Synthesis, Structure, and Photocatalytic Activity of TiO₂-Montmorillonite Composites

Round 1

Reviewer 1 Report

Authors reported Synthesis, structure, and photocatalytic activity of TiO2-mont- 2 morillonite composites. The paper is well written and contains relevant discussion. This paper can be accepted in Catalysts after addressing the queries below:

1- Please add more quantitative data on photocatalytic MB degradation in abstract.
2- Figure 5b.related size 206 distribution of TiO2 particles: The histograms at 60-70 nm and above should be removed as they do not influence the median of the curve and crystallite size.

3- High quality Figure 11 should be provided.

4- It would be better (if possible) for the improvement of the paper if the authors can add the PL analyses and active species trapping (scavengers) and correlate it with the EPR experiments

Author Response

Point 1:Please add more quantitative data on photocatalytic MB degradation in abstract.

Response 1: The summary is modified as follows.

 In the present study, TiO₂–montmorillonite (MMT) composites were synthesized hydrothermally under variable conditions, such as TiO₂/MMT mass ratio, reaction pH, reaction temperature, and dwelling time. These samples were determined by X-ray photoelectron spectrometer (XPS), ultraviolet-visible spectroscopy (UV-Vis DRS), spectroscopy, electrochemical impedance spectroscopy (EIS), transient photocurrent responses, photoluminescence spectra (PL), Electron Paramagnetic Resonance (EPR), and N₂ adsorption-desorption isotherms. The photocatalytic activity was evaluated as the ability to promote the visible-light-driven degradation of 30 mg/L aqueous methylene blue, which was maximized for the composite with a TiO₂ mass ratio of 30 wt% prepared at a pH of 6, reaction temperature of 160 °C, and dwelling time of 24 h (denoted as 30%-TM)，and achieved a methylene blue removal efficiency of 95.6% which was 4.9times higher than that pure TiO₂. The unit cell volume and crystallite size of 30%-TM were 92.43 ų and 9.28 nm, respectively, with a relatively uniform distribution of TiO₂ particles on the MMT surface. In addition, 30%-TM had large specific surface area, strong light absorption capacity and high Ti³⁺ content among the studied catalysts. Thus, the present study provides a basis for the synthesis of composites with controlled structure.

Point 2:Figure 5b.related size 206 distribution of TiO₂ particles: The histograms at 60-70 nm and above should be removed as they do not influence the median of the curve and crystallite size.

Response 2:

The modification in figure 5b is as follows.

Figure 5. (a) Representative scanning electron microscopy image of 30%-TM and (b) related size distribution of TiO₂ particles.

Point 3:High quality Figure 11 should be provided.

Response 3:

The modification in figure 11 is as follows.

Figure 11. (a) Nitrogen adsorption/desorption isotherms of TiO₂, 30%-TM and (b) pore size distribution of TiO₂ , 30%-TM.

Point 4: It would be better (if possible) for the improvement of the paper if the authors can add the PL analyses and active species trapping (scavengers) and correlate it with the EPR experiments.

Response4: The related experiments of trapping agents were added, and the experimental data and the discussion combined with PL and EPR are as follows.

Figure 17.Trapping experiment of active substances in photocatalytic degradation of TiO₂-MMT

Figure 11 shows the capture experiment of active substances in the process of MB degradation. In the degradation process, isopropanol (IPA), disodium ethylenediamine tetraacetate (EDTA-2Na) and p-benzoquinone (BQ) of 1mmol were added as scavengers of hydroxyl radical (·OH), hole (h⁺) and superoxide radical ( ·O₂⁻ ) respectively, to further explore the role of active substances in the process of photodegradation. It was obvious that the addition of IPA, EDTA-2Na and BQ affected the efficiency of photodegradation of pollutants, indicating that ·OH, h⁺ and ·O₂⁻ played an important role in the process of photodegradation, and the inhibitory effect of BQ is the most obvious. Therefore, ·O₂⁻ played a more important role in the process of photocatalytic degradation. This was consistent with the test results of EPR. As shown in figure 10, DMPO-·O₂⁻ had more obvious peaks in light conditions. In addition, combined with figure 14c, the recombination rate of the electron hole was lower, and the electron and hole functioned separately for a longer time, so it had better photocatalytic efficiency.

Author Response File: Author Response.pdf

Reviewer 2 Report

Minor Revision

catalysts-1687766

The submitted article “catalysts-1687766” comprises the study of TiO₂–montmorillonite (MMT) composites that were synthesized hydrothermally under variable conditions, such as TiO2/MMT mass ratio, reaction pH, reaction temperature, and dwelling time. The author mentioned TiO₂ particles on the MMT surface. In addition, 30%-TM had a large specific surface area, strong light absorption capacity, and high Ti³⁺ content among the studied catalysts and achieved a methylene blue removal efficiency of 95.6% after 2 h. Thus, the present study provides a basis for the synthesis of composites with a controlled structure.

However, apart from that, some points need to include and revise few sections of this article, and thus a minor revision is required.

Comments are as follows:

Reviewer comments

1. In the introduction section, the authors need to mention and cover the structural and morphological role of TiO₂ and compare it with another metal oxide.

            Hence, structural, morphological, utilization, and application should be highlighted in the introduction section of the manuscript. These novel references must be included and highlighted:

doi.org/10.2109/jcersj2.17235

doi.org/10.1038/s41598-018-19617-2

2. The introduction should be clarified in terms of uniqueness and the advantage of the novelty of this work over the previous related works.
3. Figure 1. is very simplistic, the authors need to include the chemical bonding between these two materials.
4. In figures 2 and 3, XRD, the plane numbers are blurred, the author needs to include a clear image and make it clearer.
5. Figure 4. SEM analysis, the author needs to give a clear explanation and give the different reasons in the text between a-d of figure 4.
6. Figure 11 is also not visible; the author needs to revise all the listed figures and make them visible to the readers.
7. Provide the full names for abbreviations when they appear for the first time in the text including "Abstract"
8. The author needs to write a critical discussion with state-of-the-art
   literature after the presentation and discussion of your results.
9. The author should completely check and revise the format of their manuscript according to the author guidelines of this journal.

Overall, the writing and included results seem reasonable except for the above-mentioned comments, the author needs to include all the suggestions and cite the given articles before acceptance.

Comments for author File: Comments.pdf

Author Response

Point 1:In the introduction section, the authors need to mention and cover the structural and morphological role of TiO₂ and compare it with another metal oxide.

            Hence, structural, morphological, utilization, and application should be highlighted in the introduction section of the manuscript. These novel references must be included and highlighted:

doi.org/10.2109/jcersj2.17235

doi.org/10.1038/s41598-018-19617-2

Response 1:References have been quoted, the specific contents are as follows.

Montmorillonite (MMT) is a common lamellar aluminosilicate [13] that is often used as a photocatalyst support owing to its large specific surface area [10], high adsorption capacity for cations and polar molecules [14], and stable chemical properties [15]. The composites of TiO₂–MMT have been reported to exhibit slower electron–hole recombination and promote better oxidative degradation of pollutants by ozone compared to pure TiO₂ and MMT [16]. The porosity of these composites, prepared by reacting titanium silicalite with titanium alkoxides at 50–80 °C, strongly influences their ability to adsorb dyes such as methylene blue (MB), which can be adjusted by varying the reaction temperature [17]. A study reporting the preparation of TiO₂ gel from Titanium tetrachloride (TiCl₄) at 30–80 °C demonstrated the photocatalytic performance of the resulting TiO₂–MMT composite, which was maximized at a reaction temperature of 70 °C [18]. In another study, TiO₂–MMT suspensions were hydrothermally prepared from Titanium sulfide (Ti(SO₄)₂) and MMT at pH 4 and calcined for 2 h at 300–1200 °C [10]. The growth of anatase and rutile TiO₂ was inhibited by adding MMT, while the complete transformation of anatase TiO₂ into rutile TiO₂ was observed at 900 °C. TiO₂–MMT composites prepared by combining cation filling, sol-gel processing, and thermal treatment featured a narrow band gap of 2.79 eV and advantageous structural properties [19]. Preparation of Carbon-modifified nitrogen-doped TiO₂/ montmorillonite composite by Sol-Gel method increased the absorption range of light and realized the effective separation of photogenerated electron pairs [1]. Mohammad et al prepared a kind of gray titanium dioxide, which increased the content of Ti³⁺ and oxygen vacancy in titanium dioxide and increased the rate of charge transfer [21]. Yusuke et al studied the synergistic effect of Layered Silicate and TiO₂ on photocatalytic oxidation of benzene to recover phenol with unprecedented efficiency and selectivity [22].

More recently, TiO₂–MMT composites were shown to exhibit high photocatalytic activity even at elevated temperatures, which was ascribed to the presence of TiO₂ in the anatase phase [16, 17, 23, 24]. Esmail et al reported a Cl-doped rutile titanium dioxide photocatalyst, which alone can produce lower effective carrier mass, higher photogenerated electron and hole mobility, and longer Ti³⁺ ion interaction lifetime, thus improving the photocatalytic activity[25]. Compared to pure TiO₂, TiO₂–MMT composites are easier to recover, facilitating their industrial applications [26], and can exhibit reduced absorbance at 220–300 nm [27]. Numerous studies have probed the effects of photodegradation conditions (such as solution pH, initial dye concentration, reaction atmosphere, and illumination time) on the photocatalytic performance of TiO₂–MMT composites [10, 16, 27-29].

However, only a few have examined the corresponding effects of composite preparation conditions, such as the TiO₂/MMT mass ratio and pH of the hydrothermal reaction, which may affect the structure and properties of the composite (for example, phase composition, chemical bonding, absorption range, and energy bands), thereby influencing the photocatalytic performance. Herein, we hydrothermally synthesized pure TiO₂ and TiO₂–MMT composites. We examined the effect of TiO₂ content, reaction pH, reaction temperature, and dwelling time on the ability of these composites to promote the photodegradation of MB, which was compared with those of pure TiO₂ and MMT. Through the detection and analysis of X-ray photoelectron spectrometer (XPS), ultraviolet-visible spectroscopy (UV), electrochemical impedance spectroscopy (EIS), transient photocurrent responses, photoluminescence spectra (PL), Electron Paramagnetic Resonance (EPR), Brunner-Emmet-Teller measurements (BET), the materials with the best properties under different conditions were explored. Thus, this study describes valuable correlations between synthetic conditions and catalyst properties and thus provides a basis for synthesizing composites with controlled structure.

Point 2: The introduction should be clarified in terms of uniqueness and the advantage of the novelty of this work over the previous related works.

Response 2: 

The following changes have been made at the end of the introduction of the article, which are as follows.

However, only a few have examined the corresponding effects of composite preparation conditions, such as the TiO₂/MMT mass ratio and pH of the hydrothermal reaction, which may affect the structure and properties of the composite (for example, phase composition, chemical bonding, absorption range, and energy bands), thereby influencing the photocatalytic performance. Therefore, this word explored the effects of different preparation conditions on the properties of the composites, and explored the composites with the best properties.Herein, we hydrothermally synthesized pure TiO₂ and TiO₂–MMT composites. We examined the effect of TiO₂ content, reaction pH, reaction temperature, and dwelling time on the ability of these composites to promote the photodegradation of MB, which was compared with those of pure TiO₂ and MMT. Through the detection and analysis of X-ray photoelectron spectrometer (XPS), ultraviolet-visible spectroscopy (UV), electrochemical impedance spectroscopy (EIS), transient photocurrent responses, photoluminescence spectra (PL), Electron Paramagnetic Resonance (EPR), Brunner-Emmet-Teller measurements (BET), the materials with the best properties under different conditions were explored. Thus, this study describes valuable correlations between synthetic conditions and catalyst properties and thus provides a basis for synthesizing composites with controlled structure.

Point 3: Figure 1. is very simplistic, the authors need to include the chemical bonding between these two materials.

Response 3: The modified figure1 is as follows.

Figure 1. Schematic synthesis of TiO₂-MMT TiO₂–montmorillonite (MMT) composites.

Point 4: In figures 2 and 3, XRD, the plane numbers are blurred, the author needs to

include a clear image and make it clearer.

Response 4:

The modified figures 2 and 3 are as follows.

Figure 2. X-ray diffraction patterns of TiO₂–montmorillonite (MMT) composites prepared using different (a) TiO₂/MMT mass ratios at a reaction temperature of 160 ℃, dwelling time of 24 h, and pH of 6 and (b) pH at a reaction temperature of 160 ℃, dwelling time of 24 h, and TiO₂ mass ratio of 30 wt%.

Figure 3. X-ray diffraction patterns of TiO₂–montmorillonite (MMT) composites prepared using different (a) reaction temperatures at a dwelling time of 24 h, a pH of 6, and a TiO₂ mass ratio of 30 wt% and (b) dwelling times at a reaction temperature of 160 ℃, a pH of 6, and a TiO₂ mass ratio of 30 wt%.

Point 5: Figure 4. SEM analysis, the author needs to give a clear explanation and give the different reasons in the text between a-d of figure 4.

Response 5: 

Fig. 4. (a–d) Scanning electron microscopy images of 30%-TM at different magnifications.

Figure 4 shows the SEM images of 30%-TM at different magnifications, revealing that the ordered lamellar structure of MMT remains intact after the hydrothermal reaction and showing the presence of well-dispersed TiO₂ nanoparticles on and between the MMT layers.
Fig. 4b is a locally enlarged image within the green frame line of fig. 4a. Figs. 4c and 4d are enlarged views of the local areas of figs. 4b and 4c, respectively. In figure 4d, the gap between the titanium dioxide particles and the lamellar structure of montmorillonite is clearly visible.

Point 6:Figure 11 is also not visible; the author needs to revise all the listed figures and make them visible to the readers.

Response 6: 

The modification in figure 11 is as follows.

Figure 11. (a) Nitrogen adsorption/desorption isotherms of TiO₂, 30%-TM and (b) pore size distribution of TiO₂ , 30%-TM.

Point 7:Provide the full names for abbreviations when they appear for the first time in the text including "Abstract"

Response 7: The revised words include Titanium tetrachloride (TiCl₄), Titanium sulfide (Ti(SO₄)₂), all of which have been revised in the article.The other words that appear for the first time are all the spellings of the word.

Point 8:The author needs to write a critical discussion with state-of-the-art literature after the presentation and discussion of your results.

Response 8: The discussion is held at the end of the section, which is as follows.

The study of the structure, morphology and chemical bond, proved that the layered structure of montmorillonite was still intact and Si-O-Ti was successfully formed. Tao et  pointed out in their research that Si-O-Ti could increase Ti³⁺ content and oxygen vacancy in the composites [19]. In this work, the Ti³⁺/Ti⁴⁺ contentwas determined and simulated, and increased by 20.81%. In addition, from the optical absorption, electron and hole recombination efficiency, photogenerated carrier behavior and specific surface area, proved that 30%-TM had strong optical absorption capacity, low electron hole recombination efficiency, large specific surface area and high Ti³⁺ content. This work also explored the role of active substances in the degradation process, which fully proved the significant role of ·OH, h⁺ and ·O₂⁻, especially the degradation efficiency of ·OH. In a recent study, Thi et al studied the efficiency and mechanism of photocatalytic degradation of MMT / TiO₂-nanotubes [28]. Ami’s group prepared titanium dioxide composite clay photocatalyst by microwave hydrothermal (5 min) and calcination method, which proved that TiO₂ / bentonite photocatalyst has high photocatalytic efficiency [63]. However, in most research works the preparation conditions were single exploration, and the exploration of different preparation conditions. This study will play a guiding role in the compounding of clay and titanium dioxide.

Point 9:The author should completely check and revise the format of their manuscript according to the author guidelines of this journal.

Response 9: The article has been revised as required, and the revised draft has been sent to the editor.

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors have synthesized the TiO₂ in montmorillonite and used it as a photocatalytic application. However, the XRD shows that the major fraction of montmorillonite has converted into quartz during the calcination or catalyst preparation. Moreover, silica-based structures act as insulators and are not suitable for charge separation applications. I would be curious to know what was the main reason for using such support for titania. However, there are some recent report that uses layered silicate to trap the degradation agent and to degrade more efficiently. See the following paper: J. Am. Chem. Soc. 2013, 135, 32, 11784–11786. Furthermore, The introduction needs a more profound discussion/citation about the recent advances of titania; for instance: Applied Catalysis B: Environmental, 2021, 297, 120380.

Where the authors have obtained the lattice parameters from? is it from calculation or from the literature. If it is from literature, then it is not accurate and should be calculated. 

It is better to show the HRTEM images to see how three different structures are spread in the composite. 

The suggested mechanism for the photodegradation of MB through MM-TiO₂ sounds not accurate. what is the main proof to show that the MM can separate the electrons? Moreover, there is quartz as well in the structure that is overlooked. 

Author Response

Point 1:The authors have synthesized the TiO₂ in montmorillonite and used it as a photocatalytic application. However, the XRD shows that the major fraction of montmorillonite has converted into quartz during the calcination or catalyst preparation. Moreover, silica-based structures act as insulators and are not suitable for charge separation applications. I would be curious to know what was the main reason for using such support for titania. However, there are some recent report that uses layered silicate to trap the degradation agent and to degrade more efficiently. See the following paper: J. Am. Chem. Soc. 2013, 135, 32, 11784–11786. Furthermore, The introduction needs a more profound discussion/citation about the recent advances of titania; for instance: Applied Catalysis B: Environmental, 2021, 297, 120380.

Response 1:

Fig. 1. X-ray diffraction patterns of montmorillonite (MMT)

Figure 1 shows the XRD diffraction peak of montmorillonite, it is obvious that there is quartz in the raw material of montmorillonite, and quartz is not formed in the preparation process. In addition, quartz accounts for about 64% of the montmorillonite in XRF analysis.

The molecular formula of montmorillonite is (0.5Ca,Na)_0.66(Al,Mg,Fe)₄[(Si,Al)₈O₂₀] (OH)₄·nH₂O. Common montmorillonite contains Ca and Na. After treatment, it may contain metal elements such as K, Cs, Sr, Mg, Fe. There are more cations in montmorillonite, among which the cations with high electricity price have higher ion exchange capacity, so their adsorption capacity is stronger, and indirectly increase the degradation ability of the composites. In addition, montmorillonite can provide more adsorption sites, which can not only provide loading sites for TiO₂, but also effectively increase the specific surface area of the composites, and provide favorable conditions for the recovery and reuse of catalytic materials.  In the presence of MMT, the generated electrons move to the empty d-orbital of the metals in MMT structure. This electron transfer process can prevent the e⁻- h⁺ pair from recombination. Then, electrons trapped in MMT react with O₂ to produce free superoxide radicals (●O²⁻ ). With the increase of active substances(·O₂⁻,e⁻, h⁺, ·OH), the photocatalytic efficiency is further increased. Thi et al also reported that montmorillonite reduced the recombination of electrons and holes[1]. These are the main reasons for choosing composite montmorillonite.

[1] T.B.T. Dao, T.T.L. Ha, T.D. Nguyen, H.N. Le, C.N. Ha-Thuc, T.M.L. Nguyen, P. Perre, D.M. Nguyen, Effectiveness of photocatalysis of MMT-supported TiO₂ and TiO₂ nanotubes for rhodamine B degradation, Chemosphere, 280 (2021) 130802.

Then, I revised part of the introduction and quoted the above two articles（J. Am. Chem. Soc. 2013, 135, 32, 11784–11786）（Applied Catalysis B: Environmental, 2021, 297, 120380）. The introduction was revised as follows.

Montmorillonite (MMT) is a common lamellar aluminosilicate [13] that is often used as a photocatalyst support owing to its large specific surface area [10], high adsorption capacity for cations and polar molecules [14], and stable chemical properties [15]. The composites of TiO₂–MMT have been reported to exhibit slower electron–hole recombination and promote better oxidative degradation of pollutants by ozone compared to pure TiO₂ and MMT [16]. The porosity of these composites, prepared by reacting titanium silicalite with titanium alkoxides at 50–80 °C, strongly influences their ability to adsorb dyes such as methylene blue (MB), which can be adjusted by varying the reaction temperature [17]. A study reporting the preparation of TiO₂ gel from Titanium tetrachloride (TiCl₄) at 30–80 °C demonstrated the photocatalytic performance of the resulting TiO₂–MMT composite, which was maximized at a reaction temperature of 70 °C [18]. In another study, TiO₂–MMT suspensions were hydrothermally prepared from Titanium sulfide (Ti(SO₄)₂) and MMT at pH 4 and calcined for 2 h at 300–1200 °C [10]. The growth of anatase and rutile TiO₂ was inhibited by adding MMT, while the complete transformation of anatase TiO₂ into rutile TiO₂ was observed at 900 °C. TiO₂–MMT composites prepared by combining cation filling, sol-gel processing, and thermal treatment featured a narrow band gap of 2.79 eV and advantageous structural properties [19]. Preparation of Carbon-modifified nitrogen-doped TiO₂/ montmorillonite composite by Sol-Gel method increased the absorption range of light and realized the effective separation of photogenerated electron pairs [1]. Mohammad et al prepared a kind of gray titanium dioxide, which increased the content of Ti³⁺ and oxygen vacancy in titanium dioxide and increased the rate of charge transfer [21]. Yusuke et al studied the synergistic effect of Layered Silicate and TiO₂ on photocatalytic oxidation of benzene to recover phenol with unprecedented efficiency and selectivity [22].

More recently, TiO₂–MMT composites were shown to exhibit high photocatalytic activity even at elevated temperatures, which was ascribed to the presence of TiO₂ in the anatase phase [16, 17, 23, 24]. Esmail et al reported a Cl-doped rutile titanium dioxide photocatalyst, which alone can produce lower effective carrier mass, higher photogenerated electron and hole mobility, and longer Ti³⁺ ion interaction lifetime, thus improving the photocatalytic activity[25]. Compared to pure TiO₂, TiO₂–MMT composites are easier to recover, facilitating their industrial applications [26], and can exhibit reduced absorbance at 220–300 nm [27]. Numerous studies have probed the effects of photodegradation conditions (such as solution pH, initial dye concentration, reaction atmosphere, and illumination time) on the photocatalytic performance of TiO₂–MMT composites [10, 16, 27-29].

Point 2:Where the authors have obtained the lattice parameters from? is it from calculation or from the literature. If it is from literature, then it is not accurate and should be calculated.

Response 2:

The lattice parameters are all calculated, and the a, b, c are measured by X-ray diffraction (XRD; Bruker D8 ADVANCE). The cell volume and crystal size can be calculated. the unit cell parameters, unit cell volumes (V), and crystallite sizes (D) of the investigated materials, belonging to the tetragonal system. The unit cell volume was calculated as V = 0.866a²c, and the crystallite size was calculated as D = Kλ/(βcosθ), where θ is the diffraction angle, β is the full width at half-maximum of the most intense peak, λ is the X-ray wavelength (0.15406 nm), and K is the Debye–Scherrer constant (0.89) .

Point 3:It is better to show the HRTEM images to see how three different structures are spread in the composite.

Response 3:

Fig.2.(a-c) transmission electron microscope images of 30%-TM at different magnifications.

Figure 2 shows the TEM picture of 30%-TM. Figures b and c are enlarged pictures of different positions in figure a. The inset of Fig.3c shows the SAED pattern of area in red circle. The fringes across images of nanocrystal in red circle have a periodicity of 0.35 nm which well matched the d-spacing of (101) planes of Anatase TiO2 according to JCPDS NO.73-1764. In figures a and b, the small black particles represent titanium dioxide particles, which were attached to the surface of montmorillonite and distributed on the surface and interlayer of montmorillonite. Quartz was a part of the lamellar structure of montmorillonite, in the lamellar structure of montmorillonite.

Point 4:The suggested mechanism for the photodegradation of MB through MMT-TiO₂ sounds not accurate. what is the main proof to show that the MM can separate the electrons? Moreover, there is quartz as well in the structure that is overlooked.

Response 4:

The molecular formula of montmorillonite is (0.5Ca,Na)_0.66(Al,Mg,Fe)₄[(Si,Al)₈O₂₀] (OH)₄·nH₂O. Common montmorillonite contains Ca and Na. After treatment, it may contain metal elements such as K, Cs, Sr, Mg, Fe.  In the presence of MMT, the generated electrons move to the empty d-orbital of the metals in MMT structure. This electron transfer process can prevent the e⁻- h⁺ pair from recombination. Then, electrons trapped in MMT react with O₂ to produce free superoxide radicals (●O²⁻ ). With the increase of active substances(·O₂⁻,e⁻, h⁺, ·OH), the photocatalytic efficiency is further increased. Thi et al also reported that montmorillonite reduced the recombination of electrons and holes[1]. 

[1] T.B.T. Dao, T.T.L. Ha, T.D. Nguyen, H.N. Le, C.N. Ha-Thuc, T.M.L. Nguyen, P. Perre, D.M. Nguyen, Effectiveness of photocatalysis of MMT-supported TiO₂ and TiO₂ nanotubes for rhodamine B degradation, Chemosphere, 280 (2021) 130802.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors have revised the manuscript accordingly, however, before final publication, in the introduction, the authors should make sure that the authors are mentioned in the introduction with their surnames not first names.