An Efficient Photocatalyst Based on Black TiO2 Nanoparticles and Porous Carbon with High Surface Area: Degradation of Antibiotics and Organic Pollutants in Water

Article abstract of DOI:10.1002/cplu.201900103

Porous carbon (PC) materials with high surface area can separate electron–hole pairs and adsorb organic pollutants more effectively. A series of nanocomposites were prepared by anchoring black TiO₂ nanoparticles (BTN) onto PC through a calcination process. Chemical and structural features of samples were examined by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The resulting adsorption-photocatalysis synergistic effect led to a dramatically improved photocurrent for BTN@PCs, thus indicating the high photocatalytic performance toward water-soluble organic species. For instance, the degradation of tetracycline under visible light reached 90 %, which is higher than that for activated carbon doped onto BTN (57 %) without any additional agents. Moreover, the degradation of other antibiotics (such as oxytetracycline and ciprofloxacin) and methylene blue were also studied, thus showing that this system has the potential to be used for water treatment.

Full text of DOI:10.1002/cplu.201900103

Accepted Article
Title: An Efficient Photocatalyst Based on Black TiO2 Nanoparticles
and Porous Carbon with High Surface Area: Degradation of
Antibiotics and Organic Pollutants in Water
Authors: Yu Fang, Yuanyuan Li, Feng Zhou, Peiyang Gu, Jiadi Liu,
Dongyun Chen, Najun Li, Qingfeng Xu, and Jian-Mei Lu
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An Efficient Photocatalyst Based on Black TiO Nanoparticles
2
and Porous Carbon with High Surface Area: Degradation of
Antibiotics and Organic Pollutants in Water
Yu Fang, [a] Yuanyuan Li, [a] Feng Zhou, [a] Peiyang Gu, [a] Jiadi Liu, [a] Dongyun Chen, [a] Najun Li, [a]
[
a]
[a]
Qingfeng Xu* and Jianmei Lu*
Abstract: Porous carbon (PC) materials with high surface area can
separate electron-hole pairs and adsorb organic pollutants more
effectively. A series of nanocomposites were prepared by anchoring
solve this crucial problem, recently, black TiO
2
has attracted
much attention because of the existence of oxygen vacancies
3
+
and Ti which significantly promote photocatalytic performance
[
13-15]. Therefore, many research groups have focused on the
2
black TiO nanoparticles (BTN) onto PC via a calcination process.
Chemical and structural features of samples were examined by X-
ray photoelectron spectroscopy (XPS), Raman spectroscopy,
powder x-ray diffraction (P-XRD), scanning electron microscopy
removal of water-soluble organic pollutants and the
photocatalytic splitting of water using black TiO and, nowadays,
2
most study are focused on simplifying the preparation process
and analyzing the relationship of morphology and catalytic
(SEM) and transmission electron microscopy (TEM) analyses. The
resulting adsorption-photocatalysis synergistic effect led to
a
performance [16-18]. Although black TiO
2
can resolve the problem
dramatically improved photocurrent for BTN@PCs, indicating the
high photocatalytic performance for water soluble organics species.
For instance, the degradation of tetracycline under visible light
reached 90%, which is higher than that for activated carbon doped
onto BTN (57%) without any additional agents. Moreover, the
degradation of other antibiotics (oxytetracycline, ciprofloxacin, etc)
and methylene blue were also studied, showing that this system has
the potential to be used for water treatment.
of weak absorption in the visible region, the high recombination
rate of electrons and holes remains an obstacle, limiting its
further application in the photocatalysis field [ . Therefore, it is
necessary to improve the charge separation and transport
19]
2
capability of black TiO .
for use practical applications [20-21]
High surface area porous carbon (PC) materials, a class of
carbon material possessing a high Brunauer–Emmett–Teller
(BET) surface area, has been demonstrated to be an ideal
catalyst supports, and promote the efficient separation of
electron-hole pairs [22-23]. Therefore, we believe that
combination of graphite PC and black TiO into one
a
2
Introduction
nanocomposite will allow for the fabrication of an excellent
photocatalyst for water remediation due to the following: (1)
Black TiO exhibits a strong absorption ability in the visible
2
region; (2) Graphite PC can be used as an excellent
photocatalyst support; (3) Graphite PC can increase the
adsorption capacity of target photocatalysts; (4) The efficiency of
charge separation and transport capability will be greatly
improved.
Photocatalysis has become
technology for the splitting of water, CO
degradation of pollutants in water owing to its operational
a
promising and powerful
2
conversion and the
[
1-
simplicity, catalyst recyclability, and its environmental benefits
.
4
]
As a key component of photocatalysis, photocatalyst should
be non-toxic, inexpensive, possess excellent stability against
corrosion, a strong absorption ability in the visible-light region,
have efficient charge separation and transport capabilities, and
be able to be recycled. Up to now, a large number of
photocatalysts have been developed but their shortcomings
such as weak absorption ability in the visible region, and the fast
recombination of electron-hole pairs, have hindered their further
practical application [5-7]. For example, TiO
is one of the most
2
widely used photocatalyst because of its stability towards light,
low cost, and environmental friendliness [8-10]. Nevertheless,
using pure TiO to degrade organic pollutants possesses a
2
particularly disadvantage in that the wide band gap (3.0-3.2 eV)
results in a response to UV light and poor efficiency [11-12]. To
[
a]
Y Fang, Y. Y. Li, F. Zhou, P. Y. Gu, J. D. Liu, Prof. D. Y. Chen, Prof.
N. J. Li, Prof. Q. F. Xu, Prof. J. M. Lu
Collaborative Innovation Center of Suzhou Nano Science and
Technology, College of Chemistry Chemical Engineering and
Materials Science
Scheme 1. Schematic illustration of the fabrication of BTN@PCs composites.
Soochow University
199 Ren’ai Road, Suzhou 215123 , P.R. China
E-mail: xuqingfeng@suda.edu.cn; lujm@suda.edu.cn
In this paper,
BTN@PCs) have been prepared by growing black TiO
nanoparticles onto a high surface area porous carbon backbone
a series of nanocomposites (named as
Supporting information for this article is given via a link at the end of
the document.
2
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using an operationally simple method (Scheme 1). BTN@PCs
were further selected as photocatalysts for the removal of
organic pollutants from simulated wastewater without any other
additives. In order to prepare an efficient photocatalyst,
BTN@PCs of different BTN ratios were investigated to optimize
the photocatalytic performance. The adsorption capacity and
photocatalytic activities of BTN@PCs were evaluated for the
removal of organic pollutants with the assistance of visible light.
Additionally, the stability and recyclability of BTN@PCs have
also been investigated in detail.
those of 5% BTN@PC and 15% BTN@PC are presented in
Figure S2a-b, respectively. For further confirmation, the high-
resolution transmission electron microscopy (HRTEM) image of
10% BTN@PC is shown in Figure 1e. The lattice fringes of BTN
are estimated to be 0.35 nm, in accordance with the (101) plane
(matching well with the P-XRD result). TEM and SEM images
coupled with the energy dispersive spectroscopy (EDS) image of
10% BTN@PC (Figure S2c-d) indicate not only BTN growth on
the surface of the PC, but also insertion into the pores and
channels, diminishing the surface area and porosity of the PC.
Figure 1d shows the UV-Vis diffuse reflectance spectra (DRS)
of BTN@PCs, BTN and PC. All of these materials show full
absorption in the entire UV-Vis region. The electron–hole pairs
may be formed rapidly under visible-light irradiation because of
the composite’s narrow bandgap.
Results and Discussion
The composites were characterized by P-XRD, Raman
spectroscopy and XPS, etc.
The P-XRD pattern (Figure 1a) shows the crystallinity of BTN,
PC and the BTN@PCs. The diffraction peaks of BTN@PC
appeared at 25.2, 37.6, 48.1°, matching well with the pure BTN
crystal planes of (101), (004), (200), which belong to anatase.
The (101) plane of BTN@PCs is the prominent facet which is
favourable to photocatalytic activity [24-25]. Raman spectroscopy
further demonstrates the successful incorporation of BTN onto
The chemical composition and chemical state information of
the composites were measured by XPS. The characteristic
energy spectrum of Ti, C, N and O of 10% BTN@PC is shown in
Figure 2a. Figure 2b shows that the Ti 2p1/2 and Ti 2p3/2 peaks
are located at binding energies of approximately 464.7 and
4
+
4
58.9 eV, respectively, corresponding to Ti . The Ti 2p1/2 and Ti
2p3/2 peaks of Ti3+ are located at 463.8 and 457.9 eV,
respectively [31]. The atomic fraction of the fitted Ti component
in 10% BTN@PC is approximately 1% by XPS peak area [32-33].
Compared with pure BTN (Figure S4), the peaks corresponding
to the Ti 2p orbital in 10% BTN@PC reveal an obvious redshift,
indicating that the chemical environment of the Ti atom at the
surface region of 10% BTN@PC is slightly different to that of
pure BTN. In addition, compared to that of BTN and PC (Figure
S3c and 4c), a new O 1s peak at 533.8 eV is observed, this
belongs to the C-O-Ti structure [34]. The spectrum of the C 1s of
3+
the carbon material (Figure 1b). There are two independent
peaks of located at 1329.9ꢀcm−1 (D band), which corresponds to
3
−1
sp deformation, and 1588.4ꢀcm (G band), which corresponds
to bond stretching of all sp2-bonded pairs in all samples [26]. In
addition, the Raman bands at 151.7, 393.0, 509.0 and 628.5
cm−1 of BTN can be attributed to the E
g
, B1g, A1g or B1g, and E
g
modes of the anatase phase, respectively [27]. However, these
bands are blue-shifted to some degree in of composites. For
instance, the Raman spectra of 15% BTN@PC showed that the
1
0% BTN@C is shown in Figure 2d. The binding energies at
84.8, 285.6 and 287.3 eV can be ascribed to graphite C-C, C-O
2
peaks at 161.2 (E
g
), 402.7 (B1g), 517.4 (A1g or B1g), and 638.2
and C=O bonds, respectively [35]. A new peak at 289.2 eV is
assigned to the C-O-Ti structure [36]. XPS analysis indicates the
) cm−1 with a blue-shift of 9.5, 9.3, 8.4 and 9.3 cm ,
−1
(E
g
respectively 28]. This illustrates an interaction between BTN and
[
the carbon material [29-30]
.
formation of a new interaction between TiO and carbon in the
2
composites.
Figure 1. XRD patterns (a), Raman spectra (b), UV-vis diffuse reflectance
spectra (d) of PC, BTN and BTN@PCs, TEM (c) and HRTEM (e) images of
Figure 2. XPS spectra of 10% BTN@PC: survey spectrum (a) and high-
resolution spectra of Ti 2p (b), O 1s (c) and C 1s (d) binding energies.
10% BTN@PC.
The SEM and TEM images show the morphology of the as-
In addition, for further confirmation of the presence of Ti3+ in
prepared nanocomposites. The size of the BTN is in the range of
-15 nm and the PC is porous (Figure S1c-d). Figure 1c shows a
typical TEM image of the as-prepared 10% BTN@PC, while
the BTN, the oxygen vacancies were verified by Electron Spin
Resonance (ESR). As shown in Figure S5, there is a strong
5
signal in BTN at g=1.993 [37]
.
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The images of the N
2
adsorption/desorption isotherms, and
exhibit better photocatalytic activity because of their better
electrochemical properties.
corresponding pore size distribution are shown in Figure S6. The
BTN@PCs exhibits a typical type IV isotherm with an obvious
hysteresis between the adsorption and desorption branches,
indicating the presence of mesopores in the BTN@PCs [38]. The
BET surface area, pore volume and average pore size of BTN,
PC and BTN@PCs are listed in Table 1. The BET values of the
BTN@PCs decrease with an increase in the doping amount of
BTN but it is still much higher than that of pure BTN. This
suggests that the BTN@PCs may provide more active sites for
adsorption, improving its photocatalytic behavior.
Figure 3. Photocurrent transient (a) and electrochemical impedance spectra
(b) of the synthesized materials.
Table 1. Porosity parameters of the as prepared-materials
Samples
names
S
BET
2
V
(pore)
3
D
(aver)
[nm]
The adsorption ability of the as-prepared materials was
investigated by adsorption tetracycline hydrochloride (TC) as a
model contaminant in aqueous solution (Figure 5a). In order to
(m /g)
2098.5
58.2
[cm /g]
1.0374
0.1081
0.8303
PC
1.9774
7.4207
2.3691
characterize the adsorption capacity of the photocatalysts, q
mg/g) was computed by:
=(C -C)V/W
and C (mg/L) are the initial concentration and
e
BTN
(
q
e
0
(1)
5%
1401.6
BTN@PC
where C
0
equilibrium concentration of TC, respectively, V (L) is the volume
of solution, and W (g) is the mass of photocatalyst.
1
0%
503.7
240.5
0.5365
0.3352
4.2599
5.5762
BTN@PC
As shown in Figure 4a, the PC possesses a strong adsorption
capacity of nearly 225 mg/g which is higher than pristine BTN
(33.75 mg/g) and P25 (14.3 mg/g). Following the insertion of
BTN into the carbon material, the adsorption capacity of the
composite materials decreases significantly, matching well with
the BET results.
15%
BTN@PC
The photoelectrochemical properties of the nanocomposite
materials and starting materials were investigated by
photocurrent and electrochemical impedance spectroscopy.
Commercial P25, activated carbon (AC) and 10% BTN@AC
(
BTN-anchored commercial activated carbon) were also studied
for comparison. Figure 3a shows the transient photocurrent
response of three BTN@PCs, BTN@AC, BTN, P25 and PC. In
the absence of light, the photocurrent of the pristine BTN is
higher than that of P25, while the photocurrent for 10%
BTN@AC shows only a slight increase compared with pure BTN.
The PC shows no obvious photocurrent. However, the
photocurrent density of the BTN@PCs improves dramatically,
with 10% BTN@PC possessing the highest photocurrent. This
can be ascribed to the excellent charge transport of PC which
optimizes the separation efficiency of the photogenerated
electrons and holes. During four on/off cycles of visible light
irradiation, all BTN@PCs displayed
a
relatively stable
photocurrent response, suggesting the satisfactory stability of
the photogenerated charge separation and strong photocatalytic
activity. It should be noted that the photocurrent for 15%
BTN@PC is lower than that for 5% and 10% BTN@PC. On the
one hand, the absorption ability of the BTN@PCs in the visible
region increases with an increase in the ratio of BTN; this is due
to the strong absorption ability of BTN in the visible region. On
the other hand, Table 1 shows that the BET surface area
decreases following an increase in BTN content, which is not
beneficial to photocatalytic activity. Thus, 10% BTN@PC
possesses the most suitable ratio of BTN. To confirm this result,
electrochemical impedance spectroscopy was conducted under
visible-light irradiation, as shown in Figure 3b. The 10%
BTN@PC presents the smallest arc radius, consistent with the
above photocurrent results, indicating that the BTN@PCs may
Figure 4. Adsorption performance for the removal of TC using various
photocatalysts (a), effect of initial concentration of TC on the adsorption by
10% BTN@PC (b), Freundlich isotherm (c) and Langmuir isotherm (d) for the
adsorption of TC onto 10% BTN@PC.
The adsorption capacity of 10% BTN@PC against four
different concentrations of TC solution is shown in Figure 4b and
the removal results are presented in histogram in Figure S7a. It
is known that the adsorption process plays an important role in
the first stage of the degradation process and will improve the
removal efficiency of the catalyst. Subsequently, the relatively
high initial uptake of TC during the first 20 mins is due to the
presence of a large number of adsorption sites. The Langmuir
and Freundlich models are shown in Figures 4c-d which
demonstrate the adsorption capacity for TC adsorption
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isotherms. The isotherm formula of the Langmuir isotherm
model (L-type) and Freundlich isotherm model (F-type) are the
following:
BTN@AC and BTN@PCs) for degrading TC in aqueous solution
are shown in Figure 5b. The removal efficiency of 10%
BTN@AC and 10% P25@PC are 57% and 52% respectively,
which are much lower than that of 10% BTN@PC. The
photocurrent and photocatalytic results prove the advantage of
using PC as a catalyst support. Figure 5c shows the degradation
q
e
=(q
= k
is the concentration of the adsorption equilibrium of
is the adsorbed number of TC for 10% BTN@PC, q is
the maximum adsorption capacity, k and k are the Langmuir
and Freundlich parameters, respectively, and n represents the
driving force intensity of adsorption [39]
m
k
L
C
e
)/(1+k
L
C
e
q
e
)
(2)
q
e
F
+C ^(1∕n)
e
(3)
Where C
TC, q
e
e
m
curves after adsorption-desorption equilibrium 3 h for the
L
F
removal of TC. The TC removal efficiency of pure BTN is 42%,
while the BTN@PCs catalysts were all better with removal
efficiencies of 90% for 10% BTN@PC, 82% for 5% BTN@PC
and 59% for 15% BTN@PC. The UV–vis absorption spectral
changes for TC in the presence of 10% BTN@PC are shown in
Figure S8.
In order to understand the reaction kinetics of the
photocatalytic reactions, the experimental data were fitted using
a Pseudo-first order model:
.
As shown in Figures 4c-d, the adsorption capacity of 10%
BTN@PC is well-matched with the Langmuir model in which R
2
is 0.992. There is a significant deviation of the R2 value in the
Freundlich model (0.4099). The results suggest that uptake of
TC using 10% BTN@PC is a monolayer adsorption process.
The pH is an important factor for the adsorption behavior of
photocatalysts [40]. The effect of pH values on TC adsorption
were investigated (Figure S7b). There is a maximum adsorption
capacity of 63.35 mg/g at pH 5. When the pH value is 11, the
adsorption capacity decreases to 35.84 mg/g.
Ln (C
is the concentration of the TC after initial adsorption-
desorption equilibrium, C is the concentration after simulated
visible-light irradiation, and k is the Pseudo-first order kinetics
0
/C
t
) = kt
(4)
where C
0
t
-1
The adsorption-photocatalytic performance for the raw and
composite materials was investigated by the removal of
antibiotics from aqueous solution under visible-light irradiation at
room temperature.
rate constant (min )
The determined curve coefficients are shown in Figure 5d. All
BTN@PCs exhibit a higher rate constant than that of pure BTN,
in which the rate constant of 10% BTN@PC possess the highest
-1
rate constant (0.00775 min ), which is approximately 6.62 times
-1
higher than that of pure BTN (0.00117 min ). The effect of 10%
BTN@PC concentration on photocatalytic performance was also
investigated. As shown in Figure S9a, different concentrations of
10% BTN@PC between 0.2 g/L and 1.4 g/L were chosen to
optimize photocatalytic performance. The removal efficiency of
the composites shows an increase going from a concentration of
0.2 g/L to 1.4 g/L, and the determined curve coefficients fit a
Pseudo-first order model, consistent with the above conclusion.
-1
The highest rate constant (0.01981 min ) for removal of TC
occurs at a 10% BTN@PC amount of 1.4 g/L. Additionally, the
photocatalytic ability of 10% BTN@PC at different initial TC
concentrations and pH values was also studied. As shown in
Figure S9c, when the initial TC concentration is 100 ppm, the
removal efficiency is only 50.8%. The low efficiency can be
ascribed to a reduction in the number of vacant active sites as
the concentration of TC increases. The pH is also an important
factor in the adsorption and photocatalytic process. The removal
efficiency is best at pH 5, matching well with the adsorption
results at different pH values.
Figure 5. Degradation experiments for the removal of various antibiotics with
BTN and 10 %BTN@PC under visible light (a), comparison of photocatalytic
activity for the removal of TC using various photocatalysts (b), Photocatalytic
activities of BTN, PC and BTN@PCs for the removal of TC under visible light
irradiation (c), Photocatalytic kinetics of BTN, PC and BTN@PCs for the
removal of TC (d).
To assess the potential of the photocatalyst in practical
applications, the removal of different antibiotics using 10%
BTN@PC and BTN is shown in Figure 5a. The removal
efficiencies of tetracycline, oxytetracycline, ciprofloxacin,
sulfisoxazole, carbamazepine and norfloxacin were 90%, 91%,
8
4%, 75%, 63% and 45%, respectively, indicating that the
Figure 6. Removal of MB with BTN and 10% BTN@PC under solar light
illumination (reaction condition: 6 mg photocatalyst, 10 ml of MB solution at
catalysts are effective for the removal of most antibiotics from
aqueous media. The removal efficiency of tetracycline and
oxytetracycline is better than that of the other antibiotics
because they possess many hydroxyl groups which can easily
interact with the BTN@PCs.
100 ppm) (a), consecutive cycles of photocatalytic degradation of TC (50 ppm)
over 10% BTN@PC (30 mg) under visible light (b).
A variety of factors influencing the photocatalytic removal of
TC were studied using 10% BTN@PC as a model. Firstly, the
removal efficiency of all related catalysts (P25, P25@PC, BTN,
The above results have demonstrated that the BTN@PCs
system exhibits excellent photocatalytic activity for the removal
of organic pollutants under visible-light irradiation due to its good
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adsorption capacity, relatively high carrier separation efficiency,
wide adsorption range, and synergistic effect between the BTN
and the porous carbon material.
adsorption under visible light irradiation. To better understand
the photocatalytic mechanism of the BTN@PCs composites, the
valence band (VB) of BTN and BTN@PCs were investigated by
XPS as shown in Figure S11. Furthermore, the conduction band
(CB) positions of the materials were determined by
Mott−Schottky plots as shown in figure S12. The CB values of
BTN, 5% BTN@PC, 10% BTN@PC and 15% BTN@PC are ca.
-0.81 eV, -0.85 eV, -0.83 eV and -0.80 eV, respectively, and the
calculated energy band gaps can be seen in Figure 7b 45-47].
In summary, a possible photocatalytic mechanism is illustrated
in Scheme 2. Under visible-light irradiation, the photogenerated
electrons are excited from the VB to the CB of BTN. Meanwhile,
the PC acts as an electron acceptor and the photoexcited
electrons in the CB of BTN can quickly transfer to the PC, which
ensures efficient charge transfer and at the same time retards
In order to extend the practical application of photocatalysts,
the removal of 100 ppm methylene blue (MB) with 10%
BTN@PC under solar light irradiation over 12 h was conducted,
as shown in Figure 6a. In the absence of catalyst under the
same conditions, the color of MB is practically unchanged. The
removal of MB can be easily observed by a color change. The
removal efficiency of 10% BTN@PC is almost 100%, better than
that of pure BTN. These results demonstrate that the light
source can be expanded to solar light, allowing for the practical
application of the photocatalysts.
In order to further confirm the reusability of the photocatalysts,
the removal of TC was conducted over five cycles with the as-
prepared 10% BTN@PC (Figure 6b). In each cycle, the
suspension was placed in the dark for 2 h to establish an
absorption-desorption equilibrium before irradiation. The
photocatalytic activity of 10% BTN@PC decreased only slightly.
This slight decrease may be due to the loss of photocatalyst
during the centrifugation and washing process. The results
indicate that 10% BTN@PC exhibits excellent stability
throughout the degradation process. In addition, the structure of
[
the charge recombination. The remaining photogenerated
−
electrons react with O
2
to generate •O
2
radical species which
can decompose the adsorbed TC into its corresponding
+
degradation products. Moreover, h , which possess oxidizing
ability in the VB of BTN, can directly oxidize TC to corresponding
degradation products. Direct detection of the final degradation
products
chromatography/mass spectrometry (HPLC-MS) shows the most
of TC is degraded into CO and water, however, some small
according
to
high-performance
liquid
10% BTN@PC after being recycled five times was determined
2
by XRD. The major XRD peaks corresponding to BTN remain
and no significant changes were observed when compared with
fresh and used catalysts, as shown in Figure S10. This indicates
organic molecule fragments are observed (Figure S13).
that the structure of the sample is well- preserved [41]
.
Figure 7. Effects of the addition of different scavengers on the degradation of
TC in the presence of the 10% BTN@PC composite (a) and energy band gaps
of BTN and BTN@PCs (b).
Scheme 2. Proposed mechanism for the removal of TC over the BTN@PC
composite.
In order to further confirm the specific active species of the
BTN@PCs composite in the photodegradation process, the
effects of the addition of radical scavengers on catalytic activity
were investigated, as shown in Figure 7a. Methanol was used to
quench ·OH, ethylenediaminetetraacetic acid (EDTA) was used
The synergistic effect between the physical adsorption and
photocatalytic degradation process results in improved catalytic
performance for the BTN@PCs. Thus, the photocatalytic
mechanism for BTN@PCs involves the following: adsorption of
organic pollutants by PC and adsorption of visible light by the
photocatalyst, resulting in charge transfer reactions to yield
radicals that decompose the TC. The adsorption process is
more efficient because of the PC, which increases the
concentration of pollutants around the photocatalyst and
improves the separation rate of photoelectrons, these are
important factors which contribute to an increase in degradation
efficiency.
+
-
to quench the holes (h ), p-benzoquinone was used as an ·O
2
scavenger and dimethyl sulf-oxide (DMSO) was used as an e-
scavenger [42-44]. Upon the addition of methanol and DMSO, no
obvious decrease in catalytic activity following adsorption was
-
observed, indicating that ·OH and e are not the main active
species. The addition of EDTA and p-benzoquinone resulted in a
significant decrease in catalytic activity after adsorption,
+
−
indicating that h and ·O
prove the existence of ·O
efficiency under N atmosphere. When the solution was sparged
with N to remove the O
dissolved in water to avoid the Conclusions
generation of radicals, no obvious decrease was observed after
2
is the main active species. To further
−, we investigated the degradation
2
2
2
2
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In summary, we have successfully fabricated BTN@PCs via a
calcination process. The removal efficiencies of the
nanocomposite materials are higher than that of pure BTN in the
presence of visible light radiation. In particular, the degradation
rate of TC with 10% BTN@PC is 6.62 times higher than that of
pure BTN. The improvement of the removal efficiency can be
contributed to the high surface area and effective charge
transfer of PC. We also showed that 10% BTN@PC is effective
for the removal of MB and other antibiotics from an aqueous
solution, suggesting the potential application of the new
photocatalyst for the removal of organic pollutants in water.
Fabrication of BTN@PCs. The BTN@PCs were obtained by
the in-situ growth of black TiO
backbone. To load BTN into PC, TiO
2
onto the porous carbon
precursor gel was firstly
synthetized. typical process: Titanium isopropoxide
3 2 4
(Ti(OCH(CH ) ) ) was added into 1-propanol (18 mL) under
2
A
stirring at room temperature, then, hydrochloric acid (37%, 1 mL)
and deionized water (1 mL) were added to the above solution.
The TiO precursor gel, in four different weight ratios, was fully
2
mixed with the carbon material with stirring for 30 mins at room
temperature. The mixtures were calcined at 550 °C under an
argon flow at a rate of 5 °C/min and held for 2 h. Finally, four
BTN@PCs of different BTN ratios (5% BTN@PC, 10%
BTN@PC, 15% BTN@PC and pure BTN) were obtained.
Photocatalytic activity measurements. The photocatalytic
activities of the composite materials were evaluated by
degrading TC under visible-light illumination. 30 mg
photocatalyst was dispersed in 50 mL of 50 ppm TC aqueous
solution. Before illumination, the suspensions were stirred in the
dark for 2 h to achieve an absorption-desorption equilibrium.
Then, the suspensions were irradiated by a Xenon lamp source
Experimental Section
Materials. Pyrrole was purchased from TCI (shanghai)
development Co. Ltd. 1,2-dichloroethane was purchased from
Aladdin. Anhydrous Iron (Ⅲ) chloride and Titanium isopropoxide
were purchased from shanghai macklin biochemical technology
Co., Ltd. (China). 1-Propanol, methanol (MeOH), Potassium
hydroxide (KOH), hydrochloric acid (HCl), terephthalic acid and
Tetracycline hydrochloride (TC) were purchased from sinopharm
chemical reagent co. ltd. All chemicals used without further
purification.
(
with a light filter > 420 nm) and a 3 mL suspension was
collected via filtration through a 0.45 um syringe filter to analyze
the concentration of TC. The suspensions were measured using
UV-vis spectrometer at λ= 354 nm.
Adsorption capability measurements. The adsorption
capability of TC was determined by dispersing photocatalyst
Instrumentation. The powder x-ray diffraction (P-XRD) patterns
were collected on an X’ Pert-Pro MPD to determine the
crystallographic structure of all materials. The BET surface area
and pore structure of the samples were measured by a
Micromeritics ASAP 2010 analyzer. Scanning electron
microscopy (SEM, Hitachi S-4700), transmission electron
microscopy (TEM, Tecnai G200) and HRTEM (Tecnai G2 F20 S-
TWIN) were used to determine the morphology and elemental
distribution of all materials. The elemental analysis (EA) was
performed on an Italian 1106 FT analyzer and X-ray
photoelectron spectroscopy of the materials was conducted in
an X-ray photoelectron spectrometer (XPS, ESCALAB MKⅡ) to
investigate the element composition. The diffuse reflectance
spectra (UV–vis, DRS Shimadzu UV-3600) and Raman spectra
(
typically 0.6 g/L) into 50 mL TC aqueous solution (typically 50
ppm) under stirring at room temperature. The adsorption
process was performed in the dark for 3 h and 3 mL of sample
was filtered through a 0.45 um syringe filter to remove the solid
catalysts. Afterwards, the suspensions were analyzed using a
UV-vis spectrometer at λ=354 nm.
Photoelectrochemical experiments. An electrochemical
workstation (CHI 660e, Shanghai, China) was used to measure
the photocurrent and electrochemical impedance spectroscopy
of the as-prepared materials, which were equipped with three
standard electrodes: Pt as the counter electrode and Ag/AgCl as
the reference electrode, the composite materials as the working
electrode, and Na
photocatalyst was dispersed in CH
2
SO
4
(0.1 M) as the electrolyte. The
CH OH by sonication to form
(
Renishaw Invia, UK, excitation wavelength = 532 nm) were
used to investigate the optical properties of the samples.
3
2
a 1 mg/mL suspension. The suspension was then dropped
directly onto the pre-treated ITO glass surface and dried by an
infrared baking lamp to obtain the working electrode. A Xenon
lamp (300 W, simulated sunlight) was used as a visible light
source.
Fabrication of hyperporous carbon material. The synthesis of
hypercrosslinked polymers was conducted according to previous
reports [48]. The EA of the hypercrosslinked polymers (HCP-Py)
are C: 54.85%; N: 11.78%; H: 5.491%. In brief, HCP-Py (1 g)
and KOH (4 g) were mixed into a solution of ethanol and water
(
V: V, 95:5) and stirred overnight at room temperature [49]. Next,
the solvent was removed by distillation under reduced pressure.
After the brown residue was dried under vacuum at 70°C for 8 h, Acknowledgements
the residue was placed into a nickel crucible which was further
inserted into a tube furnace. The furnace was purged with N
room temperature for 30 mins before the furnace was heated to
00 °C at a rate of 5 °C/min and held for 2 h. Finally, the furnace
was cooled to room temperature. The residue was washed
thoroughly with HCl and deionized water. Further
purification of the carbon materials was carried out by Soxhlet
extraction with methanol overnight. The resulting carbon
materials were dried under vacuum for 24 h at 70 °C.
2
at
This work was supported by the National Natural Science
Foundation of China (51773144, 21776190, 21336005) and
PAPD in Jiangsu Province.
7
1
M
2
Keywords: antibiotics • degradation • porous carbon • TiO •
photocatalysis • nanoparticles
[
[
1]
2]
H. Li, Y. Zhou, W. Tu, J. Ye, Z. Zou, Adv. Funct. Mater. 2015, 25, 998-
013.
2
Fabrication of black TiO NPs (BTN). The preparation of BTN
1
was carried out accorded to reported procedures [30]. The
structure was confirmed by P-XRD and the details are provided
in the results and discussion.
X. Zhuang, F. Zhang, D. Wu, N. Forler, H. Liang, M. Wagner, D. Gehrig,
M. R. Hansen, F. Laquai, X. Feng, Angew. Chem. 2013, 52, 9668-9672.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900103
FULL PAPER
[
3]
Z. Y. Tan, D.W.Y. Yong, Z. Zhang, H. Y. Low, L. Chen, W. S. Chin, J.
Phys. Chem. C 2013, 117, 10780-10787.
[38]
T. M. Onn, M. Monai, S. Dai, L. Arroyo-Ramirez, S. Zhang, X. Pan, G.
W. Graham, P. Fornasiero, R. J. Gorte, Appl. Catal., A 2017, 534, 70-
77.
[
[
4]
5]
N. Wu, Nanoscale 2018, 10, 2679-2696.
D. Lu, H. Wang, X. Zhao, K. K. Kondamareddy, J. Ding, C. Li, P. Fang,
ACS Sustainable Chem. Eng. 2017, 5, 1436-1445.
[39]
[40]
M. J. Ahmed, M. A. Islam, M. Asif, B. H. Hameed, Bioresour. Technol.
2017, 243, 778-784.
[
[
[
[
[
[
[
6]
L. Q. Jing, Y. Qu, B. Wang, S. Li, B. Jiang, L. Yang, F. Wei, H. Fu, J.
Sun, Sol. Energy Mater. Sol. Cells 2006, 90, 1773-1787.
F. X. Xiao, S. F. Hung, J. Miao, H. Y. Wang, H. Yang, B. Liu, Small
J. Y. Won, G. G. Gochev, V. Ulaganathan, J. Krägel, E. V. Aksenenko,
V. B. Fainerman, R. Miller, Colloids Surf., A 2017, 519, 161-167.
7]
[41] D. H. Quiñones, A. Rey, P. M. Álvarez, F. J. Beltrán, P. K. Plucinski,
2015, 11, 554-567.
Appl. Catal., B 2014, 144, 96-106.
8]
W. Yuan, L. Cheng, Y. An, S. Lv, H. Wu, X. Fan, Y. Zhang, X. Guo, J.
Tang, Adv. Sci. 2018, 5, 1700870.
[42]
[43]
[44]
C. Hu, T. Peng, X. Hu, Y. Nie, X. Zhou, J. Qu, H. He, J. Am. Chem.
Soc. 2010, 132, 857-862.
9]
Y. Xu, Y. Mo, J. Tian, P. Wang, H. Yu, J. Yu, Appl. Catal., B 2016, 181,
L. Shi, L. Liang, J. Ma, F. Wang, J. Sun, Catal. Sci. Technol. 2014, 4,
810-817.
758.
10]
11]
12]
C. K. Ngaw, C. E. Zhao, V. B. Wang, S. Kjelleberg, T. T. Yang, Tan, Q.
Zhang, S. C. Joachim Loo, Sustain. Energ. Fuels 2017, 1, 191-198.
J. C. Colmenares, R. S. Varma, P. Lisowski, Green Chem. 2016, 18,
D. Wang, Y. Duan, Q. Luo, X. Li, J. An, L. Bao, L. Shi, J. Mater. Chem.
2012, 22, 4847.
[45] S. Wang, B. Y. Guan, X. W. D. Lou, J. Am. Chem. Soc. 2018, 140,
5037-5040.
5736-5750.
T. Yang, J. Peng, Y. Zheng, X. He, Y. Hou, L. Wu, X. Fu, Appl. Catal.,
B 2018, 221, 223-234.
[46] L. Zhu, H. Li, P. Xia, Z. Liu, D. Xiong, ACS Appl. Mater. Interfaces 2018,
10, 39679-39687.
[
[
13]
14]
X. Chen, L. Liu, P. Y. Yu, S. S. Mao, Science 2011, 331, 746-750.
H. Song, C. Li, Z. Lou, Z. Ye, L. Zhu, ACS Sustainable Chem. Eng.
[47] P. Palacios, I. Aguilera, K. Sánchez, J. C. Conesa, P. Wahnón, Phys.
Rev. Lett. 2008, 101, 046403.
2017, 5, 8982-8987.
[48]
J. M. Lee, M. E. Briggs, T. Hasell, A. I. Cooper, Adv. Mater. 2016, 28,
[
[
[
[
[
[
[
[
15]
16]
17]
18]
19]
20]
21]
22]
Z. Wei, Y. Liu, J. Wang, R. Zong, W. Yao, J. Wang, Y. Zhu, Nanoscale
9804-9810.
2015, 7, 13943-13950.
[49] C. Zhang, R. Kong, X. Wang, Y. Xu, F. Wang, W. Ren, Y. Wang, F. Su,
K. Zhang, W. Zhou, X. Zhang, B. Sun, L. Wang, K. Pan, B. Jiang, G.
Tian, H. Fu, Appl. Catal., B 2017, 206, 336-343.
J. X. Jiang, Carbon 2017, 114, 608-618.
W. Zhou, W. Li, J. Q. Wang, Y. Qu, Y. Yang, Y. Xie, K. Zhang, L.
Wang, H. Fu, D. Zhao, J. Am. Chem. Soc. 2014, 136, 9280-9283.
K. Du, G. Liu, X. Chen, K. Wang, Electrochim. Acta 2018, 277, 244-
254.
F. Dong, S. Guo, H. Wang, X. Li, Z. Wu, J. Phys. Chem. C 2011, 115,
13285-13292.
M. Li, B. Lu, Q. F. Ke, Y. J. Guo, Y. P. Guo, J. Hazard. Mater. 2017,
333, 88-98.
J. Pan, Z. Dong, B. Wang, Z. Jiang, C. Zhao, J. Wang, C. Song, Y.
Zheng, C. Li, Appl. Catal., B 2019, 242, 92-99.
X. Zhuang, F. Zhang, D. Wu, N. Forler, H. Liang, M. Wagner, D.
Gehrig, M. R. Hansen, F. Laquai, X. Feng, Angew. Chem. 2013, 52,
9668-9672.
[
[
23]
24]
Y. Yang, K. Chiang, N. Burke, Catal. Today 2011,178, 197-205.
J. Yu, J. Low, W. Xiao, P. Zhou, M. Jaroniec, J. Am. Chem. Soc. 2014,
136, 8839-8842.
[
25] N. Wu, J. Wang, D. N. Tafen, H. Wang, J. G. Zheng, J. P. Lewis, X. Liu,
S. S. Leonard, A. Manivannan, J. Am. Chem. Soc. 2010, 132, 6679-
6685.
[
[
26] J. Zhou, M. Wang, X. Li, Appl. Surf. Sci. 2018, 462, 444-452.
27] W. F. Zhang, Y. L. He, M. S. Zhang, Z. Yin, Q. Chen, J. Phys. D: Appl.
Phys. 2000,33, 912.
[
28] C. Y. Xu, P. X. Zhang, L. Yan, J. Raman Spectrosc. 2001, 32, 862-865.
29] J. Yang, D. Chen, Y. Zhu, Y. Zhang, Y. Zhu, Appl. Catal., B 2017, 205,
[
228-237.
[
[
[
[
[
[
[
[
30] L. L. Qu, N. Wang, Y. Y. Li, D. D. Bao, G. H. Yang, H. T. Li, J. Mater.
Sci. 2017, 52, 8311-8320.
31] M. C. Wu, K. C. Hsiao, Y. H. Chang, S. H. Chan, Appl. Surf. Sci. 2018,
4
30, 407-414.
32] B. Gong, X. Luo, N. Bao, J. Ding, S. Li, J. Yi, Surf. Interface Anal. 2014,
6, 1043-1046.
4
33] G. Liu, J. A. Rodriguez, J. Hrbek, B. T. Long, D. A. Chen, J. Mol. Catal.
A: Chem. 2003, 202, 215-227.
34]
X. Fu, H. Yang, G. Lu, Y. Tu, J. Wu, Mater. Sci. Semicond. Process.
015, 39, 362-370.
35] B. Gao, P. S. Yap, T. M. Lim, T. T. Lim, Chem. Eng. J. 2011, 171,
098-1107.
2
1
36]
A. Omri, S. D. Lambert, J. Geens, F. Bennour, M. Benzina, J. Mater.
Sci. Technol. 2014, 30, 894-902.
37]
X. Pan, M. Q. Yang, X. Fu, N. Zhang, Y. J. Xu, Nanoscale 2013, 5,
3601-3614.
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Facile in-suit growth of BTN on porous
carbon material (PC) for efficient
Yu Fang, Yuanyuan Li, Feng Zhou,
Peiyang Gu, Jiadi Liu, Dongyun Chen,
Najun Li, Qingfeng Xu* and Jianmei Lu*
photocatalytic
antibiotics.
irradiation,
degradation
of
Under
the
visible-light
photogenerated
Page No. – Page No.
electrons of BTN react with O
2
to
An Efficient Photocatalyst Based on
Black TiO Nanoparticles and Porous
2
−
radical species and h+
generate •O
2
which can decompose the adsorbed
antibiotics into its corresponding
degradation products. Meanwhile, PC,
as a supported material displays rapid
transport of charge carriers and
provided more active sites.
Carbon with High Surface Area:
Degradation of Antibiotics and
Organic Pollutants in Water
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