprteiccletiOvnelilnye,
diameter of
20 nm, which is uniformly dispersed on the which are consistent with the estimated valuDeOs.I: 10.1039/C7TA10274G
～
surface of TiO2 NWs. For the TiO2-ZnO-50 sample (Fig. S1d),
most of the ZnO NPs were accumulated on the surface of TiO2
NWs, which could lead to a decrease in photocatalytic activity.
The energy-dispersive X-ray spectroscopy (EDS) and elemental
mappings of the TiO2-ZnO-20 sample prove the existence of Ti,
O, and Zn elements in the hybrid (Fig. S1f-i).
TEM and high resolution TEM (HRTEM) measurements were
conducted to investigate the microstructures of the TiO2-ZnO-20
sample, and the results are shown in Fig. S2a-d. The TiO2 NWs
shows a uniform wire-like morphology with a rough surface; lots of
ZnO NPs with a size of about 20 nm are attached on the surface of
TiO2 NWs. As shown in the HRTEM images (Fig. S2c-d), the lattice
spacings of the TiO2 NWs are 0.24, 0.35, and 0.38 nm, respectively,
corresponding to the (001) and (101) crystal planes of anatase, as
well as the (111) crystal plane of TiO2 (B), which is well consistent
with XRD results that the TiO2 NWs was composed of TiO2 (B) and
anatase. The lattice spacing of ZnO NPs is about 0.26 nm,
corresponding to the (002) plane of hexagonal wurtzite ZnO. The
distinct and continuous fringe suggests the high crystallinity of the
hybrid photocatalyst. Moreover, the circled zone in Fig. S2d shows
that the interface between ZnO NPs and TiO2 NWs is likely formed
by epitaxial growth, which results in a strong interaction between
ZnO and TiO2. The strong interaction between them may be due to
the fact that the lattice spacing of (101) plane for anatase is 0.35
nm which is close to the a and b values (a = b = 0.32 nm)51 of the
lattice parameters of hexagonal wurtzite ZnO. This match between
the lattice parameters makes it easy to form a heterojunction
between ZnO NPs and TiO2 NWs.52
The optical properties of TiO2 NWs and TiO2-ZnO samples were
investigated by UV-Vis diffuse reflectance spectroscopy (Fig. 3a).
The absorption edge of TiO2 NWs is estimated to be 470 nm. For the
TiO2-ZnO samples with different loading amounts, a slightly red shift
of the absorption edges is observed compared with that of TiO2
NWs. Thus, the TiO2-ZnO samples can effectively extend the photo-
responses of TiO2 NWs into the visible spectrum, leading to the
improvement of solar light utilization efficiency.
The band gap energies (Eg) are calculated from the Kubelka–Munk
function plots of (ahν)1/2 versus energy (hν) (Fig. 3b), where “a” and
“hν” are the optical absorption coefficient and photonic energy,
respectively. The Eg of TiO2 NWs and TiO2-ZnO-20 sample are
determined to be 2.99 and 2.96 eV, respectively. The valence bands
(VB) of TiO2 NWs and TiO2-ZnO-20 sample can be estimated by the
following empirical equation:53
Fig. 3. (a) Optical absorption spectroscopy and (b) band gap of TiO2 NWs, TiO2-ZnO-10,
TiO2-ZnO-15, TiO2-ZnO-20, TiO2-ZnO-30, and TiO2-ZnO-50.
XPS measurements were used to investigate the surface
composition and the chemical state of the TiO2 NWs and TiO2-ZnO-
20 sample. Fig. S3 shows the XPS survey spectra and high-resolution
XPS spectra of Ti 2p, Zn 2p, and O 1s regions for the TiO2-ZnO-20
sample. The survey spectra of the TiO2 NWs and TiO2-ZnO-20
sample further indicate the presence of Ti, Zn, O, and C elements in
the TiO2 NWs and TiO2-ZnO-20 sample (Fig. S3a). Fig. S3b exhibits
the high-resolution Ti 2p spectra of the TiO2 NWs and TiO2-ZnO-20
sample. In the Ti 2p spectra, the existence of Ti (IV) in the TiO2-ZnO-
20 sample is evidenced by a main peak located at 458.4 eV, slightly
shifting of 0.1 eV towards the lower binding energy as compared to
that of TiO2 NWs (458.5 eV), which can be assigned to Ti 2p3/2. And
the higher binding energy at 464.2 eV is assigned to Ti 2p1/2. The
high-resolution Zn 2p spectra of the TiO2-ZnO-20 sample (Fig. S3c)
exhibit two contributions, Zn 2p1/2 and Zn 2p3/2, located at 1,021.5
and 1,044.6 eV, respectively, indicating that the Zn exists in the
form of Zn2+. The high-resolution O 1s spectra of the TiO2-ZnO-20
sample in Fig. S3d can be fitted into two peaks. The main peak at
529.9 eV indicates that the O is in the form of O2-. And the higher
binding energy at 531.7 eV assigned to the -OH group on the
surface of the TiO2-ZnO-20 sample, shows an apparent shift of 0.2
eV towards the higher binding energy in contrast with that of TiO2
NWs (531.5 eV).
EVB = X – Ee + 0.5 Eg
ECB = EVB – Eg
(1)
(2)
X is the electronegativity of the semiconductor, and the value is
5.66 eV for TiO2. Ee is the energy of free electron on the hydrogen
scale ( ～ 4.5 eV), and Eg is the band gap energies of the
semiconductor, which can be calculated to be 2.99 eV for the TiO2.
Thus, the EVB of TiO2 NWs and TiO2-ZnO-20 sample are calculated to
be 2.66 and 2.64 eV, and the ECB of TiO2 NWs and TiO2-ZnO-20
sample are calculated to be -0.33 and -0.32 eV, respectively.
Meanwhile, XPS valence spectra were used to determine the VB of
TiO2 NWs and TiO2-ZnO-20 sample, and the results are shown in Fig.
S3e-f. The TiO2 NWs and TiO2-ZnO-20 sample show the maximum
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 10
Journal of Materials Chemistry A
Please do not adjust margins
Journal Name
ARTICLE
The transient photocurrent tests were carried out to investigate the surface area is the most suitable candidate for photocatalytic
View Article Online
DOI: 10.1039/C7TA10274G
separation efficiency of the photogenerated electrons and holes reaction. The Nitrogen adsorption-desorption isotherms and pore
pair of the as-prepared photocatalysts, and the results are shown in size distributions of the TiO2 NWs and TiO2-ZnO samples are shown
Fig. 4. For the TiO2 NWs and TiO2-ZnO samples, upon the light in Fig. 5. In Fig. 5a, the TiO2 NWs shows a typical type-IV isotherm
irradiation, the transient photocurrent is generated and then with a type H3 hysteresis loop at high relative pressure (P/P0 = 0.6-
photocurrent density increases sharply. Subsequently, the 1.0), suggesting the existence of mesoporous structure. The
photocurrent density decreases rapidly to zero when the irradiation samples of TiO2-ZnO-20 and TiO2-ZnO-50 display similar isotherms
is stopped. Clearly, the TiO2-ZnO-20 sample exhibits the highest as the TiO2 NWs, indicating that the ZnO NPs loaded on the TiO2
photocurrent density among all of the measured samples. The NWs has a minor impact on the mesoporous structure of TiO2 NWs.
photocurrent density of 2.2 μA cm-2 for TiO2-ZnO-20 sample was The corresponding pore size distribution curves are shown in Fig.
more than twice as high as that of the TiO2 NWs (0.9 μA cm-2). The 5b. The pore size distribution curve of the TiO2-ZnO-20 sample
enhanced photocurrent response of the TiO2-ZnO-20 sample shows a broad peak, indicating the existence of different grades of
indicates that the coupling ZnO with TiO2 is an efficient way to porous structure, including the small mesopores of 10 nm and large
promote the separation of photogenerated electrons and holes.
mesopores of 20 nm, which are consistent with the TEM analysis.
EIS measurement was used to investigate the charge transfer These different grades of porous structure are mainly originated
resistance and the separation efficiency of the photo-generated from the nonuniform space between the packed NPs and existence
electrons and holes. Fig. S4 shows the EIS Nynquist plots of TiO2 of mesopores with different sizes on the surface of TiO2 NWs. Such
NWs and TiO2-ZnO samples before and after light irradiation. The a hierarchical porous structure and high specific surface area of the
arc radius of the TiO2-ZnO-20 sample is the smallest among all of TiO2-ZnO hybrid can not only increase the contact area of the
the samples under light irradiation, indicating that the TiO2-ZnO-20 reactant molecules and catalyst surface, but also provide more
sample has the lowest electron-transfer resistance. The results favorable reaction sites in the process of adsorption and
demonstrate that the loading of ZnO NPs onto the surface of TiO2 photocatalytic reaction, thus improving photocatalytic efficiency.
NWs can efficiently promote the separation of photogenerated
charge carriers through an interfacial interaction between ZnO and
TiO2, which is an agreement with the transient photocurrent
responses of these photocatalysts.
Fig. 4. Transient photocurrent responses of the TiO2 NWs and TiO2-ZnO samples.
Nitrogen physical adsorption was used to investigate the textural
properties of the TiO2 NWs and TiO2-ZnO samples. The BET specific
surface area, total pore volume, and average pore diameter of the
TiO2 NWs and TiO2-ZnO samples are shown in Table S1. The BET
specific surface area of TiO2 NWs is calculated to be 21.94 m2 g-1,
the average pore diameter and pore volume are 17.08 nm and
0.094 cm3 g-1, respectively. When the ZnO NPs are introduced onto
TiO2 NWs, the BET specific surface area firstly increases to 23.29 m2
g-1 for the TiO2-ZnO-20 sample, and then decreases to 22.16 m2 g-1
Fig. 5. Nitrogen adsorption–desorption isotherm of the TiO2-ZnO samples with different
loading amounts (a) and the corresponding pore size distributions curves (b).
with further increasing the loading amount of ZnO NPs to 50 wt.%,
which can be attributed to the fact that a partial reunion
phenomenon is occurred when the loading excessive ZnO NPs on
The photocatalytic performance of TiO2-ZnO samples was evaluated
the surface of TiO2 NWs.54 The agglomeration causes the decrease
by the degradation of MO, as shown in Fig. 6a. There is almost no
in BET specific surface area of hybrid photocatalysts. Among all of
degradation of MO after 80 min irradiation in the absence of
the samples, the TiO2-ZnO-20 sample with the highest BET specific
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
Journal of Materials Chemistry A
Page 6 of 10
ARTICLE
Journal Name
photocatalyst, indicating that the MO molecules are sufficiently
stable under UV-Vis light irradiation and its self-photolysis can be
ignored in the photocatalytic process. 79.6% of MO is degraded
over the pristine ZnO NPs after 50 min irradiation. And this
percentage is further increased to be 97.7% over the TiO2-ZnO-20
sample. As for the TiO2 NWs, it shows a weak photocatalytic
activity, and ～ 31% of MO is decomposed after 80 min
irradiation. After coupling with ZnO NPs, the photocatalytic activity
of TiO2-ZnO hybrids firstly increases monotonously with the mass
ratio of ZnO NPs increases from 10 wt.% to 20 wt.%, and then
decreases with further increase of ZnO NPs content. Therefore, the
20 wt.% ZnO content in the TiO2-ZnO samples is found to be the
best loading ratio for MO degradation. The result suggests that the
heterojunctions should be formed between ZnO NPs and TiO2 NWs,
which play crucial role in the separation and transfer of photo-
generated charge carriers. Under the UV-Vis light irradiation, the
generated electrons in the TiO2 NWs and ZnO NPs could be excited
from the valence band (VB) to the conduction band (CB). Due to the
difference of CBs, the photo-generated electrons in the CB of
anatase and ZnO can easily transfer to the TiO2 (B), resulting in the
efficient separation and reduced possibility of the recombination of
photogenerated electron-hole pairs.
View Article Online
DOI: 10.1039/C7TA10274G
To better compare the photocatalytic performance of these
samples, the reaction kinetics of MO degradation is investigated.
Fig. 6b presents the linear fitting of the degradation time against –
ln (C/C0), and the reaction rate constants (k) are given in Table S2.
Obviously, the degradation process of MO follows the pseudo-first-
order kinetics, and the TiO2-ZnO-20 sample has the maximum k
value of 0.0420 min-1, which is almost 4.2 times as high as that of
TiO2 NWs.
Fig. 6. (a) Photocatalytic degradation of MO in the presence of TiO2 NWs and TiO2-ZnO
samples, and (b) kinetic fit for the degradation of MO with the TiO2 NWs and TiO2-ZnO
samples.
To further investigate the degradation of dyes with different
structures, RhB and MB were also used to evaluate the
photocatalytic activity of the as-prepared TiO2-ZnO samples. As
shown in Fig. 7a-b, upon light irradiation, the concentration of RhB
and MB decreases gradually as the reaction time increases. The
TiO2-ZnO-20 sample exhibits excellent photocatalytic performance
for the degradation of RhB and MB than those of TiO2 NWs.
Considering the obvious structural difference of the three dyes, it
turns out that the TiO2-ZnO hybrid has the universal application on
degradation of dyes.
For comparison, the phenol was selected as a different kind of
model pollutant to further ascertain the photocatalytic
performance of the TiO2-ZnO samples. As shown in Fig. 7c, the TiO2-
ZnO-20 sample shows a much higher photocatalytic performance
than that of TiO2 NWs. Fig. 7d exhibits a temporal evolution of the
UV-Vis absorption of phenol solution degraded by the TiO2-ZnO-20
sample. The intensity of the characteristic absorption peak at about
269 nm decreases gradually and about 99% phenol is degraded over
TiO2-ZnO-20 sample after 2 h irradiation. Based on this result, it can
be reasonable to conclude that the MO, MB, and RhB degradation
over TiO2-ZnO samples are mainly attributed to the photocatalysis
process of TiO2-ZnO samples rather than the photosensitization
effect of the dyes.
Fig. 7. Photocatalytic degradation of RhB (a), MB (b), and phenol (c) in the presence of
TiO2 NWs and TiO2-ZnO-20 sample under light irradiation. (d) UV-Vis absorption
spectral changes during the photocatalytic degradation of phenol in aqueous solution
in the presence of the TiO2-ZnO-20 sample.
In order to identify the active species over the TiO2-ZnO samples,
the EPR spin-trap experiments with 5,5-dimethyl-1-pyrroline N-
oxide (DMPO) were carried out under light irradiation, and the
results are shown in Fig. 8. The characteristic peaks from the
DMPO-O•2− species can be observed in the dispersion of TiO2-ZnO-
20 sample, and the characteristic peaks of DMPO-•OH can also be
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 10
Journal of Materials Chemistry A
Please do not adjust margins
Journal Name
ARTICLE
obviously observed in the irradiated suspension. The intensity of
DMPO-O•2− signal is higher than that of DMPO-•OH signal, which
indicates that the O•2− radicals may play a more important role
than •OH radicals during the photodegradation process.
View Article Online
DOI: 10.1039/C7TA10274G
Fig. 9. Cycling performance of the TiO2-ZnO-20 sample for MO degradation.
In order to further investigate the photocatalytic properties of as-
prepared TiO2-ZnO samples, additional experiments were carried
out for photocatalytic H2 evolution in the presence of 1 wt.% Pt co-
catalyst. Fig. 10a shows the total H2 evolution by TiO2 NWs and the
TiO2-ZnO samples. The TiO2-ZnO-20 sample displays the highest H2
evolution among these samples at every 30 min. Fig. 10b shows the
H2 generation rate of TiO2 NWs and all of the TiO2-ZnO samples. The
H2 generation rate of the samples is relatively stable. The H2
generation rate of the TiO2 NWs, TiO2-ZnO-10, TiO2-ZnO-15, TiO2-
ZnO-20, TiO2-ZnO-30, TiO2-ZnO-50 samples are 145, 134, 181, 193
172, and 155 µmol h-1 g-1, respectively. The results indicate that the
TiO2-ZnO-20 sample has the highest photocatalytic activity among
these samples and its H2 generation rate is about 1.3 times as much
as that of TiO2 NWs, revealing that the heterojunction structure is
helpful to enhance the photocatalytic performance.
Based on the above results, a possible photocatalytic mechanism is
proposed to explain the enhancement of the photocatalytic activity
of TiO2-ZnO heterostructure (Fig. 11). The TiO2-ZnO photocatalyst is
believed to exhibit cooperative or synergic effects among anatase,
TiO2 (B), and ZnO NPs. When the TiO2-ZnO samples are irradiated by
UV-Vis light, the photogenerated electrons in the VB of ZnO NPs
and anatase−TiO2 (B) biphase TiO2 NWs can be excited to the CB of
ZnO NPs and anatase−TiO2 (B) biphase TiO2 NWs, respectively.
Then, the photogenerated electrons on the CB of ZnO NPs and TiO2
(B) are transferred to the CB of anatase,46 while the holes are
transferred from the anatase and TiO2 (B) to ZnO NPs due to the
existence of energy gradient at the interface between ZnO, anatase,
and TiO2 (B). This process results in an effective separation of active
photogenerated electrons and holes, thus increasing the lifetime of
the charge carriers and hence improving the photocatalytic activity.
The separated photogenerated electrons can reduce the H2O to H2,
and the holes can oxidize the organic compounds to CO2 and H2O.
As a consequence, the enhanced charge separation and transfer
induces the superior photocatalytic activity of the heterostructured
ZnO NPs/mesoporous anatase−TiO2 (B) biphase TiO2 nanowires
heterojunction.
Fig. 8. EPR spectra of radical adducts trapped by DMPO in TiO2-ZnO samples: (a)
methanol dispersion and (b) aqueous dispersion under UV-Vis light irradiation.
In the photocatalytic reaction, the stability and repeatability of the
photocatalyst are important factors affecting the photocatalytic
efficiency. In order to get insights into the cycling stability, the TiO2-
ZnO-20 sample was used to test the recycling performance of
photocatalyst. In our test, 60 mg of photocatalyst was added into
the 30 mL of MO solution (10 mg L-1), and then the mixture was
magnetically stirred for 30 min in dark to reach the adsorption-
desorption equilibrium between the powder sample and model
pollutant. After 1 h light irradiation, the sample was collected by
centrifugation and used for the next reaction. The experimental
results are shown in Fig. 9. It is clear to see that the TiO2-ZnO-20
sample still maintain the high activity even in the photocatalytic
degradation experiment for 5 times. The results suggest that the
structure of the as-prepared TiO2-ZnO sample wis stable, reusable
and hard to inactivate.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins

Please do not adjust margins
Journal of Materials Chemistry A
Page 8 of 10
ARTICLE
Journal Name
In this work, we developed a simple solution syntheVsiieswmAretictlheoOdnlitnoe
prepare a heterojunction photocatalyst oDf OZI:n1O0.1N03P9s/Cd7eTcAo10ra2t7i4nGg
biphase TiO2 NWs. The as-prepared TiO2-ZnO hybrid presents
appreciable photocatalytic performance in pollutant degradation as
well as H2 evolution, which can be mainly attributed to their
constructed wire-like morphology, multiphase structure, high BET
surface area, and heterojunction built. It is promising that this
material can be further used in the fields of rechargeable lithium-
ion batteries, gas sensors, and electrodes in solar cells.
Acknowledgements
This work was financially supported by the National Natural Science
Foundation of China (No.21667019), the Key Project of Natural
Science Foundation of Jiangxi Province (No.20171ACB20016), the
Jiangxi Province Major Academic and Technical Leaders Cultivating
Object Program (No.20172BCB22014), the Key Laboratory of
Photochemical Conversion and Optoelectronic Materials, TIPC, CSA
(No.PCOM201401) and Key Project of Science and Technology
Research of Jiangxi Provincial Department of Education
(No.DA201602063). Financial support for this work was further
provided by the Fundamental Research Funds for the Central
Universities (112109*172210171), the Start-up Foundation for
Hundred-Talent Program of Zhejiang University (112100-
193820101/001/022), and National Natural Science Foundation of
China (No.51702284).
Supporting Information
Supplementary data associated with this article can be found, in the
online version.
Fig. 10. H2 evolution from water splitting over TiO2 NWs, and TiO2-ZnO samples by using
methanol as an electron donor.
References
[1] J. Zhao, Q. Lu, C. Wang and S. Liu, Journal of Nanoparticle
Research, 2015, 17, 189.
[2] X. Liu, J. Chen, P. Liu, H. Liu, G. Li, T. An and H, Zhao, Applied
Catalysis A: General, 2016, 521, 34-41.
[3] L. Z. Wu, B. Chen, Z. J. Li, C. H. Tung, Accounts of Chemical
Research, 2014, 47, 2177-2185.
[4] J. Jia, D. Li, J. Wan, and X. Yu, Journal of Industrial and
Engineering Chemistry, 2016, 33, 162-169.
[5] M. D. Regulacio and M.-Y. Han, Accounts of chemical research,
2016, 49, 511-519.
[6] S. Das, H. Sopha, M. Krbal, R. Zazpe, V. Podzemna, J. Prikryl and
J. M. Macak, ChemElectroChem, 2017, 4, 495-499.
[7] M. Kawa, A. Podborska and K. Szaciłowski, Journal of Physics:
Conference Series, 2016, 745, 032102.
[8] M. M. Momeni and Y. Ghayeb, Applied Physics A, 2016, 122,
620.
[9] W. Yin, W. Wang and S. Sun, Catalysis Communications, 2010,
11, 647-650.
Fig. 11. Schematic illustration of photo-induced charge transfer and separation at the
interface of TiO2-ZnO heterostructure.
[10] W.-T. Chen, A. Chan, D. Sun-Waterhouse, T. Moriga, H. Idriss
and G. I.N. Waterhouse, Journal of Catalysis, 2015, 326, 43-53.
[11] L. Qi, B. Cheng, J. Yu and W. Ho, Journal of Hazard Mater, 2016,
301, 522-530.
4. Conclusions
8 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 9 of 10
Journal of Materials Chemistry A
Please do not adjust margins
Journal Name
ARTICLE
[12] K. Tahir, A. Ahmad, B. Li, S. Nazir, A.U. Khan, T. Nasir, Z.U. Khan, [36] L. Pan, G. Shen, J. Zhang, X. Wei, L. Wang, J. ZouVaienwdArXti.clZehOannlinge,
DOI: 10.1039/C7TA10274G
R. Naz and M. Raza, Journal of Photochemistry and Photobiology B: Industrial & Engineering Chemistry Research, 2015, 54, 7226-7232.
Biology, 2016, 162, 189-198.
[37] S. Iijima, Nature, 1991, 354, 56.
[13] R. M. Kulkarni, R. S. Malladi, M. S. Hanagadakar, M. R. [38] M. Ge, C. Cao, J. Huang, S. Li, Z. Chen, K. Zhang, S. S. Al-Deyab
Doddamani, B. Santhakumari and S. D. Kulkarni, Journal of and Y. Lai, Journal of Material Chemistry A, 2016, 4, 6772-6801.
Materials Science: Materials in Electronics, 2016, 27, 13065-13074.
[14] P. S. Pillai, D. I. Prajapati, R. Ameta and Y. Ali, Scientific Reviews Wang, J. Z. Zhang and Y. Li, Nano Letters, 2011, 11, 3026-3033.
and Chemical Communications, 2016, 6, 12-18. [40] X. Zhang, J. Pan, A. J. Du, P. F. Lee, D. D. Sun and J. O. Leckie,
[39] G. Wang, H. Wang, Y. Ling, Y. Tang, X. Yang, R. C. Fitzmorris, C.
[15] S. Horikoshi, Y. Shirasaka, H. Uchida, N. Horikoshi and N. Chemistry Letters, 2008, 37, 424-425.
Serpone, Photochemical & Photobiological Sciences, 2016, 15, 1061- [41] R. Marchand, L. Brohan and M. Tournoux, Materials Research
1070.
[16] Y.-H. Lin, H.-T. Hsueh, C.-W. Chang and H. Chu, Applied [42] G. Wang, Q. Wang, W. Lu and J. Li, The Journal of Physical
Catalysis B: Environmental, 2016, 199, 1-10. Chemistry B, 2006, 110, 22029-22034.
[17] C. Xue, W. Wang, T. Han, Y. Wang, Y. Dong, S. Hu and J. Yang, [43] B. Liu, A. Khare and E. S. Aydil, ACS applied materials &
Chemistry Letters, 2016, 45, 1460-1462. interfaces, 2011, 3, 4444-4450.
[18] L. Wu, H. Zhao, L. Jin and H. Xu, Frontiers of Materials Science, [44] L. Shen, Z. Xing, J. Zou, Z. Li, X. Wu, Y. Zhang, Q. Zhu, S. Yang
2016, 10, 310-319. and W. Zhou, Scientific Reports, 2017, 7, 41978.
[19] S. Khanchandani, S. Kumar and A.K. Ganguli, ACS Sustainable [45] D.C. Hurum, A.G. Agrios and K.A. Gray, The Journal of Physical
Chemistry & Engineering, 2016, 4, 1487-1499. Chemistry B, 2003, 107, 4545-4549.
Bulletin, 1980, 15, 1129-1133.
[20] L. Wang, X. Duan, G. Wang, C. Liu, S. Luo, S. Zhang, Y. Zeng, Y. [46] W. Li, C. Liu, Y. Zhou, Y. Bai, X. Feng, Z. Yang, L. Lu, X. Lu and K.-
Xu, Y. Liu and X. Duan, Applied Catalysis B: Environmental, 2016, Y. Chan, The Journal of Physical Chemistry C, 2008, 112, 20539-
186, 88-96.
[21] C. Liu, L. Wang, Y. Tang, S. Luo, Y. Liu, S. Zhang, Y. Zeng and Y. [47] D. Yang, H. Liu, Z. Zheng, Y. Yuan, J C. Zhao, E. R. Waclawik, X.
Xu, Applied Catalysis B: Environmental, 2015, 164, 1-9. Ke and H. Zhu, Journal of the American Chemical Society, 2009, 131,
20545.
[22] L. Wang, X. Liu, J. Luo, X. Duan, J. Crittenden, S. Zhang, Y. Pei, Y. 17885-17893.
Zeng and X. Duan, Angewandte Chemie International Edition, 2017, [48] H.-H. Lo, N. O. Gopal, S. C. Sheu and S. C. Ke, The Journal of
56, 7610-7614.
Physical Chemistry C, 2014, 118, 2877-2884.
[23] X. B. Li, Y. J. Gao, Y. Wang, F. Zhan, X. Y. Zhang, Q. Y. Kong, N. J. [49] W. Zhou, L. Gai, P. Hu, J. Cui, X. Liu, D. Wang, G. Li, H. Jiang, D.
Zhao, Q. Guo, H. L. Wu, Z. J. Li, Y. Tao, J. P. Zhang, B. Chen, C. H. Liu, H. Liu and J. Wang, CrystEngComm, 2011, 13, 6643-6649.
Tung ang L. Z. Wu, Journal of the American Chemical Society, 2017, [50] T. Beuvier, M. Richard-Plouet and L. Brohan, The Journal of
139, 4789-4796.
[24] A. Muzakki, H. Shabrany and R. Saleh, AIP Conference [51] M. Ebrahimian, R. Soroush, A. Y. Salekdeh, M. Abazaril, A.
Proceedings, 2016, 1725, 020051. Langari, M. G. H. Kharaji. World Applied Sciences Journal, 2012, 19,
[25] V. Lachom, P. Poolcharuansin and P. Laokul, Materials Research 1602-1606.
Physical Chemistry C, 2009, 113, 13703-13706.
Express, 2017, 4, 035006.
[52] Q. Zhang, W. Fan and L. Gao, Applied Catalysis B:
[26] R. Vinoth, P. Karthik, K. Devan, B. Neppolian and M. Environmental, 2007, 76, 168-173.
Ashokkumar, Ultrason Sonochem, 2017, 35, 655-663.
[53] S. Chen, H. Zhang, X. Yu, W. Liu, J. Wang, Q. Liu and L. Chen,
[27] X. Guan, J. Shi, L. Guo, International Journal of Hydrogen Materials Chemistry and Physics, 2010, 124, 1057-1064.
Energy, 2013, 38, 11870-11877.
[54] E. Liu, L. Kang, F. Wu, T. Sun, X. Hu, Y. Yang, H. Liu and J. Fan,
[28] L. Roza, M.Y.A. Rahman, A.A. Umar and M.M. Salleh, Journal of Plasmonics, 2013, 9, 61-70.
Alloys and Compounds, 2015, 618, 153-158.
[29] J. Saffari, N. Mir, D. Ghanbari, K. Khandan-Barani, A.
Hassanabadi and M. R. Hosseini-Tabatabaei, Journal of Materials
Science: Materials in Electronics, 2015, 26, 9591-9599.
[30] L. Hou, L. Lian, L. Zhang, G. Pang, C. Yuan and X. Zhang,
Advanced Functional Materials, 2015, 25, 238-246.
[31] R. K. Sonker, S. R. Sabhajeet, S. Singh and B. C. Yadav, Materials
Letters, 2015, 152, 189-191.
[32] B. Siwach, S. Sharma and D. Mohan, Journal of Integrated
Science & Technology, 2017, 5, 1-4.
[33] S. Rehman, R. Ullah, A. M. Butt and N. D. Gohar, Journal of
hazardous materials, 2009, 170, 560-569.
[34] X. Yan, C. Zou, X. Gao, W. Gao, Journal of Materials Chemistry,
2012, 22, 5629-5640.
[35] Q. Hu, Y. Li, F. Huang, Z. Zhang, K. Ding, M. Wei and Z. Lin,
Scientific Reports, 2015, 5, 11499.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
Please do not adjust margins

Journal of Materials Chemistry A
Page 10 of 10
View Article Online
DOI: 10.1039/C7TA10274G
Table of contents entry
A novel ZnO NPs / mesoporous anatase−TiO2 (B) NWs heterojunction photocatalyst
was synthesized for environmental purification and hydrogen evolution.