Coral reef-like Pt/TiO2-ZrO2 porous composites for enhanced photocatalytic hydrogen production performance

Article abstract of DOI:10.1016/j.mcat.2019.110482

Polystyrene (PS) colloidal microspheres synthesized by the self-assembly technology were used as templates, a series of Pt/TiO₂-ZrO₂ composites with TiO₂ anatase phase and ZrO₂ tetragonal phase were synthesized by sol–gel, vacuum impregnation and photoreduction based on the colloidal crystal template. The composites treated with PS microspheres as templates exhibited an overall shape similar to the natural formation of uneven grooves. Meanwhile, there were three-dimensional ordered macroporous structures on the surface of composites, showing a coral reef-like porous structure. In addition, the loading of the precious metal Pt significantly enhanced the absorption of the composite in the visible region. The plasma resonance effect and the larger work function of Pt prolonged the carrier lifetime, thus enhancing photocatalytic properties of coral reef-like porous composite Pt/TiO₂-ZrO₂. The photocatalytic activity of coral reef-like porous composite Pt/TiO₂-ZrO₂ was higher in the experiment of multi-mode photocatalytic degradation of Rhodamine B, which had certain degradation of various dyes and organic pollutants. In the meanwhile, the experimental results of photocatalytic hydrogen production from water showed that the hydrogen production of coral reef-like Pt/TiO₂-ZrO₂ porous composites (7082.8 μmol g^?1) was more 600 times than that of TiO₂ (11.3 μmol g^?1) during 8 h, indicating that the loading of noble metal Pt, the synergistic effect of TiO₂ and ZrO₂, and the coral reef-like porous structure of the composite enhanced the photocatalytic activity.

Full text of DOI:10.1016/j.mcat.2019.110482

Molecular Catalysis 475 (2019) 110482
Contents lists available at ScienceDirect
Molecular Catalysis
journal homepage: www.elsevier.com/locate/mcat
Coral reef-like Pt/TiO -ZrO porous composites for enhanced photocatalytic
2
2
hydrogen production performance
Mingze An , Li Lia,b,⁎, Yanzhen Cao , Fengyan Ma , Dongxue Liu , Feng Gu
a,b
b
b
a
b
a
College of Materials Science and Engineering, Qiqihar University, Qiqihar, 161006, PR China
College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, 161006, PR China
b
A R T I C L E I N F O
A B S T R A C T
Keywords:
Polystyrene
Coral reef-like
Polystyrene (PS) colloidal microspheres synthesized by the self-assembly technology were used as templates, a
series of Pt/TiO -ZrO composites with TiO2 anatase phase and ZrO2 tetragonal phase were synthesized by
2
2
sol–gel, vacuum impregnation and photoreduction based on the colloidal crystal template. The composites
treated with PS microspheres as templates exhibited an overall shape similar to the natural formation of uneven
grooves. Meanwhile, there were three-dimensional ordered macroporous structures on the surface of composites,
showing a coral reef-like porous structure. In addition, the loading of the precious metal Pt significantly en-
hanced the absorption of the composite in the visible region. The plasma resonance effect and the larger work
function of Pt prolonged the carrier lifetime, thus enhancing photocatalytic properties of coral reef-like porous
Pt/TiO
2 2
-ZrO
Photocatalytic hydrogen evolution
2 2 2 2
composite Pt/TiO -ZrO . The photocatalytic activity of coral reef-like porous composite Pt/TiO -ZrO was
higher in the experiment of multi-mode photocatalytic degradation of Rhodamine B, which had certain de-
gradation of various dyes and organic pollutants. In the meanwhile, the experimental results of photocatalytic
2 2
hydrogen production from water showed that the hydrogen production of coral reef-like Pt/TiO -ZrO porous
−
1
−1
composites (7082.8 μmol g ) was more 600 times than that of TiO
2
(11.3 μmol g ) during 8 h, indicating that
the loading of noble metal Pt, the synergistic effect of TiO
2
and ZrO
2
, and the coral reef-like porous structure of
the composite enhanced the photocatalytic activity.
1
. Introduction
adjust the oxygen vacancy, two semiconductor modifications and co-
catalyst introduction and other aspects of research [9]. ZrO is a wide-
bandgap material with p-type semiconductor properties. The bandgap
value (E ) is between 3.25 and 5.0 eV. Therefore, some researchers use
the synergistic effect of two wide-bandgap semiconductors, TiO and
ZrO to change the band gap of the composite, thereby changing the
light absorption properties of the composite to enhance the photo-
catalytic activity of the composite. Sreethawong et al. [10] enhanced
the photocatalytic hydrogen evolution ability of noble metal Ag on
2
The ideal source of new energy should be cheap, abundant and
clean. Therefore, the use of solar energy in various ways has become a
research goal [1,2]. In recent years, so as to achieve the high photo-
catalytic activity of photocatalytic materials, solar energy has been
applied to the field of photocatalysis to develop semiconductors with
excellent electron separation and to combine with highly efficient co-
catalysts. Efforts to further improve the photocatalytic properties of
materials have been agreed upon by scientists [3,4].
g
2
2
TiO
photocatalytic degradation of organic pollutants by Cu-modified TiO
ZrO composites.
2 2
-ZrO by self-assembly technology. Rtimi et al. [11] enhanced the
In the study of hydrogen evolution from water by semiconductor
2
-
photocatalysis, TiO
2
photocatalyst is regarded as the excellent candi-
2
date material because of its low cost, non-toxicity, chemical stability
and suitable energy band value for hydrogen production [5]. However,
the ability of TiO photocatalyst to capturing light in the visible region
2
is weak, of which the separation ability of photogenerated carriers is
low [6,7]. To some extent, the enhancement of photocatalytic hydrogen
evolution ability is restrained, and the practical application value is
limited [8]. In order to solve these problems, researchers began to try to
Furthermore, there are many research results on the enhancement
of photocatalytic properties of materials by designing and obtaining
different types of materials with various morphologies. Imhof et al. [12]
prepared composites with macroporous structure by using emulsion
droplets as the template. The composites not only had large specific
surface area, high porosity, but also showed the characteristics of strong
periodicity of pore structure and uniform pore size. Our research team
⁎
Corresponding author at: College of Materials Science and Engineering, Qiqihar University, Qiqihar, 161006, PR China.
E-mail addresses: qqhrll@163.com, qqhrlili@126.com (L. Li).
https://doi.org/10.1016/j.mcat.2019.110482
Received 24 March 2019; Received in revised form 4 June 2019; Accepted 18 June 2019
2468-8231/ © 2019 Elsevier B.V. All rights reserved.

M. An, et al.
Molecular Catalysis 475 (2019) 110482
had synthesized a kind of gully morphology by self-assembly tech-
nology, and the preparation process is simple and the morphology is
Finally, the uniformly mixed TiO
cuum oven for 12 h under vacuum impregnation. The dry powder TiO
ZrO was calcined at 600 ℃ for 7 h, then was labeled as TiO -ZrO (C).
1.0 g TiO -ZrO (C) composite was uniformly dispersed into 50 mL of
deionized water and placed in a photoreduction reactor, then sodium
sulfide (3.0 g) was added as a sacrificial agent, and then the prepared
0.5 mL platinum standard solution was added. The mixture was uni-
formly mixed and then evacuated. Under the irradiation of 300 W
xenon lamp for two hours, the photoreduction loading of Pt was carried
out. Finally, the nanocomposites were washed with deionized water
and ethanol for four times and dried in vacuum. The nanocomposites
2 2
-ZrO precursor was placed in a va-
2
-
easy to control [13]. In addition, Ren et al [14] synthesized Pt/TiO
2
2
2
2
irregular pore materials using lotus pollen as a template agent. Because
of large specific surface area and good electron trap effect of precious
metal Pt, the composites had good hydrogen production properties.
The studies on the modification of semiconductors with precious
metals as electronic traps are to improve the photocatalytic activity and
hydrogen evolution of composites by changing the properties of com-
posites. Among them, reports about Pt are more common. The hy-
2
2
drogen production of Pt/TiO
0.0 mmol after 5 h irradiation. Therefore, if Pt can be doped into
semiconductor TiO and ZrO composites, it can be used as a co-catalyst
to enhance the photocatalytic performance of semiconductor materials
16–18].
According to as-results, a kind of coral reef-like porous composite
2
prepared by Lin et al. [15] was
6
2 2 2 2
were labeled as Pt/TiO -ZrO (C). The TiO and ZrO used for com-
parison were synthesized by a sol–gel method in combination with
calcination.
2
2
[
In addition, the contents of Pt, TiO
samples were determined by ICP-AES. The results show that the weight
percentages of Pt, TiO and ZrO in coral reef Pt/TiO -ZrO (C) porous
2 2 2 2
and ZrO in Pt/TiO -ZrO (C)
was prepared by sol–gel and vacuum impregnation combined with
photoreduction method using polystyrene (PS) colloidal microspheres
synthesized by self-assembly technology as the template in this paper.
On the one hand, by depositing precious metal Pt as an electron trap,
the recombination of photogenerated electron–hole pairs in semi-
2
2
2
2
composites are 1.2%, 16.8% and 50.1%, respectively.
2.3. Characterization
conductor TiO
2
and ZrO
2
is restrained, and the photogenerated elec-
X-ray diffraction (XRD) patterns of the samples were analyzed using
an X-ray diffractometer from 20° to 80° with Kα radiation
(λ = 0.15406 nm) from Bruker-AXS (D8), Germany. The XPS spectrum
of the sample was determined by using an ESCALAB250Xi X ray pho-
toelectron spectrometer purchased from Thermo Company, USA, where
trons are effectively captured, thus facilitating the separation of pho-
togenerated electron–hole pairs. At the same time, photogenerated
electrons trapped by Pt can well participate in the photodissociation of
water to produce hydrogen. For another, the coral reef-like porous
structure has some advantages: firstly, the material has a groove
structure and a porous structure, which is very favorable to capture
photons. In addition, a comparison of the planar structure, the porous
structure on the groove is advantageous to prolong the electron transfer
path. Secondly, a large number of small particles are accumulated on
the surface of the catalyst, which has a good diffuse reflection effect on
the light, which can improve the utilization ratio of the catalyst to light
and thus improve the photocatalytic activity. Meanwhile, the synthe-
−8
the residual gas pressure of the Mg K-ADES source was less than 10
Pa. The PL photoluminescence spectra of the samples were measured by
the F-7000 fluorescence spectrophotometer of Hitachi, Japan. SEM
analysis of the sample was carried out using the scanning electron
microscope (SEM) of 5 kV, model S-4700, purchased from Hitachi,
Japan, and the determination temperature was 77 K and the model was
3H-2000PS2, purchased from Bethesdale instrument Technology
(Beijing) Co., Ltd. The HR-TEM photos of the sample were obtained by
the Japanese electronic JEM-2100 F model. The accelerated voltage is
200 kV. The electrochemical impedance was measured using a PEC-
1000 photoelectrochemical test system manufactured by Perfectlight
Co., Ltd. The ICP-AES was carried on an Agilent Technologies 7500ce
inductively coupled plasma atomic emission spectrum. The TU-1901
dual-beam UV–vis diffuse reflectance absorption spectra produced by
Beijing General Analysis Company were used as a reference, and the
2 2
sized coral reef-like Pt/TiO -ZrO porous material has the advantages of
simple preparation conditions, high reproducibility, high yield, large
specific surface area, excellent photocatalytic degradation of organic
pollutants and excellent photolysis activity.
2. Experimental
2.1. Materials
4
BaSO solid was used as a reference. The absorbance of the sample
solution was determined by the TU-1901 UV–vis dual beam spectro-
Titanium (IV) isopropoxide (C12
H
28
O
4
Ti, 98%) was purchased from
photometer produced by Beijing General Analysis Company.
Shanghai Darui Fine Chemical Co., Ltd.; Zirconium (IV) butoxide so-
lution (C16 Zr, 80 wt%) was purchased from Shanghai Meryer
Chemical Technology Co., Ltd.; Chloroplatinic acid hexahydrate
PtCl ·6H O, 38.7%) was purchased from Shanghai Meryer Chemical
Technology Co., Ltd.; Polyethylene-polypropylene glycol (C
P123) was purchased from Saan Chemical Technology (Shanghai) Co.,
Ltd.; Styrene (C , 99%) was purchased from Shanghai Meryer
Chemical Technology Co., Ltd.; Degussa P25 and K were pur-
chased from Tianjin Tianda Purification Materials Fine Chemical Plant.;
Methyl orange (MO), Congo red (CR), methylene blue (MB),
Rhodamine B (RhB) and salicylic acid (SA) are commercially available
analytical reagents and not further purified. All experimental water is
deionized water.
H
36
O
4
2.4. Photocatalytic experiments
(
H
2
6
2
The photocatalytic experimental reaction devices of different modes
are self-made. The ultraviolet light source is 125 W high pressure
mercury lamp (the main emission wavelength is 313.2 nm), visible light
source is 400 W xenon lamp (the main emission wavelength is more
than 410 nm, the inner casing is made of special glass to filter the ul-
traviolet light emitted by Xe lamp), and the solar light is simulated. The
source is 1000 W xenon lamp (external type, Shanghai Baoxin instru-
ment Co., Ltd., emission spectrum is close to full spectrum). The mi-
crowave-assisted photocatalytic experiment uses H type microwave
electrodeless lamp (main emission wavelength 280 nm) as the light
source.
5 10 2
H O ,
8 8
H
2 2 8
S O
2
.2. Preparation of Pt/TiO
2
-ZrO
2
nanocomposites
In the ultraviolet, visible, simulated sunlight and microwave-as-
sisted photocatalytic experiments, 0.15g, 0.3g, 0.15g, and 0.5g of cata-
lyst were dispersed in a newly configured solution (concentration:
50 mg/L) in a volume of 90 mL, 220 mL, 100 mL, and 500 mL, respec-
tively. The suspension was sonicated for 10 min, stirred in the dark for
30 min, and placed in a photocatalytic reactor for photocatalytic ex-
periments. Samples were taken at regular intervals during the reaction
and their absorbance values were measured at λmax by a TU-1901
Polystyrene microspheres template was synthesized by emulsion
free polymerization [19]. Polystyrene (PS) microspheres suspension
was centrifuged for 90 min. The lower emulsion of 8 mL was extracted
in a beaker and 1 mL of tetraisopropyl titanium (TTIP) and 2 mL of n-
butoxy zirconium (C16
The TiO -ZrO precursor was obtained by stirring for two hours.
36 4
H O Zr) were added and hydrolyzed in time.
2
2
2

M. An, et al.
Molecular Catalysis 475 (2019) 110482
Fig. 1. SEM images of polystyrene microspheres (a–d) and Pt/TiO
2
-ZrO
2
(C) composites (e, f) (Inset : g is a sectional view of Pt/TiO
2
-ZrO
2
(C) composite; h is a natural
coral reef structure image).
UV–vis dual beam spectrophotometer.
channel, and can well introduce the light and molecules into the in-
ternal space of Pt/TiO -ZrO (C). At the same time, in Fig. 1e, it can be
2
2
seen that the composites have uneven ravines and porous structure,
indicating that the synthesized composite material has certain perme-
ability and a reflection and diffraction effect on light under the action of
light.
3
. Results and discussion
3.1. SEM analysis
This unique coral reef-like porous structure has good permeability
and is conducive to the photon reflection path in the structure, in-
creasing the effective optical path length caused by photon multiple
reflection in the structure. Meanwhile, this unique coral reef-like
porous structure contributes to capture more efficient photon, thereby
improving light trapping efficiency.
With a view to study the surface morphology of Pt/TiO
2
2
-ZrO (C)
sample, polystyrene microspheres and Pt/TiO -ZrO (C) were analyzed
2
2
by scanning electron microscopy (SEM), and the results are shown in
Fig. 1. As can be seen from Fig. 1(a–d), the synthesized polystyrene
microspheres exhibite a monodisperse and closely packed structure,
and its average diameter is about 320 nm. From Fig. 1e, Pt/TiO
2
-
For the purpose of revealing the role of PS microspheres as tem-
plates in the formation of porous structure materials, the possible for-
ZrO (C) has a coral reef-like structure, which is mainly composed of the
2
accumulation of nanoparticles, and the pore structure and a small
amount of nanoparticles can be clearly seen on the surface. The porous
structure is formed by calcination of PS microspheres template, while a
small amount of particles on the surface are photoreductively deposited
Pt nanoparticles, which are very similar to the naturally formed coral
reef-like morphology (the naturally formed coral structure is shown in
Fig. 1h).
Most noteworthy, the coral reef surface morphology in Fig. 1(e–f)
exhibits relatively uniform, good groove network structure and long-
range periodic macropores with a pore size of 80–120 nm. It is also
interesting to see that the gully morphology is parallel to each other and
perpendicular to the outer surface of the particle. From Fig. 1f (in the
illustration Fig. 1g), it is clear to see that the ravines arranged in par-
allel rows completely cross the whole material and extend; this special
morphology can increase the optical transmission pathway as a
mation mechanism of coral reef-like Pt/TiO
is inferred (Fig. 2).
2 2
-ZrO (C) porous structure
During the synthesis process, after PS colloidal microspheres are
centrifuged for a period of time, the PS colloidal microspheres self-as-
semble from the original monodisperse loose state into a denser ar-
rangement state. Of course, PS colloidal microspheres not fully as-
sembled also existe in the centrifugation process (Fig. 2a). The PS
colloidal microspheres after centrifugation can fully absorb water.
When the droplets of tetraisopropoxy titanium and n-butoxy zirconium
contact with PS colloidal template, a thin and dense semi-permeable
film is formed at the droplet interface, then hydrolyzes to produce part
2 2 2 2
of TiO and ZrO particles (Fig. 2b). The TiO and ZrO nanoparticles
are then filled into the PS colloidal microspheres template under stir-
ring (Fig. 2c). Due to the friction and the adsorption between the PS
3

M. An, et al.
Molecular Catalysis 475 (2019) 110482
2 2
Fig. 2. Schematic illustration of the formation process of coral reef-like Pt/TiO -ZrO porous composites.
microspheres and the TiO
2
and ZrO
2
particles, a tightly packed cover
2
(JCPDS 21–1272) [20,21]. The tetragonal phase of ZrO is observed at
layer can be formed under vacuum impregnation (Fig. 2d). As a result,
the appearance of coral reefs has gradually formed, and the height and
the depth of coral reefs also changes, showing the three-dimensional
characteristics of coral reefs. During the formation process, the colloidal
activity and hydrophilic properties of PS colloidal microspheres can
accelerate the formation of coral reefs. The expansion of the PS col-
loidal microspheres and the increase of the adsorption force can obtain
a coral reef composite with a large active surface. In addition, the PS
colloidal template in the solution is adsorbed on the surface of the
particles by vacuum impregnation to form a two-layer structure
2θ = 28.3°, 30.3°, 31.4°, 35.3°, 50.4° and 60.0°, corresponding to (111),
(102), (201), (211), (302) and (402) crystal plane (JCPDS 65–1024)
[22]. The characteristic peaks of (Ti-Zr)O
posite Pt/TiO -ZrO (C), owing to the formation of (Ti-Zr)O
during the calcination process, while the Pt characteristic peaks do not
appear in the composite Pt/TiO -ZrO (C), which may be due to the low
loading of Pt [23]. Compared with ZrO , the diffraction peaks corre-
sponding to (102) planes of Pt/TiO -ZrO (C) and TiO -ZrO (C) are
2
also appeares in the com-
2
2
2
oxide
2
2
2
2
2
2
2
weakened, while the diffraction peaks corresponding to (111) and
(201) planes are strengthened. The reason for the difference is that the
(
Fig. 2e), and finally, by the calcination to remove the PS template, a
peak strength of (111) and (201) faces of TiO
enhanced by further compounding between ZrO
2
-ZrO
2
(C) composites is
and TiO nano-
"coral reef-like" porous structure is obtained (Fig. 2f).
2
2
particles during the calcination process, and the peak strength of (111)
and (201) faces increases after loading the noble metal Pt. However, the
intensity of the characteristic peaks does not decrease but continued to
increase after loading precious metal Pt, indicating that the intensity of
characteristic peaks could be increased to a certain extent by photo-
chemical reduction loading of precious metal Pt. At the same time, the
3
.2. XRD analysis
2 2 2 2
The crystallinity and phase composition of ZrO , TiO , TiO -ZrO (C)
and coral reef-like Pt/TiO
method. The results are shown in Fig. 3. As shown in Fig. 3, the Pt/
TiO -ZrO (C) presents strong diffraction peaks at 2θ = 25.4°, 37.8°,
8.2°, 53.9°, 55.2°, 62.8°, and 75.2°, corresponding to (110), (200),
212), (310), (301), (312) and (104) crystal surface of TiO anatase
2 2
-ZrO (C) samples were characterized by XRD
2
θ = 30.3° is the (102) surface of the ZrO
Pt/TiO -ZrO (C) corresponds to the (111) surface at 2θ = 28.3°. The
main characteristic peak position of the composite is offset, which is
due to the inhibition of the growth of (102) crystal surface by TiO and
2
, and the composite material
2
2
2
2
4
(
2
2
Pt nanoparticles. Meanwhile, the strength of the characteristic peaks on
the (110) plane of the corresponding titanium dioxide continues to
increase, indicating that the crystal form of titanium dioxide in the
2 2
composite Pt/TiO -ZrO (C) is more perfect.
The grain size of the sample is calculated according to the Scherrer
formula, and the results are shown in Table 1. By comparing the data of
each group of samples in Table 1, it is found that the crystal size of the
Table 1
Grain size (D*), band gap energy (Eg), and cell parameters of different mate-
rials.
Sample
D* (nm) Eg (eV) Crystal parameters
TiO
Crystal parameters
(
2
)
(ZrO
2
)
a(Å)
c(Å)
a(Å)
c(Å)
Pt/TiO
2
-ZrO
2
(C) 24.2
26.5
2.89
2.99
3.15
3.85
3.708
3.873
3.875
3.986
9.695
9.794
9.785
9.865
3.895
3.795
3.615
3.754
5.265
5.223
5.154
5.132
TiO
TiO
2
-ZrO (C)
2
2
25.8
26.4
2 2 2 2 2
Fig. 3. X-ray diffraction patterns of TiO , ZrO , TiO -ZrO (C) and Pt/TiO -
ZrO (C).
2
ZrO
2
4

M. An, et al.
Molecular Catalysis 475 (2019) 110482
2 2
Fig. 4. X-ray photoelectron spectroscopy of Pt/TiO -ZrO (C): (a) full-spectrum; (b) O1s; (c) Ti2p; (d) Zr3d; (e) Pt4f.
noble metal Pt supported composite TiO
unit cell parameters of TiO decrease, and the cell parameters of ZrO
increase. It is found from the data in Table 1 that the large grain size of
the synthesized TiO -ZrO (C) composites with Pt doping inhibits the
formation of TiO -ZrO (C) grains [24]. This belongs to PtO or Pt na-
noparticles with good dispersion can be uniformly loaded on TiO
ZrO (C), thus inhibiting the growth of Pt/TiO -ZrO (C) crystal, re-
sulting in the reduction of grain size [25–31].
2
-ZrO
2
(C) becomes smaller, the
Fig. 4(c), the binding energies of Ti at 459.0 eV and 465.2 eV corre-
spond to Ti2p3/2 and Ti2p1/2, respectively, indicating that Ti in the
2
2
4+
composite exists in the form of Ti [34]. The electron binding energies
of Zr3d orbits are 181.9 eV and 184.8 eV, respectively, corresponding to
the characteristic peaks of Zr3d5/2 and Zr3d3/2 in Fig. 4(d), indicating
2
2
2
2
4+
2
-
that Zr in the composite mainly exists in the form of Zr [35]. Fig. 4(e)
is the Pt4f peak of Pt/TiO -ZrO (C). From Fig. 4(e), it can be clearly
found that Pt/TiO -ZrO (C) has four peaks at 71.7, 73.2, 75.1 and 76.1
2
2
2
2
2
2
2
of Pt 4f. The characteristic peaks at 71.7 and 76.1 eV correspond to the
metal PtO states of Pt4f7/2 and Pt4f5/2, respectively, while the char-
3.3. XPS analysis
acteristic peaks at 73.2 and 75.1 eV correspond to Pt4f5/2 and Pt4f7/2
,
0
The element composition and valence state in Pt/TiO
2
-ZrO
2
(C)
respectively, belonging to elemental Pt . Therefore, the coexistence of
0
composites are analyzed by XPS analysis, as shown in Fig. 4. It can be
observed from the full spectrum of Fig. 4(a) that Ti, O, Zr, C, and Pt are
platinum oxide (PtO) and Pt elemental (Pt ) in the coral reef-like Pt/
2 2
TiO -ZrO (C) porous composite was confirmed [36,37]. Among them,
mainly present in the Pt/TiO
2
-ZrO
2
composite. The characteristic peaks
the PtO in the composite can provide more active sites, and their active
sites will promote photocatalytic hydrogen evolution [38,39].
of carbon appeared in the whole spectrum, which can be attributed to
the fact that the calcination process of polystyrene microspheres may
not be burned out, or the characteristic peaks of C appeared in the
instrument itself and the absorption of carbon dioxide in the air [32].
3.4. UV–vis diffuse reflectance spectra
Fig. 4(b) is a characteristic peak of O1s. In the Pt/TiO
composite, oxygen is mainly present in the form of lattice oxygen and
adsorbed oxygen, and the valence state of oxygen is −2 [33]. In
2
-ZrO
2
porous
Due to research the light absorption properties of TiO
ZrO (C) and Pt/TiO -ZrO (C) composites, UV–vis/DRS absorption
spectra were analyzed, as shown in Fig. 5a. It can be seen from Fig. 5a
2 2 2
, ZrO , TiO -
2
2
2
5

M. An, et al.
Molecular Catalysis 475 (2019) 110482
Fig. 5. UV–vis/DRS spectra of Pt/TiO
2
-ZrO
2
(C), TiO
2
-ZrO
2
(C), TiO
2
and ZrO
2
(a) and Kubelka–Munk energy curve map (b). (For interpretation of the references to
colour in this figure text, the reader is referred to the web version of this article.)
that TiO
absorption edge is located at 380 nm. The absorption of ultraviolet light
by ZrO at 350 nm has dropped sharply, indicating that the absorption
edge of ZrO to ultraviolet light is lower than 350 nm. After the com-
bination of titanium dioxide and zirconium dioxide, the prepared TiO
ZrO
phenomenon [40]. However, the absorption intensity of Pt/TiO
ZrO
toreduction of noble metal Pt is obviously improved in the ultraviolet
and visible regions, and a certain red shift occurs. This red shift can be
attributed to the presence of surface effects, and the formation of coral
reef-like porous structures increases surface tension, causing lattice
distortion [41]. At the same time, to realize the merit of template in the
synthesis method and morphology induced reactivity in photocatalysis,
the composites are obtained via template free method, the optical ab-
2
shows the absorption in the ultraviolet region and its light
active sites for photocatalytic reactions. It can be clearly seen from
Fig. 6b that the Pt/TiO -ZrO porous composite material is similar to
the naturally formed gully, and the surface has a large number of pore
structures. This further demonstrates the coral reef-like porous struc-
2
2
2
2
2
-
-
ture of Pt/TiO
lysis). With the intention of further prove the crystal phase structure of
Pt/TiO -ZrO composites. Fig. 6c, d is the selected area electron dif-
fraction pattern of zirconium dioxide and titanium dioxide in Pt/TiO
ZrO composites and different crystal faces of platinum by Fourier
transform processing using Digital Micrograph software. At the same
time, from Fig. 6c, d, it can be observed that Pt, TiO and ZrO lattice
streaks appear in different selected regions of Pt/TiO -ZrO composites,
indicating that the coral reef-like Pt/TiO -ZrO composites are suc-
cessfully synthesized. Fig. 6e–g gave more specific information about
different crystals, where the lattice spacing of ZrO is d = 0.244 nm,
which belongs to the (111) crystal plane of ZrO [47], and the inter-
planar spacing d = 0.340 nm corresponds to the (110) crystal plane of
TiO [48]. The interplanar spacing d = 0.223 nm corresponds to the
(111) crystal plane of Pt [49]. The lattice spacing of the clear crystals
2 2
-ZrO composites (this is consistent with the SEM ana-
2
(C) composite has a certain visible light response and a red shift
2
2
2
2
(C) composites of coral reef-like porous structure formed by pho-
2
-
2
2
2
2
2
2
2
2
sorption properties of the UV–vis diffuse reflection of Pt/TiO
TiO and Pt/ZrO and Kubelka-Munk energy curve map are shown in
support information Fig. S1(a, b). In addition, the composite Pt/TiO
ZrO (C) has a strong absorption in the range of 425–580 nm, which can
2
-ZrO
2
, Pt/
2
2
2
2
-
2
2
be attributed to the plasmon resonance effect (SPR effect) of Pt [42,43].
The above results indicate that the loading of noble metal Pt is bene-
ficial to the response of the composite in the visible region and en-
hances the absorption of visible light [44].
indicates the presence of Pt, TiO
sites and better crystallinity.
2 2
and ZrO in the synthesized compo-
2
3.6. N adsorption–desorption analysis
According to the Kubelka–Munk energy curve chart (Fig. 5b), the
forbidden band widths of TiO
ZrO
Table 1. It can be seen from the values obtained in Table 1 that the E
value of Pt/TiO -ZrO
with the TiO , ZrO and TiO
fact that Pt/TiO -ZrO (C) with coral reef-like porous structure has a
strong absorption of visible light and the absorption of light extends to
visible region. The results indicate that the coral reef-like porous
2 2
structure Pt/TiO -ZrO (C) will have higher photocatalytic activity
2
, ZrO
2
, TiO
2
-ZrO
2
(C) and Pt/TiO
2
-
In the interest of studying the surface physicochemical properties of
Pt/TiO -ZrO , Pt/TiO -ZrO (C), TiO -ZrO (C), TiO and ZrO samples,
the results of N adsorption–desorption test are shown in the support
information Fig S3 and Fig. 7. According to the definition of IUPAC, the
above isotherms of Pt/TiO -ZrO (C), TiO -ZrO (C), TiO and ZrO be-
long to the type IV isotherm and have the H3 type hysteresis loop. The
type of this isotherm and its hysteresis loop is caused by capillary
condensation and special coral reef-like porous structure [50]. From the
pore size distribution curve of Fig. 7 (shown in the inset), the pore size
2
(C) were obtained by the tangent method. The results are shown in
2
2
2
2
2
2
2
2
g
2
2
2
(C) composite is significantly reduced compared
-ZrO (C) composite, which is due to the
2
2
2
2
2
2
2
2
2
2
2
2
[
45,46].
distribution of Pt/TiO
be observed in the inset of Fig. 7(a) that the mesopores at ① and ② are
2.35 nm and 27.07 nm, respectively, due to the accumulation of TiO
and ZrO nanoparticles and the formation of gullies, which are re-
2 2
-ZrO (C) has certain broadness. From this it can
3.5. TEM and HR-TEM analysis
2
2
In order to further study the composition and structure of the
spectively microporous and mesoporous structures. The pore size of ③
sites is about 85 nm, which is due to the macroporous structure on the
coral reef surface after vacuum impregnation, timely calcination and
photoreduction (Fig. 8a). Therefore, there is a porous structure on the
composites, the TEM and HR-TEM analysis of the coral reef-like Pt/
TiO -ZrO porous structural materials were carried out. The results are
shown in Fig. 6. Fig. 6a can be seen that the Pt/TiO -ZrO composite
2
2
2
2
formed by vacuum filling, calcination and photoreduction treatment
2 2
surface of the Pt/TiO -ZrO (C) composite. Because of the existence of
with PS microspheres as a template has a coral reef-like porous struc-
this structure, the composite has more photocatalytic active sites,
thereby enhancing the photocatalytic activity of the composite [51,52].
In the meanwhile, the porous structure can serve as a mass transfer
channel for the substance, which is beneficial to the photocatalytic
activity of the photogenerated electrons [53].
ture. Among them, the bright portion is a porous structure of Pt/TiO
ZrO
2
-
2
.
Because of this special porous and surface gully, it provides favor-
able channel for photogenerated electrons, which reduces the mass
transfer resistance of the material to some extent and enhances the
In addition, from this it can be the data in Table 2, the specific
carrier lifetime of Pt/TiO
2
-ZrO
2
porous composites, providing more
2 2 2
surface area of Pt/TiO -ZrO (C) is higher than that of monomers TiO
6

M. An, et al.
Molecular Catalysis 475 (2019) 110482
2 2
Fig. 6. HR-TEM images of (a–d) and FFT line plots (e–g) of Pt/TiO -ZrO (C).
and ZrO
2
, and TiO
2
-ZrO
2
(C). This is mainly caused by the photo-
In general, we think that the special structure of the coral reef-like
Pt/TiO -ZrO (C) porous composite can promote the separation of
electron–hole pairs, and the separated electrons and holes can
reduction of the noble metal Pt, which makes the surface area of the
composite rough, resulting in the increase of the specific surface area.
2
2
7

M. An, et al.
Molecular Catalysis 475 (2019) 110482
Fig. 7. N
2
adsorption–desorption isotherms of Pt/TiO
2
-ZrO
2
(C) (a), TiO
2
-ZrO
2
(C) (b), ZrO
2
(a), and TiO
2
(d) (insets show the BJH pore size distribution curves).
Among them, TiO
indicating that the combination of photogenerated electrons and holes
is faster. The emission intensity of composite TiO -ZrO (C) in the region
decreases, indicating that the recombination rate of excited electron–-
hole pairs caused by electron transfer after ZrO and TiO recombina-
tion is slower; among them, after loading Pt nanoparticles on the sur-
face of TiO -ZrO (C), the intensity of the peak is further reduced, which
2 2
and ZrO have the strongest emission in the region,
2
2
2
2
2
2
indicates that the loaded Pt nanoparticles have accelerated electron
migration, so reducing electron–hole pairs recombination and
prolonging photocarrier carrier lifetime. Therefore, the loaded Pt na-
noparticles can correspondingly improve the photocatalytic perfor-
mance of Pt/TiO
2 2
-ZrO (C).
3.8. Photocatalytic activity
Fig. 8. Photoluminescence spectra (excitation: 320 nm) of different samples.
For the sake of studying the photocatalytic properties of composite
Pt/TiO -ZrO (C), the photocatalytic degradation experiments were
carried out in UV, visible, simulated sunlight and microwave-assisted
modes. The experimental results are shown in Fig. 9. It can be seen from
Table 2
2
2
Specific surface area, average pore size, and pore volume of Pt/TiO
TiO -ZrO (C), TiO and ZrO
2 2
-ZrO (C),
2
2
2
2
.
Sample
S
BET (m2 g−1
)
D (nm)
Vtotal (cm3 g−1
)
Fig. 9(a) that the degradation of Pt/TiO
than that of direct photolysis, P25, TiO
TiO -ZrO (C) under ultraviolet light irradiation. The results show that
the synergistic effect of TiO and ZrO combined with the loading of
noble metal Pt and the synthesis of coral reef porous structure can ef-
fectively improve the photocatalytic activity of Pt/TiO -ZrO (C) com-
2
-ZrO
2
(C) composites is higher
2
, ZrO
2
, Pt/TiO , Pt/ZrO and
2
2
Pt/TiO
2
-ZrO
2
(C)
14.2
12.5
12.2
11.0
27.5
15.6
12.8
13.0
0.101
0.071
0.054
0.036
2
2
TiO
TiO
2
-ZrO (C)
2
2
2
2
ZrO
2
2
2
posites. The kinetic curves of rhodamine B degraded by different cat-
alysts under ultraviolet light irradiation, as shown in Fig. 9(b). It can be
seen from Fig. 9(b) that lnC /C has a linear relationship with the re-
successfully migrate to the surface and then transfer to the surface to
react to organic pollutants degraded to CO and water. The porous and
gully structures on the surface of the coral reef-like Pt/TiO -ZrO (C)
composites increase the charge transfer and inhibit the electron–hole
recombination to improve the photocatalytic activity of the material.
2
0
t
2
2
action time t, which indicates that follows the quasi-first-order reaction
kinetics. The rate constants of direct photolysis, P25, TiO , ZrO , Pt/
2
2
TiO , Pt/ZrO2 and TiO -ZrO (C) and Pt/TiO -ZrO (C) by UV photo-
2
2
2
2
2
catalytic degradation of rhodamine
B
were calculated as:
−
1
1
−1
−1
−1
3.7. PL analysis
0.0016 min
,
0.0056 min
,
0.007 min
,
0.0068 min
,
−
−1
−1
−1
0.0062 min , 0.0135 min , 0.0194 min , 0.0249 min , respec-
The photo-luminescence spectra were investigated to examine the
tively. Fig. 9(c–e) shows photocatalytic degradation of rhodamine B
charge separation efficiency in different samples. As shown in Fig. 8,
the PL spectra of all samples are included in the range of 200–800 nm.
under visible light, simulated sunlight and microwave-assisted irra-
diation. It can be seen that Pt/TiO -ZrO (C) has relatively high
2 2
8

M. An, et al.
Molecular Catalysis 475 (2019) 110482
Fig. 9. Degradation of Rhodamine B by different catalysts irradiated by ultraviolet light (a), kinetic results of degradation of Rhodamine B with different catalysts
under UV irradiation (b), visible light irradiation (t = 210 min) (c), simulated sunlight irradiation(t = 300 min) (d), photocatalytic degradation of Rhodamine B
under microwave-assisted irradiation(t = 120 min) (e), photocatalytic degradation profiles of Pt/TiO -ZrO (C) for different dyes and organic solutions under UV
2 2
irradiation (f).
photocatalytic activity under the above experimental conditions, which
is mainly due to the unique coral reef-like porous structure of the
that the catalyst has certain practical application value. Fig. 9(f) is the
result diagram of Pt/TiO -ZrO (C) UV-photodegradation of different
2
2
synthesized Pt/TiO
In addition, it should be emphasized that the high activity of Pt/
TiO -ZrO (C) microwave assisted photocatalysis is also related to its
2
-ZrO
2
(C) composite.
dyes. It has the best degradation effect on Rhodamine B, but also has
different degrees of degradation on other dyes, indicating that the
composite has certain universality.
2
2
special morphology and microwave radiation. Microwave-assisted
photocatalysis is to produce ultraviolet radiation by microwave elec-
trodeless lamp, directly destroy the structure of organic pollutants by
bond breakage. At the same time, microwave can produce additional
defect sites on the catalyst. The polarizing effect of high defect catalyst
can improve the possibility of photoelectron transfer. The surface defect
of porous can become the trapping center of photogenerated electron
and hole and restrain their recombination. Thus, the photocatalytic
activity of the catalyst is further enhanced.
In order to investigate the practical application of the catalyst, the
photoabsorption of the catalyst in UV region was evaluated under si-
mulated sunlight condition, but the proportion of ultraviolet light in
simulated solar light is very small. Under these conditions, the catalyst
still degrades the model molecule to a certain extent, which indicates
3
.9. Photocatalytic hydrogen evolution
It can be seen from Fig. 10(a) that under the same experimental
conditions, coral reef porous structure composite Pt/TiO
better hydrogen evolution ability in photolysis of water than that of
TiO and ZrO . After 8 h reaction with methanol as the sacrificial agent,
the total hydrogen production of was 7064.3 μmol g , which was
obviously higher than that of TiO -ZrO (C), TiO and ZrO , and was
more 600 times than that of TiO . The high hydrogen production of Pt/
TiO -ZrO (C) can be attributed to the following: (1) Pt/TiO -ZrO (C)
has unique coral reef porous structure and high efficiency lighting
ability, which can effectively capture the irradiated light energy. (2)
2 2 2
The composite of TiO and ZrO is a factor. By combining TiO with
2 2
-ZrO (C) has
2
2
−
1
2
2
2
2
2
2
2
2
2
9

M. An, et al.
Molecular Catalysis 475 (2019) 110482
Fig. 10. Result diagram of hydrogen production from different catalysts (8 h) (a); cycle diagram of Pt/TiO
2
-ZrO
2
(C) photolysis water to hydrogen production (b).
2
strong light stability and ZrO with redox property, the obtained
composite will have the advantages of both. Moreover, the different
energy levels between the two semiconductors can improve the se-
paration of photogenerated charges and facilitate the transfer of pho-
togenerated carriers from ZrO
2 2
to TiO . (3) The photoabsorption
property of the catalyst is enhanced by doping precious metal Pt. The
SPR effect of Pt increases the transport pathway of photogenerated
carriers and reduces the photoelectron–hole pair recombination. Pt acts
as the active site of surface reaction, which further improves the ac-
tivity of hydrophotolysis to produce hydrogen. In addition, a small
2 2
amount of PtO present in the coral reef-like Pt/TiO -ZrO (C) porous
composite can promote the production of hydrogen by photolysis. The
beneficial effects of PtO in promoting activity (hydrogen evolution) are
as follows: (1) PtO can capture electrons as a cocatalyst during photo-
catalytic hydrogen evolution, promote separation of photogenerated
charges, and prolong photogenerated carriers and improve the photo-
catalytic hydrogen evolution performance of composite materials. (2)
PtO nanoparticles act as active sites to improve charge separation and
migration at the interface between the promoter and the semi-
conductor. At the same time, the interaction between Pt and PtO re-
duces the recombination of photogenerated electron–hole pairs. (3)
Fig. 11. UV photocatalytic degradation of Rhodamine B under different trap-
ping agents.
2
+
Pt and PtO nanoparticles provides an additional photocatalytic active
site and inhibits the oxidation of hydrogen during the reaction.
TiO -ZrO (C) on rhodamine B has reduced in varying degrees after
2
2
The cycle stability of the coral reef-like Pt/TiO
2
2
-ZrO (C) porous
adding the capture agent, indicating that the active species of Pt/TiO -
2
%
− %
composite was studied by photohydrolysis of hydrogen production
cycle. The results are shown in Fig. 10(b). It can be seen from Fig. 10(b)
ZrO (C) in the photocatalytic reaction system are mainly O2 , OH
2
+
and h .
that after the coral reef-like Pt/TiO
2
-ZrO
2
(C) porous composite material
As shown in Fig. 12(a), when ultraviolet light is irradiated on coral
reef-like Pt/TiO -ZrO (C) porous composites, the photon energy is
is recycled five times; its hydrogen production still maintains a high
level, indicating that the stability of the material is better. However, it
can be seen from Fig. 10(b) that the stability of the material decreases
after repeated cycles. The possible reason is that the noble metal Pt
2
2
greater than or equal to the band gap energy of TiO2 and ZrO . The
2
electrons in the valence band (VB) of TiO and ZrO are excited to the
2
2
conduction band (CB), and the electrons on the ZrO conduction band
2
deposited on the TiO
2
-ZrO
2
(C) composite produces hydrogen in pho-
(CB) are transferred to the conduction band of TiO , then it is captured
2
tolysis water. A certain oxidation occurred during the process, and Pt
oxide (PtO) is formed. The hydrogen production capacity of PtO is still
slightly different from that of Pt.
by the precious metal Pt. In addition, due to the lower Fermi level of Pt,
+
the hole (h ) generated in the valence band of ZrO is transferred to the
2
valence band of TiO . The electron trapping of TiO -ZrO (C) surface by
2
2
2
Pt as an electron trap not only reduces the recombination of photo-
generated electron–hole pairs, but also prolongs the retention time of
photogenerated electrons, thus improving the photocatalytic activity of
the composites.
3
.10. Possible photocatalytic reaction mechanism
In order to study the main active species of coral reef-like Pt/TiO
2
-
Fig. 12(b) shows the possible photocatalytic reaction mechanism of
coral reef-like Pt/TiO -ZrO (C) porous composites under visible light
ZrO
periments of rhodamine B degradation by Pt/TiO
were carried out in this paper. Among them, p-benzoquinone (BQ) was
used to capture superoxide radical ( O
ethylamine diamine (EDTA) was used to capture (h ), methanol
2
(C) porous composites in photocatalytic reaction, the capture ex-
2
2
2
-ZrO (C) composites
2
irradiation. Because both TiO2 and ZrO2 are broadband gap semi-
conductors, they almost do not absorb visible light, and hardly produce
electrons and holes when exposed to visible light. Compared with pure
TiO and ZrO under visible light, the photocatalytic properties of coral
%
−
2
), and ethylenediamine tetra-
+
2
2
%
(
CH
3
OH) to capture hydroxyl radical ( OH). It can be seen from Fig. 11
2 2
reef-like Pt/TiO -ZrO (C) porous composites were significantly en-
that in the absence of a capture agent, the degradation of rhodamine B
by the composite material reaches 95.0% after almost 120 min of ul-
traviolet light irradiation, and is almost completely degraded. The de-
gradation effect of the coral reef-like porous structure composite Pt/
hanced, mainly due to the SPR effect of Pt nanoparticles. Coral reef-like
Pt/TiO -ZrO (C) due to the SPR effect of metal Pt porous composites
can respond in the visible light region and generate hot plasma
2
2
10

M. An, et al.
Molecular Catalysis 475 (2019) 110482
2 2
Fig. 12. Possible photocatalytic reaction mechanism of Pt/TiO -ZrO (C).
electrons. The resulting hot plasma electrons transfer first to the con-
duction band of ZrO and then to the conduction band of TiO . In order
to return to the original state, Pt needs to accept electrons from the TiO
and ZrO valence bands. These factors can increase the charge carrier
lifetime and inhibit the recombination of electrons and holes. In addi-
tion, the near resonance energy transfer of Pt can accelerate the gen-
eration and separation of electron–hole pairs in TiO and ZrO .
2 2
In addition, under the irradiation of UV + vis light, the thermal
plasma electrons of Pt can be transferred to the conduction band of
of China (21376126), The Fundamental Research Funds in Heilongjiang
Provincial Universities, China (135209105), Government of
Heilongjiang Province Postdoctoral Grants, China (LBH-Z11108),
Postdoctoral Researchers in Heilongjiang Province of China Research
Initiation Grant Project (LBH-Q13172), Innovation Project of Qiqihar
University Graduate Education (YJSCX2016-ZD06), College Students'
Innovative Entrepreneurial Training Program Funded Projects of
Qiqihar University (201810232056) and Qiqihar University in 2016
College Students Academic Innovation Team Funded Projects.
2
2
2
2
ZrO
in Fig. 12(c). Pt nanoparticles play two roles in this photocatalytic
system. The first is to transfer electrons to the surface of ZrO and TiO
. The other is that Pt surface
plasmon photogenerated electrons can be injected into the conduction
bands of ZrO and TiO to improve the separation of electrons and
2 2 2
and TiO , thereby increasing the rate of formation of H , as shown
Appendix A. Supplementary data
2
2
,
+
and then react with H in water to form H
2
Supplementary material related to this article can be found, in the
online version, at doi:https://doi.org/10.1016/j.mcat.2019.110482.
2
2
holes. Therefore, this not only improves the absorption of visible light,
but also reduces the composite probability of photogenerated elec-
tron–hole pairs, thereby improving the photocatalytic activity of the
References
[1] Q.J. Xiang, J. Yu, M. Jaroniec, J. Am. Chem. Soc. 134 (2012) 6575–6578.
[
2] M.V. Carević, N.D. Abazović, T.B. Novaković, V.B. Pavlović, M.I. Comor, Appl.
coral reef-like Pt/TiO
2 2
-ZrO (C) porous composite.
Catal. B-Environ. 195 (2016) 112–120.
[
[
[
[
3] T.S. Atabaev, Front. Mater. Sci. 12 (2018) 207–213.
4] A. Ermete, Appl. Catal. B-Environ. 237 (2018) 491–503.
5] K. Maeda, K. Domen, J. Phys. Chem. Lett. 1 (2010) 2655–2661.
6] A. Khurshida, B. Nurlan, J. Mater. Chem. A Mater. Energy Sustain. 44 (2018)
21696–21718.
4
. Conclusion
Using polystyrene (PS) colloidal microsphere template technique,
the coral reef-like porous structure composite Pt/TiO -ZrO was suc-
cessfully prepared by sol–gel, vacuum impregnation and photoreduc-
tion. The composite Pt/TiO -ZrO (C) has a unique coral reef-like porous
[7] L. Wei, E. Ahmed, A. Dhaifallah, Chem. Soc. Rev. 22 (2018) 8203–8237.
[8] G.P. Anipsitakis, D.D. Dionysiou, Appl. Catal. B-Environ. 54 (2004) 155–163.
[9] J.Q. Zhang, L. Li, Z.X. Xiao, D. Liu, S. Wang, J.J. Zhang, Y.T. Hao, W.Z. Zhang, ACS
Sustain. Chem. Eng. 4 (2016) 2037–2046.
2
2
2
2
structure and high-efficiency lighting ability, which can effectively
capture light energy. At the same time, different energy levels between
[10] T. Sreethawong, S. Chavadej, S. Onsuratoom, Int. J. Hydrogen Energy 36 (2011)
246–5261.
5
[
11] S. Rtimi, C. Pulgarin, R. Sanjines, V. Nadtochenko, J.C. Lavanchy, J. Kiwi, ACS
TiO
2
and ZrO
2
semiconductors facilitate the transfer of photogenerated
to TiO , which improves the separation of photo-
Appl. Mater. Interfaces 7 (2015) 12832–12839.
[12] A. Imhof, D.J. Pine, Nature 389 (1997) 948–951.
carriers from ZrO
2
2
[
[
[
[
[
[
[
[
13] J.Q. Zhang, L. Li, J.J. Zhang, X.Y. Zhang, W.Z. Zhang, New J. Chem. 41 (2017)
generated charges. The plasmon resonance effect (SPR effect) of the
noble metal Pt can promote the migration mode of photogenerated
carriers and suppress the recombination of photogenerated electrons
and holes pairs. Meanwhile, the presence of PtO promotes the separa-
tion and transfer of electrons and holes, provides more active sites for
H production and inhibits the oxidation of H . Therefore, as a surface
2 2
reactive site, Pt and PtO further enhances its photocatalytic degradation
of organic pollution and photohydrolysis of hydrogen.
9
113–9122.
14] X.N. Ren, Z.Y. Hu, J. Jin, L. Wu, C. Wang, J. Liu, F. Liu, M. Wu, Y. Li, G.V. Tendeloo,
B.L. Su, ACS Appl. Mater. Interfaces 9 (2017) 29687–29698.
15] C.H. Lin, J.H. Chao, C.H. Liu, J.C. Chang, F.C. Wang, Langmuir ACS J. Surf. Coll. 24
(2008) 9907–9915.
16] J.E. Yoo, M. Altomare, M. Mokhtar, A. Alshehri, S.A. Althabaiti, A. Mazare,
P. Schmuki, J. Phys. Chem. C 120 (2016) 15884–15892.
17] Z. Lian, W. Wang, G. Li, F. Tian, K.S. Schanze, H. Li, ACS Appl. Mater. Interfaces 9
(
2017) 16959–16966.
18] Z. Jin, F. Wang, J.X. Wang, J.C. Yu, J.F. Wang, Adv. Funct. Mater. 23 (2013)
137–2144.
19] X.D. Huang, L. Li, Q.Y. Wei, W.Z. Zhang, Acta Phys. Chim. Sin. 29 (2013)
615–2623.
20] S. Kundu, J. Ciston, S.D. Senanayake, J. Phys. Chem. C 116 (2012) 14062–14070.
2
Acknowledgments
2
This study is supported by the National Natural Science Foundation
[21] A. Gołąbiewska, W. Lisowski, M. Jarek, Mol. Catal. 442 (2017) 154–163.
11

M. An, et al.
Molecular Catalysis 475 (2019) 110482
[
[
[
[
22] S.M. Chang, R.A. Dong, J. Phys. Chem. B 108 (2004) 18098–18103.
23] L.K. Ono, J.R. Croy, H. Heinrich, J. Phys. Chem. C 115 (2011) 16856–16866.
24] G. Anna, J. Walendziewski, Energy Fuels 19 (2005) 1143–1147.
zirconium titanium phosphate photocatalyst under visible light, J. Phys. Chem. C
111 (2007) 13437–13441.
[41] M.Z. An, L. Li, Y. Tian, H.L. Yu, Q.L. Zhou, RSC Adv. 8 (2018) 18870–18879.
[42] Z. Wu, Z. Sheng, Y. Liu, J. Hazard. Mater. 185 (2011) 1053–1058.
[43] C. Wang, H.Q. Fan, X.H. Ren, Y. Wen, W.J. Wang, Appl. Surf. Sci. 462 (2018)
423–431.
25] J.J. Murcia, M.C. Hidalgo, J.A. Navío, V. Vaiano, P. Ciambelli, D. Sannino, Today
1
96 (2012) 101–109.
[26] H. Chen, M. Tang, Z. Rui, H.J. Wang, Catal. Today 264 (2016) 23–30.
[
27] W. Meng, W. Zhen, B. Tian, J. Ma, G.X. Lu, Appl. Catal. B Environ. 236 (2018)
[44] M.C. Rosu, R.C. Suciu, M.D. Lazar, I. Bratu, Mat. Sci. Eng. B 178 (2013) 383–390.
[45] F. Theil, A. Dellith, J. Dellith, J. Colloid. Interfaces Sci. 421 (2014) 114–121.
[46] Y. Wei, X. Wu, Y. Zhao, L. Wang, Z. Zhao, X. Huang, J. Liu, J. Li, Appl. Catal. B-
Environ. 236 (2018) 445–457.
2
40–252.
[
[
[
[
[
28] Y. Ma, Z. Li, Appl. Surf. Sci. 452 (2018) 279–285.
29] Q. Zhang, W. Huang, B.Y. Chen, Chem. Eng. J. 343 (2018) 662–675.
30] T. Yang, L.L. Lou, W. Yu, ChemCatChem 9 (2016) 458–464.
31] Y. Wei, Z. Zhao, J. Liu, J. Catal. 317 (2014) 62–74.
[47] J.J. Li, S.C. Cai, E.Q. Yu, B. Weng, X.J. Chen, H.P. Jia, Y.J. Xu, Appl. Catal. B-
Environ. 233 (2018) 260–271.
[48] X. Wang, D. Chen, L. Cao, Y. Li, B.J. Boyd, R.A. Caruso, Appl. Mater. Interfaces 5
(2013) 10926–10932.
[49] S. Weon, J. Kim, W. Choi, Appl. Catal. B-Environ. 220 (2017) 1–8.
[50] H.J. Ahn, J.S. Lee, H.S. Kim, I. Hwang, J.T. Hong, J.H. Shin, C.H. Jung, J. Ind. Eng.
Chem. 65 (2018) 318–324.
32] S. Sakthivel, B. Neppolian, M.V. Shankar, Sol. Energy Mater. Sol. Cells 77 (2003)
6
5–82.
33] T.S. Wu, K.X. Wang, G.D. Li, S.Y. Sun, J. Sun, J.S. Chen, ACS Appl. Mater. Interfaces
(2010) 544–550.
[
2
[34] H.H. Ou, S.L. Lo, C.H. Liao, J. Phys. Chem. C 115 (2011) 4000–4007.
[35] S.N. Basahel, T.T. Ali, M.K. Mokhtar, Nanosc. Res. Lett. 10 (2015) 73–87.
[36] J.P. Contour, G. Mouvier, M. Hoogewys, C. Leclere, J. Catal. 48 (1977) 217–228.
[37] J.D. Rogers, V.S. Sundaram, G.G. Kleiman, S.G.C. Castro, R.A. Douglas,
A.C. Peterlevitz, J. Phys. F: Met. Phys. 12 (1982) 2097–2102.
[51] (a) M. Zhou, C.J. Hou, J.G. Chen, J. Jin, L.J. Ju, S. Xu, C. Yao, Z.Y. Li, J. Mater. Sci.
Mater. Electron. 29 (2018) 11972–11981;
(b) A. Léonard, J.L. Blin, B.L. Su, Chem. Commun. 20 (2003) 2568–2569.
[52] (a) A. Collins, D. Carriazo, S.A. Davis, S. Mann, Chem. Commun. 5 (2004)
568–569;
(b) Z.Y. Yuan, A. Vantomme, A. Léonard, B.L. Su, Chem. Commun. 9 (2003)
1558–1559.
[53] J. Liu, S. Qiao, S. Budi Hartono, Angew. Chem. 122 (2010) 4840.
[
[
[
38] G. Fan, X.Y. Ma, Y. Zhang, J. Wu, B. Xu, T. Sun, D. Gao, J. Bi, New J. Chem. 41
(
2017) 2793–2799.
39] J. Xing, H.L. Yu, B.J. Hai, Y. Wang, H.G. Yang, Int. J. Hydrogen Energy 39 (2014)
237–1242.
40] D. Jing, L. Guo, Efficient hydrogen production by a composite CdS/mesoporous
1
12