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Journal articles on the topic 'ZnO photocatalysis'
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1
Teye, Godfred Kwesi, Jingyu Huang, Yi Li, Ke Li, Lei Chen, and Williams Kweku Darkwah. "Photocatalytic Degradation of Sulfamethoxazole, Nitenpyram and Tetracycline by Composites of Core Shell g-C3N4@ZnO, and ZnO Defects in Aqueous Phase." Nanomaterials 11, no. 10 (October 4, 2021): 2609. http://dx.doi.org/10.3390/nano11102609.
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The synthesis of photocatalysts with high charge separation and transfer efficiency are of immense significance in the process of using photocatalysis technology for wastewater treatment. In this study core shell g-C3N4@ZnO, and ZnO defects photocatalysts presented an improved morphology in its characterization using techniques such as SEM, DRS, PL, MS, EIS, and XRD, and enhanced photodegradation of sulfamethoxazole, Nitenpyram and Tetracycline. Different composites were obtained as confirmed by the various characterization techniques studied, including core shell g-C3N4@ZnO, and ZnO defects photocatalyst. The synthesized photocatalysts showed high visible light absorption efficiency within a range of ~655 to 420 nm. Core shell g-C3N4@ZnO, and ZnO defects photocatalysts demonstrated high photocatalytic activity ascribed to high load separation and transition as shown in PL, Photocurrent reaction and EIS. It is understandable that core shell g-C3N4@ZnO, and ZnO defects photocatalysts have been confirmed to be one of the ultimate promising entrants for photocatalyst scheming.
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Pujiarti, Yuly, Suyanta Suyanta, and Eko Sri Kunarti. "A Visible Light-Induced Fe3O4/ZnO-Cu Nanocomposite and its Photocatalytic Activities for Rhodamine B Photodegradation." Key Engineering Materials 884 (May 2021): 60–66. http://dx.doi.org/10.4028/www.scientific.net/kem.884.60.
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Synthesis of Fe3O4/ZnO-Cu nanocomposite photocatalyst has been conducted. The synthesis was carried out using the co-precipitation method with the variation of Cu concentration and modification by Fe3O4 magnetic material. As synthesized photocatalysts were characterized using FTIR, XRD, TEM, and SR UV-Visible. Photocatalytic activities of samples were evaluated through Rhodamine B degradation under visible light irradiation. The results showed that a sample with Fe3O4/ZnO-Cu 1% has smaller band gap energy of 2.90 eV and the highest photocatalytic activity than pure ZnO or Fe3O4-modified ZnO (Fe3O4/ZnO-Cu 0%) under visible light. The percentage of Rhodamine B degradation was approximately 89.41% during 120 min of visible light illumination. Moreover, the photocatalyst materials could be easily separated after photocatalysis which is due to the magnetic property of Fe3O4 material. Therefore, Cu-doped ZnO with Fe3O4 modification has been an efficient and effective visible-light-induced photocatalyst in removing non-biodegradable Rhodamine B dyes.
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Sánchez, Luis A., Brian E. Huayta, Pierre G. Ramos, and Juan M. Rodriguez. "Enhanced Photocatalytic Activity of ZnO Nanorods/(Graphene Oxide, Reduced Graphene Oxide) for Degradation of Methyl Orange Dye." Journal of Physics: Conference Series 2172, no. 1 (February 1, 2022): 012013. http://dx.doi.org/10.1088/1742-6596/2172/1/012013.
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Abstract ZnO has been well-known as a significant photocatalyst material due to its high surface area, efficient charge transport, and superior photosensitivity. Even though photocatalysis using bare ZnO NRs is useful in pollutant remediation, two main drawbacks scale down their performance as photocatalysts. First, ZnO NRs absorb mainly the UV light, which compromises a small portion of the solar spectrum, and second, the high recombination rate in the ZnO NRs prevents the path of electron-hole outward and then reduces the photocatalysis efficiency. In this work, ZnO-NRs, ZnO-NRs/Graphene Oxide (GO), and ZnO-NRs/Reduced Graphene Oxide (rGO) array composites were vertically grown on conductive glass substrates of SnO2:F (FTO). The films were synthesized by hydrothermal method using ZnO seed layers deposited by spray pyrolysis technique. The nanosheets of GO and rGO were anchored onto the surface of the as-prepared ZnO-NRs by using the spray deposition technique (SDT). The photocatalytic activity of these materials was studied by analyzing the degradation of methylene orange (MO) in an aqueous solution under ultraviolet light, and we found that the decoration of ZnO-NRs with nanosheets of GO and rGO resulted in a significant enhancement of the photocatalytic degradation efficiency, where ZnO-NRs/rGO are more efficient than ZnO-NRs/GO and the latter better than pure ZnO-NRs.
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Loka, Chadrasekhar, and Kee-Sun Lee. "Enhanced Visible-Light-Driven Photocatalysis of Ag/Ag2O/ZnO Nanocomposite Heterostructures." Nanomaterials 12, no. 15 (July 23, 2022): 2528. http://dx.doi.org/10.3390/nano12152528.
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Visible-light-driven photocatalysis is one promising and efficient approach for decontaminating pollutants. Herein, we report the combination of localized surface plasmon resonance (LSPR) and p-n heterojunction structure Ag-Ag2O-ZnO nanocomposite synthesized by a hydrothermal process for the suppression of photogenerated electron-hole pair recombination rates, the extension of the absorption edge to the visible region, and the enhancement of photocatalytic efficiency. The prepared nanocomposites were investigated by standard analytical techniques and the results revealed that the synthesized powders were comprised of Ag, Ag2O, and ZnO phases. Photocatalytic activity of the photocatalyst tested for methylene blue, methyl orange, and rhodamine B showed the highest photocatalytic degradation efficiency: 97.3%, 91.1%, and 94.8% within 60 min under visible-light irradiation. The average lifetime of the photogenerated charge carriers was increased twofold in the Ag-Ag2O-ZnO photocatalyst (~10 ns) compared to the pure ZnO (~5.2 ns). The enhanced photocatalytic activity resulted from a decrease of the charge carrier recombination rate as inferred from the steady-state and time-resolved photoluminescence investigations, and the increased photoabsorption ability. The Ag-Ag2O-ZnO photocatalyst was stable over five repeated cyclic photodegradation tests without showing any significant changes in performance. Additionally, the structure indicated a potential for application in environmental remediation. The present study showcases the robust design of highly efficient and reusable visible-light-active photocatalysts via the combination of p-n heterojunction and LSPR phenomena.
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Kočí, Kamila, Martin Reli, Ivana Troppová, Marcel Šihor, Tereza Bajcarová, Michal Ritz, Jiří Pavlovský, and Petr Praus. "Photocatalytic Decomposition of N2O by Using Nanostructured Graphitic Carbon Nitride/Zinc Oxide Photocatalysts Immobilized on Foam." Catalysts 9, no. 9 (August 30, 2019): 735. http://dx.doi.org/10.3390/catal9090735.
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The aim of this work was to deposit cost-effective g-C3N4/ZnO nanocomposite photocatalysts (weight ratios of g-C3N4:ZnO from 0.05:1 to 3:1) as well as pure ZnO and g-C3N4 on Al2O3 foam and to study their photocatalytic efficiency for the photocatalytic decomposition of N2O, which was studied in a home-made batch photoreactor under ultraviolet A irradiation (λ = 365 nm). Based on the photocatalysis measurements, it was found that photocatalytic decomposition of N2O in the presence of all the prepared samples was significantly higher in comparison with photolysis. The photoactivity of the investigated nanocomposite photocatalysts increased in the following order: g-C3N4/ZnO (3:1) ≈ g-C3N4/ZnO (0.45:1) ≤ g-C3N4/ZnO (2:1) ZnO < g-C3N4 < g-C3N4/ZnO (0.05:1). The g-C3N4/ZnO (0.05:1) nanocomposite showed the best photocatalytic behavior and the most effective separation of photoinduced electron–hole pairs from all nanocomposites. The key roles played in photocatalytic activity were the electron–hole separation and the position and potential of the valence and conduction band. On the other hand, the specific surface area and band gap energy were not the significant factors in N2O photocatalytic decomposition. Immobilization of the photocatalyst on the foam permits facile manipulation after photocatalytic reaction and their repeated application.
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Le Pivert, Marie, Nathan Martin, and Yamin Leprince-Wang. "Hydrothermally Grown ZnO Nanostructures for Water Purification via Photocatalysis." Crystals 12, no. 3 (February 22, 2022): 308. http://dx.doi.org/10.3390/cryst12030308.
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Semiconductor-based photocatalysis is a well-known and efficient process for achieving water depollution with very limited rejects in the environment. Zinc oxide (ZnO), as a wide-bandgap metallic oxide, is an excellent photocatalyst, able to mineralize a large scale of organic pollutants in water, under UV irradiation, that can be enlarged to visible range by doping nontoxic elements such as Ag and Fe. With high surface/volume ratio, the ZnO nanostructures have been shown to be prominent photocatalyst candidates with enhanced photocatalytic efficiency, owing to their being low-cost, non-toxic, and able to be produced with easy and controllable synthesis. Thus, ZnO nanostructures-based photocatalysis can be considered as an eco-friendly and sustainable process. This paper presents the photocatalytic activity of ZnO nanostructures (NSs) grown on different substrates. The photocatalysis has been carried out both under classic mode and microfluidic mode. All tests show the notable photocatalytic efficiency of ZnO NSs with remarkable results obtained from a ZnO-NSs-integrated microfluidic reactor, which exhibited an important enhancement of photocatalytic activity by drastically reducing the photodegradation time. UV-visible spectrometry and high-performance liquid chromatography, coupled with mass spectrometry (HPLC-MS), are simultaneously used to follow real-time information, revealing both the photodegradation efficiency and the degradation mechanism of the organic dye methylene blue.
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Zhang, Yangyang, Manoj K. Ram, Elias K. Stefanakos, and D. Yogi Goswami. "Synthesis, Characterization, and Applications of ZnO Nanowires." Journal of Nanomaterials 2012 (2012): 1–22. http://dx.doi.org/10.1155/2012/624520.
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ZnO nanowires (or nanorods) have been widely studied due to their unique material properties and remarkable performance in electronics, optics, and photonics. Recently, photocatalytic applications of ZnO nanowires are of increased interest in environmental protection applications. This paper presents a review of the current research of ZnO nanowires (or nanorods) with special focus on photocatalysis. We have reviewed the semiconducting photocatalysts and discussed a variety of synthesis methods of ZnO nanowires and their corresponding effectiveness in photocatalysis. We have also presented the characterization of ZnO nanowires from the literature and from our own measurements. Finally, a wide range of uses of ZnO nanowires in various applications is highlighted in this paper.
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Su, Xiaowen, Xiaolei Zhao, Chao Cui, Ning Xi, Xiao Li Zhang, Hong Liu, Xiaowen Yu, and Yuanhua Sang. "Influence of Wurtzite ZnO Morphology on Piezophototronic Effect in Photocatalysis." Catalysts 12, no. 9 (August 25, 2022): 946. http://dx.doi.org/10.3390/catal12090946.
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A piezoelectric field promotes the photocatalytic activity of a photocatalyst by helping separating photo-generated charge carriers. Wurtzite phase ZnO is a typical photocatalyst with a piezoelectric property, thus self-assisted photocatalysis with ZnO based on the piezophototronic effect can be achieved. ZnO nanorods or nanowires with a clear c-axis have been well studied, while other morphologies have not been fully discussed. In this work, we prepared wurtzite phase ZnO with four different morphologies. By comparing their photocatalytic activity for degradation of Rhodamine B under the same mechanical energy source provided by ultrasound, the effect of morphology and exposed facets on photo-induced charge separation were highlighted. The ZnO nanowire photocatalyst delivered an impressive improvement in photocatalytic efficiency when ultrasound driven, suggesting that the morphology-related piezophototronic effect had a positive effect on separation of photo-generated charge carriers, and more exposed active facets benefitted the utilization of charge carriers.
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Sayury Miyashiro, Carolina, and Safia Hamoudi. "Palladium and Graphene Oxide Doped ZnO for Aqueous Acetamiprid Degradation under Visible Light." Catalysts 12, no. 7 (June 28, 2022): 709. http://dx.doi.org/10.3390/catal12070709.
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Acetamiprid is a neonicotinoid insecticide widely used in pest control. In recent years, it has been considered as a contaminant in groundwater, lakes, and rivers. Photocatalysis under visible light radiation proved to be an effective process for getting rid of several organic pollutants. In the present work, photodegradation of aqueous acetamiprid was investigated over bare zinc oxide (ZnO) photocatalyst as well as ZnO doped with either palladium or palladium combined with graphene oxide. Both ZnO and doped-ZnO were synthesized via a microwave-assisted hydrothermal procedure. The obtained photocatalysts were characterized using different techniques. After 5 h of reaction at ambient temperature under visible light irradiation, acetamiprid conversions attained ca. 38, 82, and 98% in the presence of bare ZnO, Pd-doped ZnO and Pd-GO-doped ZnO photocatalysts, respectively, thus demonstrating the positive effect of Pd- and GO-doping on the photocatalytic activity of ZnO. In addition, Pd-GO-doped ZnO was shown to keep its activity even when it is recycled five times, thus proving its stability in the reaction medium.
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El-Sayed, Fatma, Mai S. A. Hussien, Thekrayat H. AlAbdulaal, Ahmed Ismail, Heba Y. Zahran, Ibrahim S. Yahia, Mohamed Sh Abdel-wahab, Yasmin Khairy, Tarik E. Ali, and Medhat A. Ibrahim. "Comparative Degradation Studies of Carmine Dye by Photocatalysis and Photoelectrochemical Oxidation Processes in the Presence of Graphene/N-Doped ZnO Nanostructures." Crystals 12, no. 4 (April 11, 2022): 535. http://dx.doi.org/10.3390/cryst12040535.
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The goal of this study was to synthesize a UV-light-active ZnO photocatalyst by modifying it with nitrogen and graphene, then applying it to the degradation of carmine dye utilizing two promising technologies: photocatalysis and electrochemical oxidation (E.O.). Different techniques were used to analyze the prepared photocatalysts, such as Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). According to XRD measurements, the produced nanocomposite possesses a hexagonal wurtzite structure, indicating ZnO and markedly crystalline. For photocatalytic applications, the results revealed that the 0.001 g of G/N-doped ZnO catalyst achieved 66.76% degradation of carmine and kinetic degradation rates of 0.007 min−1 within 185 min by photocatalysis under UV light irradiation. In comparison, the same sample reached 100% degradation of carmine and kinetic degradation rates of 0.202 min−1 within 15 min using the electrochemical oxidation method. The improved photocatalytic activity of as-produced nanocomposites can be attributed to intermediate levels in the prohibited bandgap energy and the enhanced oxygen vacancies caused by nitrogen doping. The electrolyte (NaCl) on the degradation of the carmine dye was tested, and the findings indicated that the dye molecules were photodegraded by the 0.001 g of G/N-doped ZnO nanocomposite after a 15 min time interval. The data presented in this work for the carmine breakdown in water give intriguing contrasts between photocatalytic, indirect electrochemical oxidation, and photoelectrochemical oxidation. The action of chlorinated oxidative species, predominantly HClO, which were electrogenerated at the electrode surface due to the chloride ion’s oxidation in solution, induced indirect electrochemical oxidation degradation. This study also revealed that the modifications made to ZnO were beneficial by improving its photocatalytic activities under UV light, as well as a comparison of photocatalysis and electrochemical oxidation processes to determine which technique is best for treating carmine in effluents with high chloride ions.
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Денисюк, И. Ю., Д. А. Морозова, Ю. А. Игнатьева, and М. В. Успенская. "Создание ZnO нанокатализатора, фиксированного на подложке, и перспективы фотокаталитического получения биогаза из растительных отходов." Оптика и спектроскопия 129, no. 6 (2021): 787. http://dx.doi.org/10.21883/os.2021.06.50994.314-20.
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In this work discuss the production of biofuels from agricultural waste, such as sugars, alcohols, organic acids, by obtaining hydrogen and biogas from them during photocatalytic decomposition. Possible chemical reactions during photocatalysis are presented using the example of photocatalytic decomposition of methanol into hydrogen and carbon dioxide. Experiments on the preparation of nanostructured ZnO by the hydrothermal method in a solution containing zinc acetate and urotropin have been carried out. The obtained ZnO immobilized on a substrate is supposed to be used as a photocatalyst. A possible design of a reaction vessel and radiation sources for a laboratory setup for producing biogas from model solutions are considered. Key words: photocatalysis, biogas, ZnO, nanowires, waste disposal, renewable energy.
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Baruah, Sunandan, Mohammad Abbas Mahmood, Myo Tay Zar Myint, Tanujjal Bora, and Joydeep Dutta. "Enhanced visible light photocatalysis through fast crystallization of zinc oxide nanorods." Beilstein Journal of Nanotechnology 1 (November 22, 2010): 14–20. http://dx.doi.org/10.3762/bjnano.1.3.
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Hydrothermally grown ZnO nanorods have inherent crystalline defects primarily due to oxygen vacancies that enhance optical absorption in the visible spectrum, opening up possibilities for visible light photocatalysis. Comparison of photocatalytic activity of ZnO nanorods and nanoparticle films on a test contaminant methylene blue with visible light irradiation at 72 kilolux (klx) showed that ZnO nanorods are 12–24% more active than ZnO nanoparticulate films. This can be directly attributed to the increased effective surface area for adsorption of target contaminant molecules. Defects, in the form of interstitials and vacancies, were intentionally created by faster growth of the nanorods by microwave activation. Visible light photocatalytic activity was observed to improve by ≈8% attributed to the availability of more electron deficient sites on the nanorod surfaces. Engineered defect creation in nanostructured photocatalysts could be an attractive solution for visible light photocatalysis.
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Johar, Muhammad Ali, Rana Arslan Afzal, Abdulrahman Ali Alazba, and Umair Manzoor. "Photocatalysis and Bandgap Engineering Using ZnO Nanocomposites." Advances in Materials Science and Engineering 2015 (2015): 1–22. http://dx.doi.org/10.1155/2015/934587.
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Nanocomposites have a great potential to work as efficient, multifunctional materials for energy conversion and photoelectrochemical reactions. Nanocomposites may reveal more improved photocatalysis by implying the improvements of their electronic and structural properties than pure photocatalyst. This paper presents the recent work carried out on photoelectrochemical reactions using the composite materials of ZnO with CdS, ZnO with SnO2, ZnO with TiO2, ZnO with Ag2S, and ZnO with graphene and graphene oxide. The photocatalytic efficiency mainly depends upon the light harvesting span of a material, lifetime of photogenerated electron-hole pair, and reactive sites available in the photocatalyst. We reviewed the UV-Vis absorption spectrum of nanocomposite and photodegradation reported by the same material and how photodegradation depends upon the factors described above. Finally the improvement in the absorption band edge of nanocomposite material is discussed.
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Li, Chao, Huijuan Li, Guicheng He, Zhiwu Lei, and Wenyuan Wu. "Preparation and Photocatalytic Performance of ZnO/Sepiolite Composite Materials." Advances in Materials Science and Engineering 2021 (June 16, 2021): 1–17. http://dx.doi.org/10.1155/2021/5357843.
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Photocatalytic technology is a widely used water treatment method, whose efficiency can be increased by developing a suitable photocatalyst fabrication procedure. In this study, five different synthesis methods were utilised for the preparation of novel ZnO/sepiolite photolytic composites, namely, sol-gel method, hydrothermal reduction, hydrolytic precipitation, powder sintering, and impregnation-reduction. The obtained photocatalysts were characterised by scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The differences between the applied photocatalyst preparation methods and the reasons for these differences were discussed, and the photocatalytic activities of the prepared composite materials were compared. The obtained results revealed that the physical structure, chemical properties, and photocatalytic performance of the composite produced by the sol-gel method were superior to those of the materials fabricated by the other four methods. Moreover, this material also exhibited high photocatalytic stability, while its photocatalytic degradation of methylene blue dye proceeded via a quasi-first-order reaction. The prepared composites have broad application prospects in photocatalysis and can be potentially used for treating environmental pollutants.
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BARUAH, SUNANDAN, RAHMAN FAIZUR RAFIQUE, and JOYDEEP DUTTA. "VISIBLE LIGHT PHOTOCATALYSIS BY TAILORING CRYSTAL DEFECTS IN ZINC OXIDE NANOSTRUCTURES." Nano 03, no. 05 (October 2008): 399–407. http://dx.doi.org/10.1142/s179329200800126x.
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The photocatalytic activity of zinc oxide ( ZnO ) nanoparticles, films and nanowires as a potential visible light photocatalyst is presented in this work. ZnO nanoparticles were synthesized in different alcoholic solvents. Crystal defects were introduced either by doping the crystallites with manganese or by fast crystallization (using microwave irradiation during synthesis). ZnO , with a band gap of 3.37 eV, normally absorbs electromagnetic waves in the ultraviolet region, but introducing defects into its crystal lattice can shift the absorption more toward the visible light band from 400 nm to 700 nm by creating intermediate states which inhibit electron–hole recombination. The undoped ZnO nanoparticles synthesized using microwaves showed comparable photocatalytic activities to the doped samples using the conventional heating method. To increase the effective surface area of the photocatalyst, ZnO nanowires were grown by a solution-based technique. Methylene blue degradation was observed to be enhanced in the presence of the ZnO nanowires compared to the ZnO nanoparticles. Intentional defect creation in photocatalysts could be an attractive possibility to apply in the visible light photocatalytic degradation studies.
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Gao, Lan, Elyes Nefzaoui, Frédéric Marty, Mazen Erfan, Stéphane Bastide, Yamin Leprince-Wang, and Tarik Bourouina. "TiO2-Coated ZnO Nanowire Arrays: A Photocatalyst with Enhanced Chemical Corrosion Resistance." Catalysts 11, no. 11 (October 27, 2021): 1289. http://dx.doi.org/10.3390/catal11111289.
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Photocatalysis is proven to be the most efficient and environmentally friendly method for the degradation of organic pollutants in water purification. To meet the requirement of large-scale water treatment, there are two important points: One is the lifetime and chemical stability of the photocatalyst material, especially in the complex and harsh aqueous conditions. The other is the ease of synthesis of such photocatalysts with specific nano-morphology. In this work, two common photocatalyst materials, zinc oxide (ZnO) and titanium dioxide (TiO2), are selected to form more sustainable photocatalysts with high chemical stability. This involves the combination of both TiO2 and ZnO in a two-step simple synthesis method. It appears advantageous to exploit the conformal deposition of atomic layer deposition (ALD) to achieve nanometer-thick TiO2 coating on ZnO nanowires (NWs) with a high aspect ratio, which are firmly anchored to a substrate and exhibit a large specific surface area. The high chemical stability of the ALD TiO2 coating has been investigated in detail and proven to be effective under both strong acid and strong alkaline aqueous solutions. In addition, photocatalysis experiments with organic dyes show that via this simple two-step synthesis method, the produced ZnO/TiO2 tandem photocatalysts does indeed exhibit improved chemical stability in a harsh environment, while allowing efficient photodegradation.
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Almeida Guerra, Wilson N., Joana M. Teixeira Santos, and Lucia R. Raddi de Araujo. "Decolorization and mineralization of reactive dyes by a photocatalytic process using ZnO and UV radiation." Water Science and Technology 66, no. 1 (July 1, 2012): 158–64. http://dx.doi.org/10.2166/wst.2012.154.
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Reactive dyes are one of the major pollutants in textile wastewater and a concern because they are not easily degraded by conventional wastewater treatments. Heterogeneous photocatalysis has been considered an effective option for treating wastewater containing those dyes. This research work assesses the photocatalytic degradation of reactive dyes using UV irradiation and pure or impregnated ZnO. In addition to photocatalysis, separate photolysis and adsorption experiments were conducted but showed low efficiency. The dye degradation was monitored by UV–Vis spectroscopy and mineralization was determined by total organic carbon (TOC) analyses. Total color removal was achieved after 30 min of irradiation using pure ZnO. The Black 5 dye photocatalytic decolorization reaction followed first-order kinetics, while Yellow 145, Red 4 and Blue 21 dyes followed zero-order kinetics. TOC removals in the range of 70–80% were achieved after 240 min of individual photocatalytic treatment with ZnO. The performance of each photocatalyst was also compared when the four dyes were mixed together and the order of efficiency in the mineralization process was as follows: Fe/ZnO > ZnO > Co/ZnO. This result was explained by the crystal field theory.
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Wu, Chun Du, Kun Zheng, and Qing Jie Xie. "The Primary Study of Synthesis and Photocatalytic Activity of ZnO/Nickel-Zinc Ferrite Magnetic Photocatalyst." Advanced Materials Research 955-959 (June 2014): 154–57. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.154.
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Magnetic photocatalyst ZnO/nickel-zinc ferrite powders were synthesized by two-step method: First ,nickel-zinc ferrite powders were prepared by coprecipitation method and then ZnO /nickel-zinc ferrite composite powders were prepared by the homogeneous precipitation method. The as-prepared sample was characterized by X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM), the photocatalysis of the catalyst was evaluated with methylene blue as decomposition substance and the photocatalytic activity of the material has been tested on decomposable substrate under visible-light in the magnetic photocatalytic wastewater treatment reactor. The results demonstrate that the magnetic photocatalyst ZnO/nickel-zinc ferrite powders exhibit highly efficient visible-light-driven photocatalytic activity, the degradation rate of methylene blue is 84%.
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Xu, Xiao Nan, Qiu Ping Zhang, Brain T. M. Ong, Huan Yuan, Yu Chen, Yu Tong Liu, and Ming Xu. "Influence of Stabilizer on the Microstructures and Photocatalytic Performance of ZnO Nanopowder Synthesized by Sol-Gel Method." Journal of Nano Research 50 (November 2017): 57–71. http://dx.doi.org/10.4028/www.scientific.net/jnanor.50.57.
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Utilizing zinc acetate as precursor, and monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) as stabilizers, respectively, ZnO nanoparticles with uniformly distributed grains were synthesized by sol-gel method at different sintering temperatures. Analysis of the degradation of methyl orange by photocatalysis shows that utilizing MEA as the stabilizer and 550°C as the sintering temperature results in smaller grain size, greater surface-to-volume ratio, and a density of surface defects suitable for a photocatalyst. The greatest photocatalytic degradation of methyl orange was achieved under UV irradiation. Based on our microstructural analysis and photocatalysis, the microstructure of ZnO particles and, in turn, their photocatalytic effect are affected significantly by the stabilizer type and the sintering temperature.
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Khiari, Mouna, Mickaël Gilliot, Michaël Lejeune, Florica Lazar, and Aomar Hadjadj. "Effects of Ag Nanoparticles on Zinc Oxide Photocatalytic Performance." Coatings 11, no. 4 (March 31, 2021): 400. http://dx.doi.org/10.3390/coatings11040400.
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We used a sol–gel spin coating technique to synthesize nanocomposite thin films based on zinc oxide (ZnO) loaded with silver nanoparticles (NPs). We tested these ZnO/Ag NPs photocatalysts, with a thickness of about 100 nm, for the photodegradation of the indigo carmine dye solution. The study focused on the effects of Ag NPs on the ZnO matrix as well as the impact of their concentration on the photocatalytic performance of the nanocomposite. The study also highlighted the high stability of the photocatalytic performance of these nanocomposites. This work is a contribution in the search for non-toxic thin film photocatalysts that is usable under solar radiation for the treatment of contaminated wastewater. Innovation in the field of heterogeneous photocatalysis requires the use of solar resource with efficient results in terms of photocatalytic performance.
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Chen, Lan-li, Bao-gai Zhai, and Yuan Ming Huang. "Rendering Visible-Light Photocatalytic Activity to Undoped ZnO via Intrinsic Defects Engineering." Catalysts 10, no. 10 (October 11, 2020): 1163. http://dx.doi.org/10.3390/catal10101163.
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It is significant to render visible-light photocatalytic activity to undoped ZnO nanostructures via intrinsic defect engineering. In this work, undoped ZnO nanocrystals were derived via co-precipitation synthesis. The resulting ZnO nanocrystals were characterized by means of X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, and ultraviolet-visible absorption spectroscopy, respectively. The visible-light photocatalytic activity of the products were characterized by monitoring the decomposition of methyl orange in water under visible-light illumination of a 300 W halogen lamp. It is found that undoped ZnO nanocrystals exhibit visible-light photocatalytic activity with their first-order rate constant up to 4.6 × 10−3 min−1. Density functional calculations show that oxygen vacancies create deep energy levels at EV + 0.76 eV in the bandgap of ZnO. In conjunction with the density functional calculations, the photocatalytic degradation of methyl orange under visible-light irradiation provides direct evidence that oxygen vacancies in ZnO nanocrystals yield the visible-light photocatalytic activity. Our results demonstrate that visible-light photocatalytic activity can be endowed to undoped ZnO nanocrystals by manipulating the intrinsic defects in ZnO. Intrinsic defect-modulated ZnO photocatalysts thus represent a powerful configuration for further development toward visible-light responsive photocatalysis.
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Li, Chao, Huijuan Li, Chengzhi Pu, and Zhiwu Lei. "PREPARATION OF ZNO/SEPIOLITE COMPOSITE AND ITS PHOTOCATALYTIC PERFORMANCE FOR THE WATER DECONTAMINATION." DYNA 96, no. 4 (July 1, 2021): 401–6. http://dx.doi.org/10.6036/10176.
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The photocatalysis technology has become an important means to control environmental pollutions especially water pollution. A new ZnO/sepiolite composite was prepared using the sol–gel method by taking the nontoxicity, high catalytic activity, high stability, and strong antioxidant capacity of ZnO and the large pore volume and specific surface area, strong adsorption capacity, light weight, and strong chemical stability of sepiolite to prepare improved photocatalytic materials. The microrepresentation and contrast analysis of structures and morphologies of sepiolite and ZnO/sepiolite composite were performed using scanning electron microscopy, Fourier transform infrared spectrometry, and TD-3500 X-ray diffraction. The degradation capacities of sepiolite, ZnO, and ZnO/sepiolite composite into formaldehyde, malachite green, methylbenzene, and landfill leachate were tested under UV light. Results show that ZnO can be loaded onto sepiolite successfully and that ZnO ions form a tight coupling interface after entering the sepiolite layer. The formed crystals are small. The pore ratio increases synonyms, and the adsorption performance improves accordingly. Moreover, sepiolite can inhibit the agglomeration of ZnO particles effectively. The ZnO/sepiolite composite is significantly superior to sepiolite and ZnO in the treatmenting of above pollutants. The composite has degraded 88.57% of formaldehyde, 91.3% of malachite green, 66.53% of methylbenzene, and 76.38% of landfill leachate. Compared with other types of composite photocatalyst, the ZnO/sepiolite composite has better photocatalytic performances, and its degradation of organic pollutants conforms to the first-order kinetics. Finally, the ZnO/sepiolite composite has high reusability due to easy recovery and good chemical and photocatalytic stabilities. The ZnO/sepiolite composite provides a new selection to control environmental pollutions and possesses promising application prospects. Keywords: ZnO, sepiolite, preparation, composite, photocatalysis
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Kumar, Santosh, Fei Ye, Babak Mazinani, Sergey Dobretsov, and Joydeep Dutta. "Chitosan Nanocomposite Coatings Containing Chemically Resistant ZnO–SnOx Core–shell Nanoparticles for Photocatalytic Antifouling." International Journal of Molecular Sciences 22, no. 9 (April 26, 2021): 4513. http://dx.doi.org/10.3390/ijms22094513.
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Functional nanocomposites with biopolymers and zinc oxide (ZnO) nanoparticles is an emerging application of photocatalysis in antifouling coatings. The reduced chemical stability of ZnO in the acidic media in which chitosan is soluble affects the performance of chitosan nanocomposites in antifouling applications. In this study, a thin shell of amorphous tin dioxide (SnOx) was grown on the surface of ZnO to form ZnO–SnOx core–shell nanoparticles that improved the chemical stability of the photocatalyst nanoparticles, as examined at pH 3 and 6. The photocatalytic activity of ZnO–SnOx in the degradation of methylene blue (MB) dye under visible light showed a higher efficiency than that of ZnO nanoparticles due to the passivation of electronic defects. Chitosan-based antifouling coatings with varying percentages of ZnO or ZnO–SnOx nanoparticles, with or without the glutaraldehyde (GA) crosslinking of chitosan, were developed and studied. The incorporation of photocatalysts into the chitosan matrix enhanced the thermal stability of the coatings. Through a mesocosm study using running natural seawater, it was found that chitosan/ZnO–SnOx/GA coatings enabled better inhibition of bacterial growth compared to chitosan coatings alone. This study demonstrates the antifouling potential of chitosan nanocomposite coatings containing core–shell nanoparticles as an effective solution for the prevention of biofouling.
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Shang, Jiaxin, Wei Zou, Pengbo Wang, Aowen Li, Meimei Zhou, Pingping Luo, and Jiahui Li. "Preparation and Characterization of Hollow Zinc Oxide Nanofibers and Investigation of Its Photocatalytic Properties." Journal of Nanoelectronics and Optoelectronics 16, no. 1 (January 1, 2021): 64–71. http://dx.doi.org/10.1166/jno.2021.2927.
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Hollow inorganic nanofibers have great potential application in the field of photocatalysis due to their special three-dimensional structure. In our work, we have fabricated ZnO hollow nanofibers (ZnO-HNF) by simple single-spinneret electrospinning of polyacrylonitrile (PAN)/zinc acetate precursor solution, followed by stepwise annealing at 300–500 °C. The results show that long and continuous ZnO-HNF with shell consisting of uniform compacted ZnO nanoparticles are successfully fabricated, and the shell thickness is approximately 30 nm. The formation mechanism of ZnO-HNF is speculated to be consequence of the different rate of mass diffusion during the annealing process (Kirkendall effect). The prepared Zn-HNF exhibits good performance in photocatalysis. The photocatalytic removal efficiency of Rhodamine B (RhB) under ultraviolet light irradiation can reach 94.08% in 1 hour, and the removal efficiency of Cr(VI) is 94.49% in 2 hours. This work provides new ideas for the development of ZnO in the field of photocatalysis, and provides new possibilities for more types of subsequent photocatalytic materials.
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Sá, Alexandro S., Rodrigo P. Feitosa, Luzia Honório, Ramón Peña-Garcia, Luciano C. Almeida, Juliana S. Dias, Lorena P. Brazuna, et al. "A Brief Photocatalytic Study of ZnO Containing Cerium towards Ibuprofen Degradation." Materials 14, no. 19 (October 8, 2021): 5891. http://dx.doi.org/10.3390/ma14195891.
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Ibuprofen (IBU) is one of the most-sold anti-inflammatory drugs in the world, and its residues can reach aquatic systems, causing serious health and environmental problems. Strategies are used to improve the photocatalytic activity of zinc oxide (ZnO), and thosethat involvethe inclusion of metalhave received special attention. The aim of this work was to investigate the influence of the parameters and toxicity of a photoproduct using zinc oxide that contains cerium (ZnO-Ce) for the photodegradation of ibuprofen. The parameters include the influence of the photocatalyst concentration (0.5, 0.5, and 1.5 g L−1) as well as the effects of pH (3, 7, and 10), the effect of H2O2, and radical scavengers. The photocatalyst was characterized by Scanning Electron Microscopy-Energy Dispersive Spectroscopy, Transmission electron microscopy, Raman, X-Ray Diffraction, surface area, and diffuse reflectance. The photocatalytic activity of ibuprofen was evaluated in an aqueous solution under UV light for 120 min. The structural characterization by XRD and SEM elucidated the fact that the nanoparticle ZnO contained cerium. The band gap value was 3.31 eV. The best experimental conditions for the photodegradation of IBU were 60% obtained in an acidic condition using 0.50 g L−1 of ZnO-Ce in a solution of 20 ppm of IBU. The presence of hydrogen peroxide favored the photocatalysis process. ZnO-Ce exhibited good IBU degradation activity even after three photocatalytic cycles under UV light. The hole plays akey role in the degradation process of ibuprofen. The toxicity of photolyzed products was monitored against Artemia salina (bioindicator) and did not generate toxic metabolites. Therefore, this work provides a strategic design to improve ZnO-Ce photocatalysts for environmental remediation.
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Gerawork, Mekdes. "Remediation of textile industry organic dye waste by photocatalysis using eggshell impregnated ZnO/CuO nanocomposite." Water Science and Technology 83, no. 11 (April 29, 2021): 2753–61. http://dx.doi.org/10.2166/wst.2021.165.
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Abstract Heterogeneous photocatalysis using nanocomposites is of great research interest in the treatment of industrial wastewater. The impregnated photocatalyst was produced by liquid state reaction of ZnO/CuO nanocomposite with extracted eggshells. The structure, functional group, metal composition, bandgap, and photocatalytic activity of the nanocomposites were characterized by using X-ray diffraction, Fourier-transform infrared spectroscopy, atomic absorption spectrometry, and UV–Vis spectroscopy, respectively, in the absence and presence of eggshells. Photocatalytic degradation activities of the nanocomposites under UV light irradiation have been tested for a real sewage sample taken from Debre Berhan Textile Industry. From the results, the optimized degradation efficiency of the dye was 97.95% with 0.4 g dose of the photocatalyst, 120 min irradiation time, 120 °C temperature, and pH of 6.7. The results revealed that eggshell impregnated nanocomposite had better catalytic activity than the naked nanocomposite. This is due to the highly porous structure of eggshell biomasses and their sorption characteristics. In conclusion, when nanocomposites are supported by eggshell biomasses, they are excellent photocatalysts and can minimize the contamination of organic dyes from textile effluents.
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Alam, Mir Waqas, Hamida Azam, Nadeem R. Khalid, Sumaira Naeem, Muhammad Khalid Hussain, Amal BaQais, Mohd Farhan, Basma Souayeh, Noushi Zaidi, and Kaffayatullah Khan. "Enhanced Photocatalytic Performance of Ag3PO4/Mn-ZnO Nanocomposite for the Degradation of Tetracycline Hydrochloride." Crystals 12, no. 8 (August 17, 2022): 1156. http://dx.doi.org/10.3390/cryst12081156.
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Using sustainable photocatalysts, photocatalytic degradation has emerged as one of the viable strategies to combat water pollution through eco-friendly and cost-effective means. Visible-light-active Ag3PO4/Mn-ZnO nanocomposite photocatalysts were produced in this study using a simple hydrothermal method and varied concentrations of Ag3PO4 to Mn-ZnO ranging from 0 to 5 wt percent. X-ray diffraction, scanning electron microcopy, energy-dispersive X-ray, transmission electron microscopy, UV–visible spectroscopy, Fourier transform infra-red spectrophotometer, and photoluminescence spectroscopy were used to examine the structural, morphological, and optical properties of synthesized materials. Visible light was used to test the photocatalytic activity of produced Ag3PO4/Mn-ZnO photocatalysts for the breakdown of tetracycline (TC) hydrochloride. In comparison to the other samples, the 3% Ag3PO4/Mn-ZnO nanocomposite exhibited superior activity as a result of improved visible light absorption and suppressed charge carrier recombination. In addition, this sample demonstrated good stability of TC in an aqueous environment after five consecutive cycles. This research will enhance the scope of photocatalysis for environmental applications.
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Sin, Jin Chung, Ying Hui Chin, and Sze Mun Lam. "WO3/Nb2O5 Nanoparticles-Decorated Hierarchical Porous ZnO Microspheres for Enhanced Photocatalytic Degradation of Palm Oil Mill Effluent and Simultaneous Production of Biogas." Key Engineering Materials 821 (September 2019): 379–85. http://dx.doi.org/10.4028/www.scientific.net/kem.821.379.
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Conventionally, palm oil mill effluent (POME) was treated using open ponding system, which nevertheless long retention times and large treatment areas were required. In this report, heterogeneous photocatalysis was used to degrade the POME and simultaneously assessed the biogas formation. Characterization of the chemically prepared hierarchical porous ZnO microspheres showed that wurtzite was the predominant crystalline phase with a band gap energy of 3.22 eV. Moreover, the as-prepared ZnO were assembled by large numbers of interleaving nanosheets and formed an open porous structure. Under UV irradiation, the as-prepared ZnO demonstrated photocatalytic property on POME degradation. The WO3 and Nb2O5 decorated ZnO photocatalysts (WO3/ZnO and Nb2O5/ZnO) with improved photocatalytic performances were also prepared using a simple and rapid way. Significantly, in the presence of WO3/ZnO and Nb2O5/ZnO composites, the degradation of POME achieved 68.3% and 91.7%, respectively after 240 min irradiation. Interestingly, the assessment of the biogas formation showed that the photocatalytic reactions over Nb2O5/ZnO and WO3/ZnO composites generated higher amount of biogas products (CH4 + CO2) compared to that of ZnO. The photocatalytic enhancement was attributed to the high separation efficiency of photogenerated electron–hole pairs based on the formation of heterojunction structures between the WO3/Nb2O5 and ZnO. The observed findings also revealed that the photocatalytic technology using hierarchical WO3/ZnO and Nb2O5/ZnO composites had the potential to efficiently treat wastewater.
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Podasca, Viorica-Elena, and Mariana-Dana Damaceanu. "Photopolymerized Films with ZnO and Doped ZnO Particles Used as Efficient Photocatalysts in Malachite Green Dye Decomposition." Applied Sciences 10, no. 6 (March 12, 2020): 1954. http://dx.doi.org/10.3390/app10061954.
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Zinc oxide and zinc oxide doped with tin oxide (ZnO-SnO2) particles were synthesized and successfully incorporated into a polymeric matrix by the photopolymerization reaction in the presence of Irg819 as the photoinitiator. The obtained samples were investigated by means of XRD, ESEM/EDX, TEM, FTIR, and Raman spectroscopy. The ZnO particles were obtained in the form of rods agglomerated in flower (or star) structures with lengths of 2–4 μm and widths between 30 and 100 nm, while ZnO-SnO2 samples evolved in the form of cubes, with sides of 350 nm. The prepared composite films with ZnO and ZnO-SnO2 particles were tested in the photocatalytic degradation of malachite green (MG) dye. While the ZnO-based composite film showed a fairly high photocatalytic activity, the hybrid film containing ZnO doped with SnO2 displayed 100% photocatalytic activity after only 45 min of irradiation, being among the most efficient photocatalysts known for MG degradation. In addition, the recycling tests demonstrated that this film displayed high stability during the photocatalysis reaction since no decrease in the photocatalytic performance was noticed after the first three cycles, indicating its suitability for dyes removal and wastewater purification.
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Reddy, K. M., Chhoker Anmol, and Sharma Aditya. "Nano ZNO and surface modification ZNO with graphite oxide deposition to enhance the catalytic activity." i-manager's Journal on Material Science 9, no. 4 (2022): 9. http://dx.doi.org/10.26634/jms.9.4.18523.
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Preparation of ZnO nanoparticles and surface modification ZnO with the carbon material graphite oxide, were synthesized. The synthesized materials were characterized by PXRD, FT-IR, and UV-visible analysis. The materials show better optical and structural properties, which are beneficial in the photocatalytic degradation studies. Under light, zinc oxide and graphite oxide were used to degrade the methyl orange solution. The prepared materials by sol-gel preparation showed enhanced catalytic activity in the photocatalytic activity of methyl orange. An optimal loading content of graphite oxide was investigated. The enhanced photocatalysis was studied in detail. The study provides a promising application for the photocatalytic degradation of organic pollutants in photocatalysis. In the present work, the authors included the new novel materials of ZnO. The ZnO is modified with the surface deposits of rGO. The combined materials of semiconductor materials show a better response to light for the degradation studies. The use of such a combination is a new study and the results reflect the modification of semiconductor materials in the p-block elements such as C, N, F, P and so on for the enhanced photocatalytic applications of semiconductor mediated materials, which are widely used in photocatalysis. The PXRD analysis of ZnO and rGO shows better crystallinity in the case of ZnO, whereas after the deposition of rGO, crystallinity is lost due to the overlap of the main base material semiconductors, which explains the new catalytic and recombination effects of the materials used.
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Qiang, Xiao Dan, Feng Fu, Dan Jun Wang, and Li Guo. "Investigation of Photocatalytic Oxidative-Extraction Desulfurization of Simulation Gasoline." Advanced Materials Research 518-523 (May 2012): 750–54. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.750.
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Photocatalytic Oxidative-Extraction Desulfurization (Photo-cat-EODS) of thiophene, the main sulfur-containing compound of catalytic cracking (FCC) gasoline, has been investigated in heterogeneous photocatalysis process using WO3/ZnO composite as photocatalyst and air was used as the oxidant. Extraction process was also employ followed by the photocatalytic oxidative process to remove the oxidative products using acetonitrile as the extractant. Furthermore, orthogonal experiments method was used to optimize the processing parameters.
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Xu, Feng, Sheng Nan Sun, Yi Xin Wang, Jia Jia Cao, Zi Han Wang, Feng Ling Bian, and Hai Ning Cui. "The Photoelectric and Photocatalytic Property Study of Cu2S/ZnO Films." Applied Mechanics and Materials 271-272 (December 2012): 301–4. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.301.
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ZnO film and Cu2S/ZnO bilays on the glass substrate were fabricated by RF magnetron sputtering. We carried out the experiments by adjusting the thickness of Cu2S on ZnO layer. The performance of Cu2S/ZnO on the transparency, conduction and photocatalysis were investigated. The photocatalytic experiments showed a good photocatalytic activity for photodegradation of methyl orange.
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Титов, В. В., А. А. Лисаченко, И. Х. Акопян, М. Э. Лабзовская, and Б. В. Новиков. "Долгоживущие центры фотокатализа, создаваемые в ZnO резонансным возбуждением экситона." Физика твердого тела 61, no. 11 (2019): 2158. http://dx.doi.org/10.21883/ftt.2019.11.48422.537.
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Along with TiO_2, ZnO is the main photocatalyst for a wide class of redox reactions used to convert light energy into chemical and for environmental cleanup. It has been shown that the creation in ZnO of surface intrinsic defects in ZnO i.e. vacancies in the anionic and cationic sublattices (F-type and V-type centers) - makes it possible to create long-lived (up to 10^3 s) photocatalysis centers and thus fundamentally (tens of times) to increase the quantum yield of reactions. Slow surface states — photocatalysis centers — are created by the diffusion of electrons and holes generated during interband transitions in the volume of the photoactivated sample. However, the transfer efficiency is sharply reduced due to carrier recombination and losses when overcoming the Schottky surface barrier. In this work, In order to reduce these losses during energy transfer to the surface, we used in this work neutral energy carriers — excitons. The high (60 meV) exciton binding energy in ZnO allows it to move at room temperature without decay. The radiation loss of the exciton energy in our experiments is effectively reduced by the formation of a surface 2D structure. The results obtained confirm the high efficiency of the exciton channel for the formation of surface long-lived F and V centers of photocatalysis in the processes of oxygen photoadsorption and photodesorption, imitating the full cycle of the redox photocatalytic reaction.
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Vasilaki, Evangelia, Nikos Katsarakis, Spyros Dokianakis, and Maria Vamvakaki. "rGO Functionalized ZnO–TiO2 Core-Shell Flower-Like Architectures for Visible Light Photocatalysis." Catalysts 11, no. 3 (March 5, 2021): 332. http://dx.doi.org/10.3390/catal11030332.
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Core-shell heterostructures with a complex, flower-like morphology, comprising a ZnO core and a TiO2 shell decorated with reduced graphene oxide (rGO) sheets by hydrothermal wrapping, are reported to extend the absorption properties of the semiconductors toward the visible light range. The ternary photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, diffuse reflectance UV–Vis, and attenuated total reflectance-Fourier transform infrared spectroscopy. Its photocatalytic performance was evaluated under visible light irradiation using methylene blue dye as a model pollutant. The rGO-modified ZnO–TiO2 photocatalyst exhibited superior photoactivity compared to that of the parent ZnO–TiO2 core-shell structures, which was dependent on its graphene content. The enhanced photocatalytic response was attributed to the higher absorption in the visible light range, as well as the pronounced electron and hole separation in the ternary system.
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Paz, Diego S., Edson L. Foletto, Daniel A. Bertuol, Sérgio L. Jahn, Gabriela C. Collazzo, Syllos S. da Silva, Osvaldo Chiavone-Filho, and Claudio A. O. do Nascimento. "CuO/ZnO coupled oxide films obtained by the electrodeposition technique and their photocatalytic activity in phenol degradation under solar irradiation." Water Science and Technology 68, no. 5 (September 1, 2013): 1031–36. http://dx.doi.org/10.2166/wst.2013.345.
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CuO/ZnO coupled oxide films were electrodeposited onto an aluminum substrate and tested as photocatalysts in degradation of phenol molecules in aqueous solution under sunlight. The obtained films were characterized by X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the photocatalytic activity of films was significant, especially to coupled oxide film with a CuO/ZnO ratio equal to 0.697, which presented about 70% degradation of the aromatic molecules and 42% of total organic carbon (TOC) removal at 300 min under solar irradiation. Therefore, this work highlights the potential application of CuO/ZnO coupled oxide films obtained by electrodeposition onto aluminum substrate in the field of photocatalysis.
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Ahmad, Mukhtar, Eijaz Ahmed, Muhammad Ikram, Fezza Zafar, Niaz Ahmed Niaz, Zhanglian Hong, Abdul Hafeez, Khalid Nadeem Riaz, and Waqar Ahmed. "Preparation, Characterisation and Photocatalytic Activity of La-doped ZnO Nanopowders Synthesised using Auto-combustion." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 59, no. 1 (February 25, 2016): 1–10. http://dx.doi.org/10.52763/pjsir.phys.sci.59.1.2016.1.10.
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Nanocrystalline nanoparticles of pristine ZnO and La-doped ZnO have been synthesised usinga combustion method using various concentrations of lanthanum dopant followed by calcination for 3 hat 700 °C. The crystalline structure, chemical composition and optical characteristics have been characterisedusing X-ray diffraction (XRD), scanning electron spectroscopy (SEM) attached with energy dispersiveX-ray (EDX) spectroscopy, Brunauer Emmett Teller (BET), UV-vis. spectroscopy and photoluminescence(PL) spectroscopy. Absorption spectra showed that the absorbance increased with La-doping and the blueshift observed was due to an increase in the band gap from 3.24 to 3.27 eV. The photocatalytic activitiesof the samples prepared were evaluated using the photocatalytic degradation of methyl orange (MO) underirradiation by sunlight. The textile mill effluents containing organic matter were also irradiated with sunlightinducing photocatalysis and the chemical oxygen demand (COD) of the treated effluent were investigated.The results showed that the ZnO photocatalyst doped with 1.0 at.% lanthanum exhibited four timesenhancement in the photocatalytic activity compared to pure ZnO.
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Verma, Hemant Kumar, Mahak Vij, and K. K. Maurya. "Synthesis, Characterization and Sun Light-Driven Photocatalytic Activity of Zinc Oxide Nanostructures." Journal of Nanoscience and Nanotechnology 20, no. 6 (June 1, 2020): 3683–92. http://dx.doi.org/10.1166/jnn.2020.17679.
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Low-temperature growth of nanostructures with large yield is a basic requirement for fulfilling the demand of large-scale applications of nanomaterials. The synthesis of nanoscale materials has gained considerable attention due to their excellent properties also in photocatalysis. Catalyst and Dopant free, solar active ZnO nanostructures photocatalysts with vacancy richness were synthesized in large quantities (in grams) through the co-precipitation growth process using ZnNi2·6H2O as the zinc source at room temperature. This method has advantages such as low temperature with high yield (>8 grams per liter) at atmospheric pressure synthesis. The experimental results confirm that synthesized ZnO samples were crystallized into a wurtzite hexagonal structure. Under direct sunlight energy examined degradation of organic dye methylene blue (MB) for photocatalytic activity using ZnO nanostructures. The photocatalytic performance depends on the different defects as well as the specific surface area. After photocatalytic degradation of MB dye in 60 min under natural sunlight irradiation colorless matrix was observed. The repeatability assessments for reusability of ZnO nanostructures after photocatalytic activity was also studied and reported for degradation of organic MB dye.
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Yaqoob, Asim Ali, Nur Habibah binti Mohd Noor, Albert Serrà, and Mohamad Nasir Mohamad Ibrahim. "Advances and Challenges in Developing Efficient Graphene Oxide-Based ZnO Photocatalysts for Dye Photo-Oxidation." Nanomaterials 10, no. 5 (May 12, 2020): 932. http://dx.doi.org/10.3390/nano10050932.
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The efficient remediation of organic dyes from wastewater is increasingly valuable in water treatment technology, largely owing to the tons of hazardous chemicals currently and constantly released into rivers and seas from various industries, including the paper, pharmaceutical, textile, and dye production industries. Using solar energy as an inexhaustible source, photocatalysis ranks among the most promising wastewater treatment techniques for eliminating persistent organic pollutants and new emerging contaminants. In that context, developing efficient photocatalysts using sunlight irradiation and effectively integrating them into reactors, however, pose major challenges in the technologically relevant application of photocatalysts. As a potential solution, graphene oxide (GO)-based zinc oxide (ZnO) nanocomposites may be used together with different components (i.e., ZnO and GO-based materials) to overcome the drawbacks of ZnO photocatalysts. Indeed, mounting evidence suggests that using GO-based ZnO nanocomposites can promote light absorption, charge separation, charge transportation, and photo-oxidation of dyes. Despite such advances, viable, low-cost GO-based ZnO nanocomposite photocatalysts with sufficient efficiency, stability, and photostability remain to be developed, especially ones that can be integrated into photocatalytic reactors. This article offers a concise overview of state-of-the-art GO-based ZnO nanocomposites and the principal challenges in developing them.
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Shahmoradi, Behzad, Farzaneh Farahani, Shadi Kohzadi, Afshin Maleki, Mohammadamin Pordel, Yahya Zandsalimi, Yuxuan Gong, et al. "Application of cadmium-doped ZnO for the solar photocatalytic degradation of phenol." Water Science and Technology 79, no. 2 (January 15, 2019): 375–85. http://dx.doi.org/10.2166/wst.2019.061.
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Abstract In this study, photocatalysis of phenol was studied using Cd-ZnO nanorods, which were synthesized by a hydrothermal method. The Cd-ZnO photocatalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and Fourier transform infrared (FT-IR) and UV-Vis spectroscopy. XRD patterns exhibit diffraction peaks indexed to the hexagonal wurtzite structures with the P63mc space group. SEM images showed that the average size of the Cd-ZnO nanorods was about 90 nm. Moreover, the nanorods were not agglomerated and were well-dispersed in the aqueous medium. FT-IR analysis confirmed that a surface modifier (n-butylamine) did not add any functional groups onto the Cd-ZnO nanorods. The dopant used in this study showed reduction of the bandgap energy between valence and conduction of the photocatalyst. In addition, effect of various operational parameters including type of photocatalyst, pH, initial concentration of phenol, amount of photocatalyst, and irradiation time on the photocatalytic degradation of phenol has been investigated. The highest phenol removal was achieved using 1% Cd-ZnO for 20 mg/l phenol at pH 7, 3 g/l photocatalyst, 120 min contact time, and 0.01 mole H2O2.
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Farah Eilyana Mohamed and Wan Rafizah Wan Abdullah. "Solar Photocatalytic Efficiency of Zinc Oxide for Water Decontamination." Universiti Malaysia Terengganu Journal of Undergraduate Research 1, no. 1 (January 31, 2019): 92–102. http://dx.doi.org/10.46754/umtjur.v1i1.55.
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Solar photocatalysis is a green technology that takes advantage of sustainable solar energy for enhancing oxidation process of numerous harmful water contaminants. In this study, a custom solar driven zinc oxide (ZnO)-mediated photocatalytic system was developed and its efficiency to remove organic contaminants as well as to disinfect selected bacteria was investigated. Methylene blue (MB) dye was used as the model organic contaminant, while Escherichia coli (E.coli) was used as the model fecal coliform bacteria in contaminated water. A series of photodegradation experiments were conducted on water contaminated with either 10 mg/L of MB or ~1010 CFU/ml of E.coli. The experiments were completed under sunlight irradiation in the presence of 1 g/L of nano ZnO photocatalyst for up to 6 hours. Using a solar thermal collector, the photoreactor operated in the temperature range of 25 to 50 oC. The findings revealed that the combination of solar thermal with solar photocatalysis using ZnO intensified the degradation of MB and disinfection of E.coli. 98.08% of MB dye and 99.99% of E.coli were successfully removed from the water within the first 3 hours of treatment. Almost complete removal was eventually achieved after 6 hours of treatment. It is therefore suggested that ZnO-based solar photocatalytic system developed in this study is highly efficient at enhancing water decontamination process.
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Abdulkhair, Babiker Y., Mutaz E. Salih, Nuha Y. Elamin, A. MA Fatima, and A. Modwi. "Simplistic Synthesis and Enhanced Photocatalytic Performance of Spherical ZnO Nanoparticles Prepared from Arabinose Solution." Zeitschrift für Naturforschung A 74, no. 10 (September 25, 2019): 937–44. http://dx.doi.org/10.1515/zna-2019-0059.
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AbstractStrenuous efforts have been employed to prepare zinc oxide (ZnO) with eco-friendly methods; however, few studies have reported the fabrication of ZnO using a sustainable procedure. In this study, spherical ZnO nanoparticles were successfully fabricated for photocatalysis applications using a simple and eco-friendly method using an arabinose sugar solution. The ZnO nanoparticles with a wurtzite structure were obtained by combining zinc nitrate and arabinose in water, followed by heating, evaporation, and calcinations at different annealing temperatures. The annealed ZnO photocatalysts were characterised via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The findings revealed a hexagonal wurtzite structure and good crystallinity with crystallite size increasing from 18 to 31 nm by means of an increase in the annealing temperature. The photocatalytic performance was examined to determine the degradation of mix dye waste. The spherical ZnO nanoparticles showed mix pollutant degradation of 84 % in 25 min at 400 °C.
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Bouras, Dikra, Abla Mecif, Abdelhamid Harabi, Régis Barillé, Abdel hakim Mahdjoub, and Mourad Zaabat. "Economic and Ultrafast Photocatalytic Degradation of Orange II Using Ceramic Powders." Catalysts 11, no. 6 (June 14, 2021): 733. http://dx.doi.org/10.3390/catal11060733.
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Different percentages of CuO and ZnO were added into a local kaolin ceramic-based powder (DD3) with and without ZrO2. The modified powders were first characterized, then, a test for the photocatalytic degradation of dyes with orange II (OII) was carried out. The DD3 powders that were obtained with the addition of ZrO2, ZnO, and CuO, were prepared by two different methods and have shown a large and very fast photocatalytic activity. Discoloration ratios of about 93.6% and 100% were reached after 15 min and 45 min, for CuO and ZnO respectively. Finally, an alternative photocatalysis mechanism, based purely on chemical reaction processes, is proposed. The photocatalysis results with modified powders are compared with the results obtained with thin films, made with the same materials.
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Yu, Kai-sheng, Jian-ying Shi, Zai-li Zhang, Yong-mei Liang, and Wei Liu. "Synthesis, Characterization, and Photocatalysis of ZnO and Er-Doped ZnO." Journal of Nanomaterials 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/372951.
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ZnO and Er-doped ZnO with different molar ratios of Er/Zn were prepared using the homogeneous precipitation method. The photocatalysts prepared were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), UV-vis spectroscopy, and photoluminescence spectroscopy. The results showed that the Er-doped ZnO displayed characteristic wurtzite-type peaks in the XRD spectra. The Er-doped ZnO absorbed much more light than ZnO in the ultraviolet region. And the doping of Er into ZnO enhanced the intensity of the fluorescence emission. The degradation of methylene blue (MB) solution demonstrated that the photocatalytic activity of ZnO was significantly improved with Er doping.
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Divya, G., D. Sakthi, A. Priyadharsan, S. Boobas, and S. Sivakumar. "Anatomy of a Natural Sunlight Driven CdS/CoTiO3/ZnO Ternary Photocatalyst for Efficient Optical Properties and Removal of Reactive Orange 30." Research Journal of Chemistry and Environment 25, no. 8 (July 25, 2021): 100–109. http://dx.doi.org/10.25303/258rjce100109.
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ZnO as a promising photocatalyst has gained much attention for the removal of organic pollutants from water. However, the main drawbacks of the relatively low photocatalytic activity and high recombination rate of photoexcited electron-hole pairs restrict its potential applications. Promoting the spatial separation of photoexcited charge carriers is of paramount significance for photocatalysis because the difference in the band positions makes the potential gradient at the composite boundary. In this work, binary CdS/ZnO and CoTiO3/ZnO are first prepared by dispersion method and then decorated with ZnO particles to construct CdS/CoTiO3/ZnO ternary composites. For this reason, the CdS/CoTiO3/ZnO ternary composites was effectively designed and analyzed for the crystalline structure, light absorption, photoexcitation behavior and surface morphological properties by X-ray diffraction, diffuse reflectance UV/visible absorption spectroscopy, photoluminescence spectroscopy and scanning electron micrograph respectively. The photocatalytic activity was examined by degradation of the dye solution spectrophotometrically. The results of photocatalytic degradation indicated that the CdS/CoTiO3/ZnO ternary composites are much higher than those of bare CdS, CoTiO3, ZnO and any binary composites such as CoTiO3/ZnO and ZnO/CdS. The enhanced activity could be attributed to the drop electron transfer from CdS to ZnO to CoTiO3 through the interfacial potential gradient in the ternary hybrid conduction bands. The enhanced electron transfer of CdS/CoTiO3/ZnO ternary composites was also applicable to degrade other reactive dyes.
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Nipane, Dipak, S. R. Thakare, and N. T. Khati. "Synthesis of Novel ZnO Having Cauliflower Morphology for Photocatalytic Degradation Study." Journal of Catalysts 2013 (May 28, 2013): 1–8. http://dx.doi.org/10.1155/2013/940345.
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ZnO nanowire morphology has been widely studied due to its unique material properties and excellent performance in electronics, optics, and photonic. Recently, photocatalytic applications of ZnO nanowire are creating an increasing interest in the environmental applications. This paper presents a low-cost and ecofriendly synthesis of ZnO with cauliflower morphology and its effectiveness in photocatalysis.
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Cai, Xiaofan, Yuewu Huang, Jinzhi Hu, Shiwei Zhu, Xiaohua Tian, Kun Zhang, Guangju Ji, Yunxiao Zhang, Zhendong Fu, and Changlong Tan. "Tuning Photocatalytic Performance of Multilayer ZnO for Water Splitting by Biaxial Strain Composites." Catalysts 10, no. 10 (October 19, 2020): 1208. http://dx.doi.org/10.3390/catal10101208.
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Novel two-dimensional (2D) materials have received extensive attention in the field of photocatalysis due to their unique properties. Traditional ZnO material with wurtzite structure transforms into a stable graphite-like structure that has the characteristics of 2D material when its thickness is less than a few atomic layers. In this work, using first-principles calculations, we investigated the potential of multilayer graphite-like ZnO as a photocatalyst for water splitting. The results showed that multilayer ZnO is a series of direct bandgap semiconductors, and their band edge positions all straddle the redox potential of water. Increasing with the number of layers, the bandgap of multilayer ZnO decreased from 3.20 eV for one layer to 2.21 eV for six layers, and visible light absorption capacity was significantly enhanced. Hence, multilayer ZnO was indeed promising for photocatalytic water splitting. Furthermore, suitable biaxial tensile strain could decrease the bandgap and maintain the stable graphite-like structure at a broader thickness range. In contrast, excessive biaxial tensile strain could change the redox capacity of multilayer ZnO and prevent it from catalyzing water splitting. Our theoretical results show that six-layer ZnO under 1% biaxial strain had direct bandgap of 2.07 eV and represents the most excellent photocatalytic performance among these multilayer ZnO materials.
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Hong, Xiaodong, Xu Wang, Yang Li, Jiawei Fu, and Bing Liang. "Progress in Graphene/Metal Oxide Composite Photocatalysts for Degradation of Organic Pollutants." Catalysts 10, no. 8 (August 11, 2020): 921. http://dx.doi.org/10.3390/catal10080921.
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The sewage discharge of industrial wastewater seriously pollutes the water source and rivers, which is very harmful to the health of humans and wildlife. Among those methods for treating wastewater, photocatalysis is a sustainable and environmental-friendly technique for removing the organic pollutants with no secondary pollution. As a popular photocatalyst, graphene/metal oxide nanocomposites have been widely reported in the photocatalysis field. In this review, the recent progress of graphene/metal oxide composites including binary and ternary composites is summarized in detail. The synthesis, microstructure design, and application performance of graphene/TiO2, graphene/ZnO, graphene/SnO2, graphene/WO3, graphene/Fe2O3, and graphene/Cu2O composites are introduced firstly. Then, the synthesis, the selection of components, and the performance of various ternary composites are summarized specifically, including graphene/TiO2-, graphene/ZnO-, graphene/SnO2-, graphene/Cu2O-, graphene/FexOy-, and graphene/Bi-containing ternary composites. At last, the possible research directions of graphene/metal oxide nanocomposites are put forward. The main purpose is to provide a theoretical guidance for designing high-performance graphene/metal oxide photocatalysts for wastewater treatment.
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Kiran Kumar, A. B. V., Sanjeev Billa, Edugulla Girija Shankar, and M. C. S. Subha. "C, N dual-doped ZnO nanofoams: a potential antimicrobial agent, an efficient visible light photocatalyst and SXAS studies." Journal of Synchrotron Radiation 27, no. 1 (January 1, 2020): 90–99. http://dx.doi.org/10.1107/s160057751901364x.
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It is crucial to develop an environmentally friendly and low-cost method to treat industrial effluent that contains soluble dyes and microbes. Most of the photocatalysts have been studied using an external light source that increases the cost of the purification process of effluent. This study focuses on developing efficient solar photocatalytic nanofoams. The controlled growth of ZnO nanofoams (CNZ nanofoams) in a simple method of thermal oxidation using a soft template is reported. Prepared nanofoams are characterized using X-ray diffraction, scanning electon microscopy and synchrotron soft X-ray absorption spectroscopy. By photocatalysis studies under direct sunlight it was found that within 120 min CNZ nanofoams degraded 99% of the dye. In addition, antimicrobial studies of multi-drug-resistant E. Fergusonii isolated from wastewater was carried out. These antimicrobial results showed a good inhibition zone, indicating that prepared nanofoams are both an effective solar photocatalyst and an antimicrobial agent.
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Kyu Kim, Jong, and Luiza Cintra Campos. "Adsorption and photocatalytic degradation of metaldehyde in aqueous solution." Water Supply 15, no. 3 (January 3, 2015): 533–40. http://dx.doi.org/10.2166/ws.2015.002.
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Metaldehyde is best known as the main constituent of slug pellets. This organic compound has been found in relatively high levels in both surface and underground water. While many water treatment processes do not work with metaldehyde degradation, a photocatalytic degradation process has been proved to have a significant effect on metaldehyde stability. Nanosized ZnO/laponite composite (NZLC) was used as a photocatalyst in this investigation of metaldehyde degradation. The reactions were carried out in a ultraviolet C (UVC) lamp fitted batch reactor by considering the following parameters: initial metaldehyde concentration, pH of solution, and light intensity. A comparison of degradation efficiency between photolysis, photocatalysis, and adsorptive ability on NZLC indicated that the latter had the highest efficiency. Furthermore, higher metaldehyde degradation was observed as the initial concentration decreased. However, the fastest metaldehyde degradation rate in heterogeneous photocatalysis was obtained when pH values were greater than 7.0. Consequently, the findings suggest that the removal of metaldehyde by adsorption and photocatalytic degradation using NZLC under UV irradiation was a hybrid reaction process (i.e. photolysis, adsorption, and photocatalysis).
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Grigorjeva, L., J. Rikveilis, J. Grabis, Dz Jankovica, C. Monty, D. Millers, and K. Smits. "Photocatalitic Properties of Tio2 and ZnO Nanopowders / Tio2 un Zno Nanopulveru Fotokatalitiskās Īpašības." Latvian Journal of Physics and Technical Sciences 50, no. 4 (August 1, 2013): 48–55. http://dx.doi.org/10.2478/lpts-2013-0025.
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Abstract Photocatalytic activity of TiO2 and ZnO nanopowders is studied depending on the morphology, grain sizes and method of synthesizing. Photocatalysis of the prepared powders was evaluated by degradation of the methylene blue aqueous solution. Absorbance spectra (190-100 nm) were measured during exposure of the solution to UV light. The relationships between the photocatalytic activity and the particle size, crystal polymorph phases and grain morphology were analyzed. The photocatalytic activity of prepared TiO2 nanopowders has been found to depend of the anatase-to-rutile phase ratio. Comparison is given for the photocatalytic activity of ZnO nanopowders prepared by sol-gel and solar physical vapour deposition (SPVD) methods