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Article

Investigating the Photocatalytic Properties of Reduced Graphene Oxide-Coated Zirconium Dioxide and Their Impact on Structural and Morphological Features

by
Norhan Farghly
1,
M. Abu El-Oyoun
1,
A. Abousehly
1,
Fatemah H. Alkallas
2,
Amira Ben Gouider Trabelsi
2,
E. R. Shaaban
3 and
Abdelaziz Mohamed Aboraia
3,*
1
Physics Department, Faculty of Science, Assiut University, Assiut 7115, Egypt
2
Department of Physics, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
3
Department of Physics, Faculty of Science, Al-Azhar University, Assiut 71524, Egypt
*
Author to whom correspondence should be addressed.
Catalysts 2025, 15(3), 289; https://doi.org/10.3390/catal15030289
Submission received: 29 January 2025 / Revised: 28 February 2025 / Accepted: 14 March 2025 / Published: 19 March 2025
(This article belongs to the Special Issue Design and Application of Combined Catalysis)
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Abstract

Semiconductor photocatalytic technology demonstrates strong potential as a solution to defend environmental systems while converting energy. The photocatalytic behavior of traditional ZrO2 catalysts suffers a major disadvantage because their activity remains low in visible light applications. XRD together with SEM, as well as EDX and EIS techniques, were utilized to evaluate the synthetic materials. This study demonstrated that the development of RGO-modified ZrO2 heterostructures delivered substantial increases in photocatalytic functionality through effective photogenerated charge separation mechanisms. Tests showed the RGO/ZrO2 heterostructures exhibited outstanding photocatalytic behavior that led to an 80% MB solution breakdown in 120 min while exceeding electrocatalytic parameters in multiple tests. The experimental data from UV–vis spectroscopy combined with electrochemical analysis and radical trapping methods demonstrated that heterostructure improvement resulted from higher light absorption rates and effective active site exposure while providing better electron/hole pair separation. This research establishes S-scheme heterostructures to enable advancements in environmental protection alongside energy conversion technologies.

1. Introduction

Recently, ecologists have focused their attention on water-soluble and volatile compounds, especially dyes [1,2]. Wastes from the dye and textile industries are very harmful to aquatic life [3,4]. These residues represent a substantial danger to human health and can cause cancer. The release of dyes into bodies of water is the primary cause of eutrophication, the contamination of water, and aquatic ecosystem disruption [5,6]. Extensive efforts in the last few years to tackle these environmental issues have focused mostly on the photocatalytic process as the best method for successful dye repair in the presence of light [7,8]. The study of photocatalytic techniques is closely linked to the examination of materials used in photocatalysis. ZrO2 is a transition metal oxide that is environmentally friendly, as it has low toxicity and is chemically stable [9,10]. Furthermore, it is biobased, inexpensive, and exhibits outstanding thermal stability as well as electrochemical characteristics [11,12]. Because of its exceptional electrocatalytic characteristics, It works well as an active electrode material in crucial electrocatalytic investigations [13,14]. Currently, semiconductor elements, such as ZnO, TiO2, and ZrO2, are now the most common materials utilized in photocatalysts, serving as the catalyst’s primary component [15,16,17]. Among these, ZrO2 is known as the only metal having oxidizing and reducing properties due to its acidic nature and properties [18].
Since ZrO2 is sorted as a semiconductor with the p-type, it readily generates oxygen holes, which can carry excitation and promote the interaction between active layers [19,20,21]. Consequently, it shows improved viability as a photocatalyst when contrasted with elective materials [9,22]. The zirconia experiences difficulties when utilized as an independent semiconductor, for example, a high pace of transporter recombination and diminished quantum proficiency, which to some degree limits its down-to-earth utility [23,24]. The broadband hole limitation of zirconia materials restricts their ability to absorb UV radiation while blocking out nearly 96% of sunlight across the spectrum. Thus, its far-reaching application is restricted [23,25]. Currently, numerous research studies center on improving the photocatalytic effectiveness of zirconia through various techniques, including doping, incorporating carbon nanotubes, and employing several other methods [26,27]. Researchers have found the last method to be the most effective, resulting in the creation of composites by various scientists in order to enhance their photocatalytic activity in visible light [28,29,30]. Previous studies have shown that when exposed to UV light, ZrO2 can effectively break down textile dyes, for instance, rhodamine B, reactive yellow, and 2,2,4-diphenoxyacetic through a process known as photodegradation [31]. The improved reactivity observed in the UV light in the previous examples can be attributed to two factors, either the catalyst’s stability or an enlargement of the surface area. Another contributing factor is the charge transfer process facilitated by ZrO2, which benefits from its small particle size, large surface area, and a large number of surface hydroxyl (OH) groups. In recent times, there has been significant emphasis from researchers on enhancing the photocatalytic capabilities of carbon-based nanocomposites [32]. As a result, graphene, an exceptionally appealing component, was specially chosen for the production of these composites [33]. This is attributed to its large specific surface area and a two-dimensional p-p conjugation structure with outstanding electron conductivity [34]. Previous research has examined the characteristics of transporters in pure graphene layers, revealing that they exhibit similarities to massless Dirac fermions. As an example, when TiO2 nanocrystals are mixed with graphene, electrons from the band of conduction (CB) that are stimulated by TiO2 can transfer to go by means of a percolation procedure [35]. The Schottky barrier is a heterojunction generated at the interface that effectively distinguishes photo-induced electron–hole pairs, limiting charge recombination [36]. Several techniques have been used to produce RGO; in our investigation, the RGO is produced using waste bottle plastics. ZrO2 was covered with RGO using an affordable and efficient process. The morphological and structural qualities were examined. For the first time, electrocatalysis and photocatalysis were investigated in ZrO2@%RGO.

2. Result and Discussion

Figure 1 displays the XRD patterns of pure ZrO2 and ZrO2 covered with various RGO concentrations. It was found by X’pert HighScore search–match analysis that the tetragonal phase of ZrO2 “(P 42/n m c:1) is present. The widening of peaks observed in all the patterns indicates that the powders synthesized have a noncrystalline structure. Coated samples indicate that RGO has an amorphous phase compared to the pure sample. Moreover, the distinct and sharp diffraction peaks clearly support the successful synthesis to pure ZrO2 tetragonal through calcination. Furthermore, for the remaining groups, significantly different peaks were recorded at “28.2°, 31.5°, 34.1°, 35.3°, and 50.1°, which can be directly attributable to the tetragonal ZrO2”.
SEM images observed from pure ZrO2 and covered with varying percentages of RGO nanocomposites are shown in Figure 2. The pure ZrO2 demonstrates a surface that is smooth and does not have any additional substances added to it, as demonstrated in Figure 2a. However, Figure 2b,c shows SEM images of the RGO-ZrO2 nanocomposite, which demonstrates the formation of a several-layer structure made up of RGO sheets. Furthermore, larger accumulated ZrO2 particles were seen on the surface of the RGO sheets. The created ZrO2 has an irregular shape, with particle sizes less than 100 nm. This combination results from heterogeneous solid nucleation among RGO and ZrO2. Figure 3a shows the results of EDAX analysis, which was used to determine the elements present in the nanocomposite. EDAX data analysis “showed Zr, C, and O contents of 64, 25.2, and 10.0%”, correspondingly. The elements C, O, and Zr, in this distribution, grant confirmation for the formation of RGO-ZrO2 nanocomposites. When a single layer of RGO is combined with a metal oxide to form a nanocomposite, a multilayer structure is formed. Additionally, due to the limitations of SEM, it can also be viewed as multidimensional.
The band gap “Eg” that characterizes the electronic configuration of both pristine ZrO2 and covered ZrO2 with various amounts of RGO is determined by the lowest possible energy transfer between their valence and conduction bands. The metal oxide nanoparticles triggered the production of reactive oxygen species (ROS) in the photocatalysis mechanism. The creation of ROS—such as ·OH− and O2 that occur using ZrO2-coated ZrO2 with different concentrations of RGO materials—depends on the energy band gap and redox potential of the variations among reactive species. The energy band gap (Eg) value is extracted from the extrapolation of the linear section of a plot of (α.hν)2 vs. photon energy (eV), as presented in Figure 4. “The energy band gap (Eg) values for ZrO2 nanoparticles and ZrO2 coated with different concentrations of RGO nanocomposites were decreased from 5.6 and 3.9 eV, respectively. The energy band gap value obtained for ZrO2/RGO closely matched the value reported by Braj Raj Singh and colleagues [37].” Compared to ZrO2, ZrO2/RGO has a lower energy band and displays a higher electronic surface area, indicating its potential as a photoconductor that is more active when exposed to sunlight. The low surface area of ZrO2/RGO is due to its good crystallinity and lack of oxygen vacancies. One possible explanation for the band gap lowering is the chemical bonding among ZrO2 and certain carbon sites through the production method. When ZrO2 was placed on the prepared RGO sheets, the Eg value decreased to 3.86 eV, showing that ZrO2@%RGO can absorb visible light. The decrease in band ratio can be ascribed to the Zr-C and Zr-O-C bonds among ZrO2 and RGO. These results indicate that ZrO2@%RGO nanocomposites “NCs” have good photocatalytic activity.
The flat band potential of each semiconductor was determined using Mott–Schottky analysis as described in Supplementary Information. The electrical band structures of pure ZrO2 and ZrO2@%RGO were investigated and shown in Figure 5a–d. Based on the plot features, it is possible to conclude that the positive slope found in both pure ZrO2 and ZrO2@%RGO indicates the presence of n-type behavior. The Mott–Schottky performance of all semiconductor devices was analyzed at a frequency of 500 Hz. “As-synthesized photocatalysts’ flat band potential is 0.17, 0.20, 0.53, and 0.29 eV vs. SCE for ZrO2 and coated with different concentrations of 0.01, 0.03, and 0.04 RGO, correspondingly.”
The effectiveness of photogenerated exciton separation and the resistance of the interface layer in pristine ZrO2 and ZrO2@%RGO photocatalysts was evaluated utilizing EIS, as depicted in Figure 6, depicting the electrolyte system due to the electrolyte and electronic resistance of the photoelectrodes. The low-frequency portion pertains to the Warburg resistance. It is noted that ZrO2@4% RGO is smaller compared to pure ZrO2 and other photocatalysts, suggesting its effective interfacial charge separation and superior conductivity characteristics. The high electrical conductivity facilitates electron flow at the electrode–electrolyte solution interface. The preceding analysis confirms the crucial contribution of ZrO2 in the composite to prolong the lifespan of photoinduced charge carriers.

Photocatalytic Performance

The study of the optical characteristics of a photocatalyst is largely defined by the ability to promote the absorption of UV-Vis light. There is no significant change in the dye degradation without a catalyst as, demonstrated in Figure S2. UV-Vis absorption spectra of ZrO2 nanoparticles (NM) and ZrO2@%RGO composites are given in Figure 7a–d. The photocatalytic activity of synthesized ZrO2 and ZrO2@%RGO was analyzed by checking the decolorization of methylene blue (MB) dye solution exposed to 120 min of sunlight. The results showed that the ZrO2@%RGO sample had higher photocatalytic activity than ZrO2 because of the better sunlight absorption and fewer electron–hole recombination rates in the metal oxides due to the incorporation of reduced graphene oxide. The photocatalytic tests were conducted after the dye molecules were absorbed into the composite material to the greatest extent. When this concentration was associated with light, minimal degradation for the dye was recorded when the solution was in the dark. Likewise, the percentage of MB changed very little when the sample was put under sunlight in the absence of the photocatalyst. In the final 120 min after the samples had been exposed to sunlight, there was negligible photolysis of the dye. The degradation efficiencies of MB for ZrO2 and ZrO2@%RGO are demonstrated at Figure 8a under sunlight irradiation of 65% and 80%, respectively. In Figure 8b, the photocatalytic decomposition of MB between ZrO2 and ZrO2@%RGO under sunlight irradiation was compared. “Furthermore, the degradation kinetics of MB have been modelled and plotted based on the principles of pseudo-first-order kinetics theory (ln (C0/Ct)) = kt, where k represents the apparent first-order rate constant, as shown in Figure 8b.” It may be shown that the rate constants for ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO are 0.00886, 0.00975, 0.00999, and 0.0119 min−1, respectively. The ZrO2@4%RGO sample exhibits the greatest k value, which is around twice as large as that of ZrO2.
Light exposure failed to initiate significant dye breakdown in the observations. Methylene blue (MB) showed a minimal photolysis reaction in the absence of a photocatalyst under sunlight exposure which lasted up to 120 min. Figure 9a displays MB degradation levels at 65% with ZrO2 and 80% with ZrO2/rGO composite under sunlight irradiation. The light stability of these photocatalysts was assessed through recurring tests under sunlight irradiation, as shown in Figure 9b. For ZrO2@4%rGO, the recycling test was performed over four cycles using the same sample with a fresh dose of dye introduced for degradation in each cycle. Between cycles, the samples were washed and dried prior to the next run. Over the first three cycles, the degradation percentage remained consistent; however, after the fourth cycle, there was a decrease in degradation efficiency, likely due to sample loss during washing. This confirms that ZrO2@4%rGO exhibits excellent recycling efficiency and maintains stability throughout the process. Table 1 shows a comparative evaluation of ZrO2 structures that degrade MB dye through photocatalysis.
The process of photodegradation for MB dye on the surface of a photocatalyst entails the creation of electron–hole pairs. To enhance the photocatalytic activity of the ZrO2/RGO photocatalyst, it needs to absorb photons from UV-Vis light irradiation. The energy absorbed by the photocatalyst should be equal to or greater than its band gap energy. Consequently, this results in the excitation of electrons moving from the valence band (VB) to the conduction band (CB), leaving behind holes in the VB and generating electrons in the CB. The conduction band (CB) edge level of ZrO2 is higher than the Fermi energy of RGO, causing excited photoelectrons to transfer from the CB of ZrO2 to the surface of RGO. This movement of electrons helps RGO reduce the recombination rate of photoinduced charge carriers and prolongs the lifetime of the electron–hole pairs. As a result, RGO significantly enhances the photocatalytic activity of ZrO2. The electrons transferred to rGO can then be captured by dissolved O2 molecules, forming superoxide radicals (O2−•). Meanwhile, the photo-induced holes in ZrO2 may react with adjacent hydroxyl groups (OH−) or adsorbed H2O molecules to produce hydroxyl radicals (•OH). These reactive oxygen species are responsible for the photodegradation of MB, as illustrated in Figure 10.
Figure 11 depicts the extent of the photocatalytic degradation of MB dye both with and without scavengers. In the absence of any quencher, the dye degradation achieved 84%. However, this percentage reduced to 58% and 48% when P-BQ and AO were present, respectively. Notably, the degradation of MB significantly declined to 19% in the presence of t-BuoH, suggesting that electrons play a main role in the photodegradation of MB dye through the formation of ˙O2− radicals.

3. Experimental Work

3.1. Preparation Technique of ZrO2

Zirconium dioxide (ZrO2) nanoparticles were made using a method called the combustion of sol–gel. All the chemicals used in this study, including citric acetate, zirconium nitrate, and DMF, were obtained from Sigma Aldrich, St. Saint Louis, MO, USA. To maintain a consistent citric acid-to-metal cation ratio, the solution was thoroughly mixed at room temperature. To remove the solvent and form a gel, the solution was vigorously stirred at 150 °C while being frequently swirled. The gel precipitate was centrifuged and repeatedly cleaned with ethanol and water in order to cleanse it. Finally, it was heated to 650 °C and ground into a fine powder. Compared to other techniques, sol–gel combustion is a more attractive choice for material synthesis because it is easy to implement, requires minimal resources, and delivers high yields. Because it minimizes waste and maximizes resource utilization, the sol–gel combustion technique complements the closed-loop approach of the circular financial system.

3.1.1. Reduced Graphene Preparation from PET Water Bottle Waste

Wastewater bottles composed of polyethylene terephthalate (PET) were mechanically broken down and sieved using a standard sieve shaker to obtain particles within the size range of 1–3 mm. A 2 g portion of the untreated PET waste was then placed into a 50 mL stainless steel autoclave reactor (SS316). The sealed reactor was positioned in the center of an oven and heated at a rate of 8 °C/min until it reached 800 °C, a temperature maintained for 1 h. Following the annealing treatment, the system was permitted to undergo spontaneous cooling over a 12-h periods. The resulting dark product was collected, characterized, and subsequently crushed. The yield is RGO as shown in Figure S1. The PET waste bottles acted as a precursor material for graphene fabrication, as depicted in Scheme 1.

3.1.2. Synthesis ZrO2@%RGO

Photocatalysts ZrO2@%RGO were produced through an ultrasonic mixing technique. 0.05 g of ZrO2 was disappeared in 30 DI water for several minutes. Following the addition of different concentrations of RGO (0, 0.01, 0.03, and 0.04) and 1 h sonication, the ZrO2 mixture was centrifuged, cleaned, and dried (60 °C, 24 h) to yield ZrO2@%RGO.

3.2. Characterization

Produced via a straightforward chemical route (sol–gel combustion), the nanoparticles were probed employing “a Philips PW 1710 X-ray” diffractometer with “CuKα radiation. (λ = 1.5405 Å)”, EDAX, and SEM). The JASCO 670 UV-Vis double-beam spectrophotometer was used to measure the transmittance spectra. Characterization was performed across the UV-Vis spectrum, from 200 nm to 1000 nm. The degradation of MB was used to test the materials’ photocatalytic capability, a representative organic pollutant. Degradation of the catalyst under light irradiation (photodegradability) was assessed using UV–visible spectroscopy. An analysis of impedance and Mott–Schottky measurements occurred through the Cortest Cs305 workstation system. A 500-watt xenon lamp worked together with 25 mg of photocatalyst material for conducting the photocatalysis experiment.

4. Conclusions

In summary, the ZrO2 coated with various concentrations of RGO compounds is successfully made by the sonication technique. The XRD analysis via X’pert HighScore search reveals that the tetragonal phase of ZrO2 (P 42/nm c:1) is present in all the concentrations of RGO. The peak broadening of all patterns is visible for the synthesized powders when compared to the pure ones, which indicates that they are all noncrystalline. The coated sample relates to the amorphous phase of RGO. The pure ZrO2 without any additives exhibits a smooth surface when compared to the coating of RGO. The multilayer structure of rGO sheets is clearly seen in the SEM image of the RGO-ZrO2 nanocomposite. A sequence of larger aggregated ZrO2 particles is seen on the surface of RGO. The catalytic efficiency of ZrO2 is improved by the formation of ZrO2/RGO composites. Studies revealed ZrO2@4%RGO demonstrated the maximum photocatalytic efficiency among all the weight percentage tests for ZrO2/RGO. The nanocomposite presents a reduced bandgap value that falls from 5.6 eV to 3.87 eV. The Mott–Schottky performance of all semiconductor devices was analyzed at a frequency of 500 Hz. As-synthesized photocatalysts’ flat band potential is 17 × 10−2, 20 × 10−2, 53 × 10−2, and 29 × 10−2 eV vs. SCE for pristine ZrO2 and covered with different amount of 0.01, 0.03, and 0.04 RGO, correspondingly. The ZrO2@4%RGO composite shows a 1.5 times higher MB photocatalytic rate because its reduced band gap allows for effective charge carrier separation and enables enhanced charge transfer through increased surface area. The reduced graphene oxide nanocomposites prove to be ideal materials for sustainable water pollution remediation. The debasement efficiencies of MB utilizing ZrO2 and ZrO2@%RGO under sunshine irradiation were estimated at 65% and 80%, respectively.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/catal15030289/s1, Figure S1: The XRD patterns of RGO and SEM photo of RGO (in set), Figure S2: The Uv-vis spectra of MB in 120 min.

Author Contributions

Conceptualization, N.F. and M.A.E.-O.; methodology, A.A.; software, F.H.A.; validation, A.B.G.T.; formal analysis, E.R.S.; investigation, resources, and data curation, A.M.A.; writing—original draft preparation, all authors. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2025R38), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Data Availability Statement

The data will be available upon reasonable request.

Acknowledgments

The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2025R38), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Conflicts of Interest

The authors declare no conflicts of interest.

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Catalysts 15 00289 g001
Figure 1. (a) The XRD analysis displayed patterns for ZrO2, RGO and ZrO2 covered with various amounts of RGO. (b) The rietveld refinement of pure ZrO2.
Figure 1. (a) The XRD analysis displayed patterns for ZrO2, RGO and ZrO2 covered with various amounts of RGO. (b) The rietveld refinement of pure ZrO2.
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Catalysts 15 00289 g002
Figure 2. (a) SEM photo of pure ZrO2, (b) ZrO2@1%rGO, and (c) ZrO2@4%rGO.
Figure 2. (a) SEM photo of pure ZrO2, (b) ZrO2@1%rGO, and (c) ZrO2@4%rGO.
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Catalysts 15 00289 g003
Figure 3. (a) EDX of pure ZrO2, (b) ZrO2@1%rGO, and (c) ZrO2@4%rGO.
Figure 3. (a) EDX of pure ZrO2, (b) ZrO2@1%rGO, and (c) ZrO2@4%rGO.
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Catalysts 15 00289 g004
Figure 4. The optical energy gap of (a) ZrO2, (b) ZrO2@1%RGO, (c) ZrO2@3%RGO, and (d) ZrO2@4%RGO.
Figure 4. The optical energy gap of (a) ZrO2, (b) ZrO2@1%RGO, (c) ZrO2@3%RGO, and (d) ZrO2@4%RGO.
Catalysts 15 00289 g004
Catalysts 15 00289 g005
Figure 5. Mott–Schottky plots of (a) ZrO2, (b) ZrO2@1%RGO, (c) ZrO2@3%RGO, and (d) ZrO2@4%RGO.
Figure 5. Mott–Schottky plots of (a) ZrO2, (b) ZrO2@1%RGO, (c) ZrO2@3%RGO, and (d) ZrO2@4%RGO.
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Catalysts 15 00289 g006
Figure 6. Electrochemical impedance (EIS) spectra of pristine ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO.
Figure 6. Electrochemical impedance (EIS) spectra of pristine ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO.
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Catalysts 15 00289 g007
Figure 7. Photocatalytic degradation performance for (a) pristine ZrO2, (b) ZrO2@1%RGO, (c) ZrO2@3%RGO, and (d) ZrO2@4%RGO.
Figure 7. Photocatalytic degradation performance for (a) pristine ZrO2, (b) ZrO2@1%RGO, (c) ZrO2@3%RGO, and (d) ZrO2@4%RGO.
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Catalysts 15 00289 g008
Figure 8. (a) Photocatalytic efficiency of pure ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO and (b) Ln(Co/C) vs. time for pure ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO.
Figure 8. (a) Photocatalytic efficiency of pure ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO and (b) Ln(Co/C) vs. time for pure ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO.
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Catalysts 15 00289 g009
Figure 9. (a) Degradation rate of pristine ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO. (b) Stability of the ZrO2@4%RGO for MB removal.
Figure 9. (a) Degradation rate of pristine ZrO2, ZrO2@1%RGO, ZrO2@3%RGO, and ZrO2@4%RGO. (b) Stability of the ZrO2@4%RGO for MB removal.
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Catalysts 15 00289 g010
Figure 10. Reported process for ZrO2/RGO photocatalyzed degradation of MB.
Figure 10. Reported process for ZrO2/RGO photocatalyzed degradation of MB.
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Catalysts 15 00289 g011
Figure 11. The influence of different scavengers on the photocatalytic degradation of MB.
Figure 11. The influence of different scavengers on the photocatalytic degradation of MB.
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Catalysts 15 00289 sch001
Scheme 1. The PET waste bottles acted as a precursor material for reduced graphene fabrication.
Scheme 1. The PET waste bottles acted as a precursor material for reduced graphene fabrication.
Catalysts 15 00289 sch001
Table 1. A comparative evaluation of ZrO2 structures that degrade MB dye through photocatalysts.
Table 1. A comparative evaluation of ZrO2 structures that degrade MB dye through photocatalysts.
CatalystSynthesis MethodDyeIrradiation Source Efficiency, % References
t-ZrO2Green methodMBUV light68[38]
ZrO2BiogenicMOUV light69[39]
Nd-ZrO2Polymer assistedMBVisible light68[40]
ZrO2 NPsHydrothermalMBSunlight80[41]
ZrO2Sol–gel combustionMBSunlight65Our work
ZrO2@4%RGOSol–gel combustionMBSunlight82Our work
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Farghly, N.; Abu El-Oyoun, M.; Abousehly, A.; Alkallas, F.H.; Trabelsi, A.B.G.; Shaaban, E.R.; Aboraia, A.M. Investigating the Photocatalytic Properties of Reduced Graphene Oxide-Coated Zirconium Dioxide and Their Impact on Structural and Morphological Features. Catalysts 2025, 15, 289. https://doi.org/10.3390/catal15030289

AMA Style

Farghly N, Abu El-Oyoun M, Abousehly A, Alkallas FH, Trabelsi ABG, Shaaban ER, Aboraia AM. Investigating the Photocatalytic Properties of Reduced Graphene Oxide-Coated Zirconium Dioxide and Their Impact on Structural and Morphological Features. Catalysts. 2025; 15(3):289. https://doi.org/10.3390/catal15030289

Chicago/Turabian Style

Farghly, Norhan, M. Abu El-Oyoun, A. Abousehly, Fatemah H. Alkallas, Amira Ben Gouider Trabelsi, E. R. Shaaban, and Abdelaziz Mohamed Aboraia. 2025. "Investigating the Photocatalytic Properties of Reduced Graphene Oxide-Coated Zirconium Dioxide and Their Impact on Structural and Morphological Features" Catalysts 15, no. 3: 289. https://doi.org/10.3390/catal15030289

APA Style

Farghly, N., Abu El-Oyoun, M., Abousehly, A., Alkallas, F. H., Trabelsi, A. B. G., Shaaban, E. R., & Aboraia, A. M. (2025). Investigating the Photocatalytic Properties of Reduced Graphene Oxide-Coated Zirconium Dioxide and Their Impact on Structural and Morphological Features. Catalysts, 15(3), 289. https://doi.org/10.3390/catal15030289

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