Enhancing Photocatalytic Activity of Cu2O in Degradation of Sulphonic Acid-Based Dye

Article abstract of DOI:10.1134/S1070427219010208

In the present investigation, we synthesized copper (I) oxide nanoparticles (NPs) by the coprecipitation method. The obtained materials were characterized by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDXA), field emission scanning electron microscopy (FESEM), Transmission Electron Microscopy (TEM), and the Brunauer-Emmett-Teller (BET)/Barrett-Joyner-Halenda (BJH) Method. Surface areas and the average particle size were evaluated to be around 4.20 ± 0.04 m² g^?1 and 28 nm, respectively. Then, Ag/Cu₂O NPs were synthesized by the same process, examined by X-ray diffraction, and the average particle size obtained was around 118 nm. The photocatalytic degradation of [1,3-Amino phenyl [4-Sulphonic acid][2,6-Dis azo phenyl] 4,4′sulphato ethyl [6′sulpho] ester of Sulphonic acid] (COG-423) was investigated with Cu₂O and TiO₂ NPs, Cu₂O Microparticles (Micro-Ps) and Ag/Cu₂O NPs under UV-C irradiation in the presence of hydrogen peroxide as auxiliary oxidant with three parameters including dopant concentration, intensity, and time, as the obtained experimental results showed a good agreement with theoretical values and succeeded to calculate the optimal conditions. Degradation efficiency with Cu₂O Micro/NPs under UV-C irradiation (32 W), for 30 min. were determined to be 20.0% and 91.4% respectively, while for the synthesized TiO₂ and Ag/Cu₂O, NPs were 99.9%. The photocatalytic activity order was of the following nature: Ag/Cu₂O ～ TiO₂ NPs > Cu₂O NPs > Cu₂O Micro-Ps.

Full text of DOI:10.1134/S1070427219010208

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2019, Vol. 92, No. 1, pp. 141−149. © Pleiades Publishing, Ltd., 2019.
CATALYSIS
Enhancing Photocatalytic Activity of Cu2O
in Degradation of Sulphonic Acid-Based Dye1
M. Sepahvanda, R. Fazaelib,*, S. Jameh-Bozorghic, and A. Niazia
a Department of Chemistry, Islamic Azad University, Arak Branch, Arak, Iran
b Department of Chemical Engineering, Faculty of Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
*e-mail: r_fazaeli@azad.ac.ir
c Department of Chemistry, Faculty of Science, Hamedan Branch, Islamic Azad University, Hamedan, Iran
Received November 22, 2018; revised November 23, 2018; accepted February 4, 2019
Abstract—In the present investigation, we synthesized copper (Ι) oxide nanoparticles (NPs) by the coprecipitation
method. The obtained materials were characterized by X-ray diffraction (XRD), energy-dispersive X-ray analysis
(EDXA), field emission scanning electron microscopy (FESEM), Transmission Electron Microscopy (TEM), and
the Brunauer–Emmett–Teller (BET)/Barrett–Joyner–Halenda (BJH) Method. Surface areas and the average particle
size were evaluated to be around 4.20 ± 0.04 m2 g–1 and 28 nm, respectively. Then,Ag/Cu2O NPs were synthesized
by the same process, examined by X-ray diffraction, and the average particle size obtained was around 118 nm.
The photocatalytic degradation of [1,3-Amino phenyl [4-Sulphonic acid ][2,6-Dis azo phenyl] 4,4'sulphato ethyl
[6'sulpho] ester of Sulphonic acid ] (COG-423) was investigated with Cu2O and TiO2 NPs, Cu2O Microparticles
(Micro-Ps) and Ag/Cu2O NPs under UV-C irradiation in the presence of hydrogen peroxide as auxiliary oxidant
with three parameters including dopant concentration, intensity, and time, as the obtained experimental results
showed a good agreement with theoretical values and succeeded to calculate the optimal conditions. Degradation
efficiency with Cu2O Micro/NPs under UV-C irradiation (32 W), for 30 min. were determined to be 20.0% and
91.4% respectively, while for the synthesized TiO2 and Ag/Cu2O, NPs were 99.9%. The photocatalytic activity
order was of the following nature: Ag/Cu2O ~ TiO2 NPs > Cu2O NPs > Cu2O Micro-Ps.
Keywords: Cu2O NPs, Cu2O micro-Ps, [1,3-amino phenyl[4-sulphonic acid[2,6-dis azo phenyl]4,4'sulphato
ethyl[6'sulpho]ester of sulphonic acid, Ag/Cu2O NPs and photocatalytic degradation
DOI: 10.1134/S1070427219010208
INTRODUCTION
wavelengths above 500 nm [10, 11]. This composition as
a P-type semiconductor with a band gap 2.0–2.2 eV [12],
has unique optical, electronic and catalytic properties
[13, 14], with a great potential for use in solar cells [15],
electrode tools [16, 17], gas sensors [18, 19], and organic
pollutant degradation under UV and visible irradiation
[20–22].
Industrial development in recent years has been
one of the most important factors behind an increase in
pollutants affecting human life and that of other living
organisms. One of the biggest sources of air pollution is
wastewater from factories that do not have any proper
means to dispose of their waste material, resulting in
pollutants being directly released into the environment
[1–5]. Therefore, the use of photocatalysts is a new
method to remove toxic pollutants and chemicals from
the air and sewage [6, 7].
Various morphologies of Cu2O, including nanospheres
and nanowires, have also been synthesized [23–28].
This oxide is known as an efficient, cost-effective, and
eco-friendly photocatalyst for the degradation of organic
compounds [29–31].
Cu2O is a very suitable option for photocatalytic
activities [8, 9]. The above compositions of nanoparticles
have optical clarity and high absorption coefficient at
In the photocatalytic oxidation process, free radicals
are generated in the semiconductor, leading to the
destruction of substances absorbed by the photocatalyst
surface.
1 The text was submitted by the authors in English.
141

142
SEPAHVAND et al.
Among of the various semiconductors cited in the
both made by SIGMA Co., while Cu2O micro-Ps were
purchased from RIEDEL Co. All materials were of an
analytical grade and used without further purification.
scientific literature, TiO2 is the most suitable compound for
various environmental applications. This nanocomposite
shows band gap absorption in the ultraviolet region only
[32]. There are limitations in the TiO2 synthesis method,
such as its high cost, while the synthesis of Cu2O and/Ag
Cu2O NPs, owing to its simplicity, cost-effectiveness, and
relatively high efficiency, is a suitable alternative to TiO2.
The X-ray diffraction pattern of pure Cu2O and Ag/
Cu2O NPs was applied by the STOE Model of the STADIP
system using the mechanism of light transmission. The
morphology and structure of the synthesized nanoparticles
with (FESEM) and Ag, wt %, were determined by
technique (EDXA) using scanning electron microscopy
of TESCAN Model of MIRA3. Absorption values were
obtained to calculate the efficiency of the destruction by
a UV-vis UVIKON923 spectrophotometer.
Sha Tao and co-workers synthesized Ag/Cu2O NPs
with core-shell structure. According to the study, an in-
crease in the photocatalytic properties of nanoparticles
was observed in the above-mentioned compound com-
pared to pure copper oxide nanoparticles. This increase
occurred in the photocatalytic properties of the larger
BET surface area and separation efficiency. Experiments
showed that superoxide anion radicals and holes had a
vital role in the photocatalytic degradation of methyl
orange by Ag/Cu2O with a core-shell structure [33].
The synthesis of Cu2O NPs. Copper oxide of 2.00 g
was added to 50 mL of distilled water and stirred for
about 30 min. At room temperature until a transparent
blue solution was reached.
Sodium hydroxide of 8.00 g was added to 40 mL of
distilled water, and stirred for 20 min at room temperature.
The resulting solution was added drop by drop to the
solution of copper acetate to make a colloidal phase. The
solution was stirred for 30 min at room temperature to
make cupper hydroxide.
In addition, Xuexiang Hu and co-workers studied the
impact of Cu2O/Ag/AgBr compound on alumina. The
obtained results indicated photocatalytic activity and high
stability in the degradation of organic pollutants under
visible light irradiation and the release of metal ions
during the degradation of the pollutants [34].
Ascorbic acid of 15.6 g was added to 40 mLof distilled
water and stirred for 30 min. The solution was added
drop by drop to the previous solutions, and a change in
color from green to orange indicated the formation of
Cu2O particles.
Yang Jianbo et al. successfully synthesized Ag/
Cu2O by an affordable solution. They have shown that
the formation of the Ag/Cu2O microcomposite was
significantly influenced by the concentration of the silver
nitrate solution, and an increase in its concentration
strengthened the optical absorption of the composites.
This effect was used for photocatalytic degradation of
methyl orange under visible light irradiation. According
to studies, this method can be used to decompose sewage
waste in industry [35].
The solution was stirred for 45 min, then the filter
was washed twice with distilled water, and the prepared
precipitate was placed in a vacuum oven at 150°C for 4 h.
The synthesis of Ag/Cu2O NPs. Minitab-16
software was used to achieve the accurate % w/w of Ag,
which ultimately resulted in 6 and 12% of the above-
mentioned % w/w.
The present study investigates the effect of the doping
ofAg on Cu2O NPs to enhance the photocatalytic activity
and degradation efficiency. COG-423 was studied and,
finally, the optimum conditions with three parameters
including dopant concentration, intensity, and time were
calculated. The effect of pH was not investigated because
no significant effect was observed in the degradation
efficiency within the desired range, but the photocatalyst
was synthesized for application in industries because of
the uncontrollable effects of pH changes.
Silver nitrate, weighing 0.078 g (6%) or 0.157 g
(12%) was added to 40 mL of distilled water and stirred
for 30 min until the solution became completely trans-
parent. Tri-sodium citrate weighing 0.107 g was added
to 25 mL of distilled water and stirred for 30 min. The
prepared solution was added drop by drop to the silver
nitrate solution and stirred for 2 h at room temperature
in order to provide metallic silver. The resulting solution
was added drop by drop to a solution of copper oxide in
the synthesis process and stirred for 24 h at room tem-
perature, and the solution was filtered and washed with
distilled water. Ag/Cu2O NPs were, finally, obtained by
drying the precipitate in a vacuum oven at 150°C for 4 h.
EXPERIMENTAL
Materials. Copper acetate was used as a precursor of
copper to prepare the catalyst ascorbic acid d: 1.65 g cm–3,
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ENHANCING PHOTOCATALYTIC ACTIVITY OF Cu2O
143
Photocatalytic procedure. In the photocatalytic deg-
The goal is to optimize y.
radation processes, organic pollutants disappear under
radiation and in the presence of oxidants and semicon-
ductors. To study this effect, solutions were prepared as
follows:
It is assumed that the independent variables are
continuous and controllable by experiments with
negligible errors. Proper approximation functions for
communication between independent variables and the
response surface are essential.
COG-423 solution (150 mL200 ppm), 30 mLhydrogen
peroxide 0.05 M (as auxiliary oxidant), 0.2 g Cu2O (or
Ag/Cu2O), and 20 mL of distilled water were mixed and
placed into the reactor vessel. Photocatalytic degradation
efficiency of the catalyst was calculated according to
the following general equation extracted from the Beer–
Lambert law:
Usually, a second-order polynomial equation is
considered a perfect RSM model:
k
k
k
k
y = β0 + Σ(βixi) Σ βiixi2 + Σ Σβii xi xj + ε.
(3)
i = 1
i = 1
j = 1, i < j
In this equation, y is response (photocatalytic effect on
amount of destruction), β0, βii, βii, and βij are regression
coefficients, xi is the coded independent variable and k
is the number of variables [38].
A0 – Aα
Degradation, % –––––––– × 100,
(1)
Aα
where Ao and Aα are absorptions of the initial and final
Among the several methods of response surface
design, the Box–Behnken method studies the variable
interaction effect on response, because this technique
requires a minimum number of tests to run.
solutions respectively.
Experimental design Experimental design is a
method for systematically conducting a series of tests
to determine the importance of the process factors,
interactions, and their control in achieving an optimal
response. The purpose of this procedure is to obtain
reliable and appropriate results based on a limited number
of observations. For this purpose, experimental design
uses statistical tools.
The Box–Behnken design (BBD) is one of the
experimentaldesignsfortheresponsesurfacemethodology
that was developed by George Box and Donald Behnken.
The above plan is one of the second-order equation
convertibles based on the combining of the two-level
factorial and partial-block equations. In each block,
there are a number of points of variable designs and a
repeatable central point. The Box–Behnken design, along
with RSM, is used to optimize the physical, chemical, and
biological processes.
The main instruments in this field are divided into
two groups that include design tools and test analysis.
In the field of experimental design, there are methods
such as full factorial methods based on Latin squares,
and in the field of test analysis, variance analysis and its
derivatives and regression analysis are the most important
tools [36, 37].
The number of required tests for the BBD method is
calculated with the following equation:
There are four types of test analysis:
– Mixture experiments;
– Factorial design;
N = k2 + k + cp,
(4)
where k is the number of variables and cp shows the
number of repeats in the central points.
– Combined design;
Photocatalytic degradation by different catalysts with
respect to time has been calculated as following order:
Ag/Cu2O ~ TiO2 NPs (99.99%) > Cu2O NPs (91.4%) >
Cu2O Micro-Ps (20%).
– Response surface.
The response surface methodology (RSM) is used
to optimize the process of multivariate testing with the
minimum number of tests. Test analysis by the minimum
number of tests leads to the saving of time, materials, and
laboratory work.
RSM is used to analyze and optimize photocatalytic
degradation. The impact of different variables such as
dopant concentration, light intensity, and the duration of
irradiation were analyzed by design techniques.
If all variables are measurable, the response surface
is calculated by the following formula:
This work uses the Box–Behnken design for 15 tests
and used three replicated central points.
y = f(x1, x2, … , xk).
(2)
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144
SEPAHVAND et al.
120
100
80
60
40
20
0
y = 1.2748x ‒ 25 498
R2 = 0.985
40 50 60 70 80 90 100 110 120
Experimental (actual)
Contour plot of R vs. light, Ag%
(a)
(a')
Surface plot of R vs. light, Ag%
30
25
20
15
10
R
100
75
50
30
20
10
0
4
8
12
0
2
4
6
8 10 12
Ag%
Contour plot of R vs. time, Ag%
(b)
Surface plot of R vs. time, Ag%
30
25
20
15
10
(b')
R
105
90
75
30
60
20
0
4
10
8
12
0
2
4
6
8 10 12
Ag%
Contour plot of R vs. time, light
30
(c)
(c')
Surface plot of R vs. light, Ag%
25
20
15
10
R
70
60
30
50
10
20
20
Light
10
30
10 15 20 25 30
Fig. 1. The contour plots of (R: response) (a) showing simultaneous influence of dopant concentration and irradiation intensity (w) on
degradation, (b) showing the interaction between dopant concentration and time (min), (c) showing the interaction between irradiation
intensity and time along the response surface plots of (R: response), (a') showing simultaneous influence of dopant concentration and
irradiation intensity on degradation, (b') showing the interaction between dopant concentration and time, (c') showing the interaction
between irradiation intensity and time.
The design points, besides the experimental and pre-
dicted values of the organic pollutants’photodegradation,
are given in the table.
Figures 1a and 1a' represent the simultaneous effect
of dopant (Ag) concentration and UV light intensity on
the degradation efficiency of organic pollutants.
By plots, the experimental degradation data versus
predicted values, and the straight-line equation of these
amounts, R2 = 0.985, was calculated that representing the
coordination and compliance between the design methods
and experiments.
According to the figures, an increase in the dopant
(Ag) concentration to 6% results in a decrease in the
degradation efficiency, and its subsequent increases
up to 12%, have an inverse outcome on the process.
For example, when light intensity is 32 W and dopant
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ENHANCING PHOTOCATALYTIC ACTIVITY OF Cu2O
145
Ag%
12.0
[11.3939]
0.0
Light
32.0
[32.0]
8.0
Light
30.0
[30.0]
10.0
Optimal D
0.99767
high
cur
low
Composite
desirability
0.99767
R
Targ: 99.990
y = 99.8742
d = 0.99767
Fig. 2. Optimal condition of photocatalytic degradation by Ag/Cu2O NPs.
concentration is 12%, the degradation efficiency is about
99.9%, while the degradation efficiency is 72.5% when
the light intensity and dopant concentration are 32 W and
6%, respectively.
active crystal sites and degradation efficiency. Figure 2
is shown optimal conditions as per obtained results by
experimental design with Ag%, light and time param-
eters as [12%], [32 W] and [30 min], respectively. The
efficiency of reaction was calculated 99.99% that showed
good agreement with experimental results.
The correlation between light intensity and degradation
efficiency is a direct relationship because, in a higher
intensity, more crystals are exposed to the light, so more
crystalline sites are activated.
Table
Figures 1b and 1b' show the interaction between
dopant (Ag) concentration and the irradiation time.
According to the preceding descriptions, at lower
dopant concentrations, degradation efficiency was
inversely related to the concentration, while at higher
concentrations, degradation efficiency showed a reverse
trend, so that the maximum efficiency was seen when the
dopant concentration was about 12%.
Coded levels
Photodegradation %
experimental
Run Blk
A
–
–
–
+
+
0
+
–
0
+
0
0
0
0
0
B
0
0
–
–
0
–
0
+
+
+
–
0
0
0
+
C
–
+
0
0
–
–
+
0
+
0
+
0
0
0
–
predicted
80.831
89.244
74.004
87.319
90.146
39.615
100.649
91.151
63.265
98.556
47.542
50.85
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
81.49
90.13
72.57
87.43
89.26
50.39
99.99
91.04
72.49
99.99
58.09
60.92
60.74
60.89
61.73
3
4
5
6
The influence of time on degradation efficiency was
direct; hence, the degradation efficiency is the maximum
at 30 min. because crystals are exposed to irradiation for
a longer time, enabling the activation of more crystalline
sites.
7
8
9
10
11
12
13
14
15
Figures 1c and 1c' show the effects of both severity
and time on degradation efficiency of organic pollutants.
These two variables have a similar effect on the degrada-
tion efficiency. As already mentioned, by increasing the
intensity and time, crystals are exposed to large amounts
of light rays for a long period, increasing the number of
50.85
50.85
52.277
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146
SEPAHVAND et al.
14000
12000
10000
8000
6000
4000
2000
0
Cu2O
Ag
b
(111)
(200)
a
(311)
(220)
0
10 20
30
40 50 60
Angle, deg
70 80
90 100
Fig. 3. X-ray diffraction pattern of (a) Cu2O and (b) Ag/Cu2O NPs.
(a)
(b)
(c)
(d)
Ag
Cu2O
Fig. 4. FESEM imaging of (a) Cu2O NPs with resolution of 200 nm, (b) Ag/Cu2O NPs with resolution of 1 μm, (c) resolution of
100 nm, (d) TEM imaging of Ag/Cu2O NPs.
RESULTS AND DISCUSSIONS
from the cubic to the hexagonal form. This means the
formation Ag/Cu2O NPs prevents Cu2O NPs crystal
growth.
X-ray diffraction (XRD) patterns. Figures 3a and
3b show the X-ray diffraction pattern for Cu2O and
Ag/Cu2O NPs respectively. As a result of the doping
of Ag on Cu2O NPs, a crystalline phase change occurs
Figure 3a shows the X-ray diffraction (XRD) pattern
of Cu2O NPs. In the (XRD) pattern, there are four main
peaks at angles of diffraction 36.49, 42.37, 61.45, and
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ENHANCING PHOTOCATALYTIC ACTIVITY OF Cu2O
147
73.4° that correspond to with crystal faces with Miller
indices (111), (200), (220) and (311), respectively.
4000
3500
3000
2500
2000
1500
1000
500
CuLα
In the Ag/Cu2O X-ray diffraction pattern (Fig. 3b),
there are four major peaks at angles of diffraction 36.41,
42.33, 61.31, and 73.37° that correspond to crystal
faces with Miller indices (111), (200), (220) and (311),
respectively. This pattern represents the cubic phase for
Cu2O NPs.
OKα
AgLβ
AgLα
Two cubic crystalline phases, Cu2O and Ag, in the
X-ray diffraction pattern ofAg/Cu2O NPs were obtained.
The diffraction peak width of Ag/Cu2O NPs compared
to the Cu2O crystalline structures represented smaller
crystalline structures in Ag/Cu2O NPs. As a result of the
Ag doping on Cu2O NPs, the crystalline phase changed
from cubic to hexagonal, preventing the growth of Cu2O
NPs crystals.
CuKα
CuKβ
0
0
5
10
Energy, keV
Fig. 5. Energy-dispersive X-ray analysis results of Ag/Cu2O
NPs.
Using the Debye–Scherrer equation (Eq. 5), the mean
sizes of Cu2O cubic andAg/Cu2O hexagonal nanocrystal
were calculated to be 28.21 and 118.07 nm, respectively.
8
Desorption
6
4
2
0
kλ
B = ––––––––––,
Lcos θ
(5)
Adsorption
1 1.2
0
0.2
0.4
0.6
0.8
where B represents the crystal size, k = constant parameter
(0.89), λ = the wavelength of the cathode, L = the full
width at half maximum (FWHM) and θ is desired peak
angle.
Relative pressure p/p0
Fig. 6. Cu2O NPs hysteresis loop.
The results of imaging and EDXA represent the Ag
surface accumulation of Cu2O NPs.
Morphology analysis. FESEM and TEM imaging
were used to observe the morphology of synthesized
nanoparticles.
BET–BJH test. Based on the results of the BET–BJH
test, Cu2O particle surface area was calculated as 4.20 ±
0.04 m2/g and the volume percentage of pores in the
three-phase micro, meso, and macro was 21.76, 72.90,
and 5.34%, respectively.
Figure 4a shows the FESEM imaging of Cu2O NPs
with an appropriate particle distribution. Based on the
shape, the average particle size was about 20 nm.
Figures 4b and 4c, reveal the structure and morphol-
ogy of Ag/Cu2O NPs at different resolutions. As shown
in the figures, approximately 8% of the total area of Cu2O
is covered by silver. Average particle size is depicted
to be about 118 nm. This size points to the fact that the
photocatalyst is nanostructured. The morphology of the
synthesizedAg/Cu2O NPs was investigated with the help
of a transmission electron microscope (TEM) as shown
in Fig. 4d.
Figure 6 shows the Cu2O NPs hysteresis loop. If a pore
is formed by several parallel plates, a meniscus cannot be
formed as long as the vapour pressure of the adsorbate
is raised to the saturation vapor pressure. On desorption,
the pore is emptied at a relative pressure corresponding
to the extend of the capillary, as this will be the effective
radius of curvature of the meniscus. Thus, the isotherm
has an ascent adsorption branch at a relative pressure
of unity and a sloping desorption branch in between
relative pressures. Such an isotherm is said to show
type B hysteresis. Another type of capillary which may
cause to type B hysteresis is an ink-bottle pore with a
body, which is quiet wide, ca 1000 Å, that the adsorption
Elemental analysis. The EDXA technique was used
for elemental analysis and evaluation of the surface layers
of the Ag/Cu2O NPs. As indicated by the pattern shown
in Fig. 5, there are Ag and Cu elements with 37.79 and
11.56% w/w in the structure ofAg/Cu2O NPs, respectively.
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SEPAHVAND et al.
2011, vol. 519, no. 15, pp. 5169–5173.
branch practically coincides with a relative pressure of
unity [39].
11. Bender, M., Seeling, W., Daube, C., et al., J. Stollenwerk,
Thin Solid Films, 1998, vol. 326, nos. 1–2, pp. 67–71.
CONCLUSIONS
12. Yu, Y., D, F., Yu, J.C., et al., J. Solid State Chem., 2004,
In summary, Cu2O andAg/Cu2O NPs were synthesized
by the coprecipitation method. Ag/Cu2O NPs were
obtained by reducing Cu(OH)2 with ascorbic acid in
the presence of Ag three-dimensional crystals. The
results showed that doping of Ag in Cu2O increased
and upgraded the photocatalytic properties, so that the
degradation efficiency under optimal conditions (when
intensity is 32 W for 30 minutes) was calculated for Cu2O
Micro-Ps and NPs to be 20.0% and 91.4% respectively,
and for Ag/Cu2O and TiO2 NPs about 99.9%.
vol. 177, no. 12, pp. 4640–4647.
13. Lu, C.H., Qi, L.M., Yang, J.H., et al., Adv. Mater., 2005,
vol. 17, pp. 2562–2567.
14. Figueiredo, V., Elangovan, E., Goncalves, G., et al., J. Phys.
Status Solidi A, 2009, vol. 206, no. 9, pp. 2143–2148.
15. Wang, W.Z., Wang, G.H., Wang, X.S., et al., J. Adv. Mater.,
2002, vol. 14, no. 1, pp. 67–69.
16. Li, C.L. and Fu, Z.W., Electrochim. Acta, 2008, vol. 53,
no. 12, pp. 4293–4301.
The XRD analysis showed that the effects of doping
changed the crystal phase from cubic to hexagonal. This
means the creation of Ag/Cu2O NPs prevents the growth
of Cu2O NPs crystals.
17. Park, J.C., Kim, J., Kwon, H., and Song, H., Adv. Mater.,
2009, vol. 21, pp. 803–807.
18. Zhang, J., Liu, J., Peng, Q., et al., Chem. Mater., 2006,
vol. 18, no. 4, pp. 867–871.
The synthesis ofAg/Cu2O NPs is a suitable alternative
to TiO2 on an industrial scale due to functional simplicity,
cost-effectiveness, high efficiency and the limitations of
the synthesis method of TiO2 photocatalyst, including
its high cost.
19. Zhang, H., Zhu, Q., Zhang, Y., et al., Adv. Funct. Mater.,
2007, vol. 17, pp. 2766–2771.
20. Ma, L.L., Li, H.Z., Qiu, M.Q., et al., Mater. Res. Bull.,
2010, vol. 45, no. 8, pp. 961–968.
21. Fernando, C.A.N., Bandara, T.M.W.J., and Wetha-
singha, S.K., Sol. Energ. Mater. Sol. C, 2001, vol. 70, no. 2,
pp. 121–129.
REFERENCES
1. Elmi Fard, N., Fazaeli, R., and Ghiasi, R., J. Chem. Eng.
Tech., 2016, vol. 39, no. 1, pp.149–157.
22. Senevirathna, M.K.I., Pitigala, P.K.D.D.P., Tennakone, K.,
J. Photochem. Photobiol. A: Chem., 2005, vol. 171, no. 3,
pp. 257–259.
2. Kianfar,A.H. and Dostani, M., Russ. J. Appl. Chem., 2017,
vol. 28, no. 10, pp. 7353–7359.
23. Chang, Y., Teo, J.J., and Zeng, H.C., Langmuir, 2005,
vol. 21, no. 3, pp. 1074–1079.
3. Wang, Q., Li, J., Bai, Y., et al., J. Photochem. Photobiol.,
2013, vol. 126, pp. 47–54.
24. Chao, Q., Li, Z., Hui, W., and Jiang, C., J. Phys. Chem.
Lett., 2012, vol. 3, no. 5, pp. 651–657.
4. Basha, C.A., Sendhil, J., Selvakumar, K.V., et al., Desalin.,
2012, vol. 285, pp. 188–197.
25. Liu, H., Ni, Y., Wang, F., et al., Colloids Surf. A, 2004,
vol. 235, no. 1–3, pp. 79–82.
5. Moussavi, G. and Mahmoudi, M., J. Hazard. Mater., 2009,
vol. 168, nos. 2–3, pp. 806–812.
26. Wang, W .Z., Wang, G.H., Wang, X.S., et al., Adv. Mater.,
2002, vol. 14, no. 1, pp. 67–69.
6. Zhang, L., Yan, F., Su, M., et al., Russ. J. Inorg. Chem.,
2009, vol. 54, no. 8, pp. 1210–1216.
27. Wang, Z., Chen, X., Liu, J., et al., Room, Solid State
Commun., 2004, vol. 130, no. 9, pp. 585–589.
7. Liang, Sh., Zhou, Y., Wu, W., and Zheng, Y., J. Photochem.
Photobiol. A: Chemistry, 2017, vol. 346, pp. 168–176.
28. Xu, H. and Wang, W., Angew. Chem. Int. Ed., 2007, vol. 46,
no. 9, pp. 1489–1492.
8. Fujishima, A., Rao, T.N., and Tryk, D.A., J. Photochem.
Photobiol. C: Photochemistry Reviews, 2000, vol. 1, no. 1,
pp. 1–21.
29. Ma, L.L. , Li, J.L., Sun, H.Z., et al., Mater. Res. Bull., 2010,
vol. 45, no. 8, pp. 961–968.
9. Fujishima, A., Zhang, X., and Tryk, D. A., Surf. Sci. Rep.,
30. Wang, Z., Wang, H., Wang, L., and Pan, L., J. Phys. Chem.
Solids, 2009, vol. 70, no. 3–4, pp. 719–722.
2008, vol. 63, p. 515.
10. Tseng, C.C., Hsieh, J.H., and Wu, W., Thin Solid Films,
31. Deo, M., Shinde, D., Yengantiwar, A., et al., J. Mater.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 92 No. 1 2019

ENHANCING PHOTOCATALYTIC ACTIVITY OF Cu2O
149
Chem., 2012, vol. 22, no. 33, pp. 17055–17062.
36. Yadolah, D., The Concise Encyclopedia of Statistics,
Springer, 2008.
32. Reda, S.M., Khairy, M., and Mousa, M.A., Arabian J.
Chem., 2017, vol. 1, pp. 1–36.
37. Ghayyem, M.A., Keyhani, M., Behjoomanesh, M., and
Tavakoli, R., Conference and Exhibition, Kuala Lumpur,
05 May 2012.
33. Tao, Sh., Yanga, M., Chena, H., et al., J. Colloid Interface
Sci., 2017, vol. 486, pp. 16–26.
38. Sohrabi, S., Akhlaghian, F., Process Safety and Environ-
mental Protection, 2016, vol. 99, pp. 120.
34. Hu, X., Zhou, X., Wang, R., et al., Appl. Catal. B:
Environmental, 2014, vol. 154–155, p. 44.
39. Thomas, H., Salzberg, W., and Thomas, W.J., Academic
Press, London, 1967.
35. Yang, J., Li, Zhen, Zhao, C., et al., Mater. Res. Bull., 2014,
vol. 60, pp. 530–536.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 92 No. 1 2019