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1
Prakash, Jai. "Mechanistic Insights into Graphene Oxide Driven Photocatalysis as Co-Catalyst and Sole Catalyst in Degradation of Organic Dye Pollutants". Photochem 2, nr 3 (17.08.2022): 651–71. http://dx.doi.org/10.3390/photochem2030043.
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Photocatalysis is a promising route to utilize sunlight, which has been potentially used to solve energy as well as environmental problems with an emphasis on fundamental understanding and technological applications in society. Semiconductors are excellent photocatalysts but often show less efficient activities due to the fast recombination of photogenerated charge carriers and very slow kinetics of surface photochemical reactions. However, recent advancements show promising strategies to improve their photocatalytic activities, including surface modifications using suitable co-catalysts and the development of novel efficient photocatalysts. Graphene oxide (GO) is one of such nanomaterials which shows multifarious roles in photocatalysis with a great potential to act as an independent solar-driven sole photocatalyst. In this minireview, the photochemistry of GO has been discussed in view of its multifarious roles/mechanisms in improving the photocatalytic activity of metal oxide semiconductors, plasmonic nanomaterials, and also their nanocomposites. In addition, recent advancements and applications of such GO-based photocatalysts in photocatalytic degradation of organic dye pollutants, including engineering of GO as the sole photocatalyst, have been discussed. Furthermore, the challenges and future prospects for the development of GO-based photocatalysts are discussed.
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Chen, De Qiang, Yang Li i Yi Qun Chen. "Preparation of Graphene and γ-Fe2O3 Doped Titanium Dioxide and its Photocatalytic Properties". Applied Mechanics and Materials 295-298 (luty 2013): 447–51. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.447.
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In this paper graphene is used to improve absorption rate of nano-titanium dioxide under visible light, meanwhile titanium dioxide is doped with superparamagnetism nano-powder of γ-Fe2O3 to modify the recovery of the photocatalyst. Gradually the increasing content of grapheme promotes the removal efficiency and correspondingly. Excitation condition is reduced and the photocatalysis property under visible light is improved and recycle rate of the titanium dioxide is effective promoted after the dispose. The effect of photocatalytic degradation of methylene blue is used to evaluate the photocatalytic activity. The methylene blue degradation rate raised from 53.4% to 85.9% with the increasing graphene load from 5% to 20% under visible light. The degradation efficiency of methylene blue decreased to 15% without the graphene load. The recovery rate of the photocatalyst can achieve 95% above. Graphene oxide works as the electron acceptor and photosensitizer to efficiently enhance the dye photodecomposition.
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Nasir, Amara, Sadia Khalid, Tariq Yasin i Anca Mazare. "A Review on the Progress and Future of TiO2/Graphene Photocatalysts". Energies 15, nr 17 (27.08.2022): 6248. http://dx.doi.org/10.3390/en15176248.
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TiO2 is seen as a low cost, well-known photocatalyst; nevertheless, its sluggish charge kinetics does limit its applications. To overcome this aspect, one of the recent approaches is the use of its composites with graphene to enhance its photoactivity. Graphene-based materials (nanosheets, quantum dots, etc.) allow for attachment with TiO2 nanostructures, resulting in synergistic properties and thus increasing the functionality of the resulting composite. The current review aims to present the marked progress recently achieved in the use of TiO2/graphene composites in the field of photocatalysis. In this respect, we highlight the progress and insights in TiO2 and graphene composites in photocatalysis, including the basic mechanism of photocatalysis, the possible design strategies of the composites and an overview of how to characterize the graphene in the mixed composites. The use of composites in photocatalysis has also been reviewed, in which the recent literature has opened up more questions related to the reliability, potential, repeatability and connection of photocatalytic mechanisms with the resulting composites. TiO2/graphene-based composites can be a green light in the future of photocatalysis, targeting pollution remediation, energy generation, etc.
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Sánchez, Luis A., Brian E. Huayta, Pierre G. Ramos i 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, nr 1 (1.02.2022): 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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Albero, Josep, Diego Mateo i Hermenegildo García. "Graphene-Based Materials as Efficient Photocatalysts for Water Splitting". Molecules 24, nr 5 (5.03.2019): 906. http://dx.doi.org/10.3390/molecules24050906.
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Photocatalysis has been proposed as one of the most promising approaches for solar fuel production. Among the photocatalysts studied for water splitting, graphene and related materials have recently emerged as attractive candidates due to their striking properties and sustainable production when obtained from biomass wastes. In most of the cases reported so far, graphene has been typically used as additive to enhance its photocatalytic activity of semiconductor materials as consequence of the improved charge separation and visible light harvesting. However, graphene-based materials have demonstrated also intrinsic photocatalytic activity towards solar fuels production, and more specifically for water splitting. The photocatalytic activity of graphene derives from defects generated during synthesis or their introduction through post-synthetic treatments. In this short review, we aim to summarize the most representative examples of graphene based photocatalysts and the different approaches carried out in order to improve the photocatalytic activity towards water splitting. It will be presented that the introduction of defects in the graphenic lattice as well as the incorporation of small amounts of metal or metal oxide nanoparticles on the graphene surface improve the photocatalytic activity of graphene. What is more, a simple one-step preparation method has demonstrated to provide crystal orientation to the nanoparticles strongly grafted on graphene resulting in remarkable photocatalytic properties. These two features, crystal orientation and strong grafting, have been identified as a general methodology to further enhance the photocatalytic activity in graphenebased materials for water splitting. Finally, future prospects in this filed will be also commented.
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Hong, Xiaodong, Xu Wang, Yang Li, Jiawei Fu i Bing Liang. "Progress in Graphene/Metal Oxide Composite Photocatalysts for Degradation of Organic Pollutants". Catalysts 10, nr 8 (11.08.2020): 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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Johar, Muhammad Ali, Rana Arslan Afzal, Abdulrahman Ali Alazba i 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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Cai, Tingwei, Ying Ding i Lihui Xu. "Synthesis of flower-like CuS/graphene aerogels for dye wastewater treatment". Functional Materials Letters 12, nr 02 (kwiecień 2019): 1950002. http://dx.doi.org/10.1142/s1793604719500024.
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A novel visible-light flower-like CuS/graphene aerogels (CuS/GAs) photocatalyst has been synthesized via two-step solvothermal method. The CuS/GAs show outstanding synergies of adsorption and photocatalysis for anionic–cationic dyes degradation, which is attributed to unique network structure and excellent photoelectric properties of GAs. The high degradation ratio of Methyl orange and Methylene blue by synergy are 92% and 99.36%, which are about 4.1 and 3.2 times of that for pure CuS. The flower-like CuS/graphene aerogels resolve the low adsorption saturation problem of GAs and improve the photocatalytic performance of CuS, indicating CuS/GAs could be a promising photocatalyst for wastewater treatment.
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Yang, Zanhe, Siqi Zhou, Xiangyu Feng, Nannan Wang, Oluwafunmilola Ola i Yanqiu Zhu. "Recent Progress in Multifunctional Graphene-Based Nanocomposites for Photocatalysis and Electrocatalysis Application". Nanomaterials 13, nr 13 (7.07.2023): 2028. http://dx.doi.org/10.3390/nano13132028.
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The global energy shortage and environmental degradation are two major issues of concern in today’s society. The production of renewable energy and the treatment of pollutants are currently the mainstream research directions in the field of photocatalysis. In addition, over the last decade or so, graphene (GR) has been widely used in photocatalysis due to its unique physical and chemical properties, such as its large light-absorption range, high adsorption capacity, large specific surface area, and excellent electronic conductivity. Here, we first introduce the unique properties of graphene, such as its high specific surface area, chemical stability, etc. Then, the basic principles of photocatalytic hydrolysis, pollutant degradation, and the photocatalytic reduction of CO2 are summarized. We then give an overview of the optimization strategies for graphene-based photocatalysis and the latest advances in its application. Finally, we present challenges and perspectives for graphene-based applications in this field in light of recent developments.
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Chen, Yanling, i Xue Bai. "A Review on Quantum Dots Modified g-C3N4-Based Photocatalysts with Improved Photocatalytic Activity". Catalysts 10, nr 1 (20.01.2020): 142. http://dx.doi.org/10.3390/catal10010142.
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In the 21st century, the development of sustainable energy and advanced technologies to cope with energy shortages and environmental pollution has become vital. Semiconductor photocatalysis is a promising technology that can directly convert solar energy to chemical energy and is extensively used for its environmentally-friendly properties. In the field of photocatalysis, graphitic carbon nitride (g-C3N4) has obtained increasing interest due to its unique physicochemical properties. Therefore, numerous researchers have attempted to integrate quantum dots (QDs) with g-C3N4 to optimize the photocatalytic activity. In this review, recent progress in combining g-C3N4 with QDs for synthesizing new photocatalysts was introduced. The methods of QDs/g-C3N4-based photocatalysts synthesis are summarized. Recent studies assessing the application of photocatalytic performance and mechanism of modification of g-C3N4 with carbon quantum dots (CQDs), graphene quantum dots (GQDs), and g-C3N4 QDs are herein discussed. Lastly, challenges and future perspectives of QDs modified g-C3N4-based photocatalysts in photocatalytic applications are discussed. We hope that this review will provide a valuable overview and insight for the promotion of applications of QDs modified g-C3N4 based-photocatalysts.
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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 i 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, nr 4 (11.04.2022): 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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Xu, Zhi Ying, Xin Gang Wang, Yang Bo Liu, Wei Sheng Ma i Ze Qin Mo. "Study on Preparation and Decontamination Properties of Hybrid-Photocatalysis Based on Graphene and TiO2". Advanced Materials Research 1092-1093 (marzec 2015): 988–91. http://dx.doi.org/10.4028/www.scientific.net/amr.1092-1093.988.
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The hybrid-photocatalyst was successfully prepared by compositing graphene and TiO2 in this thesis. The properties of the hybrid-photocatalyst was stydited by XRD, SEM. The hotocatalytic activity of the hybrid-photocatalyst was evaluated by decolorization of acid yellow dye solution under visible light irradiation. The result shows that the main phase of the hybrid-photocatalyst is antase TiO2. The effects of different titanium carbon ratio, photocatalysis time, catalyst dosage and pH on the photocatalytic for acid yellow dye are discussed. Under the conditions that titanium carbon ratio 100:50, the photocatalytic time 120 min, catalyst dosing concentration 0.1g / L and the optimum pH 8, the treatment of methyl orange dye is the best.
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Sayury Miyashiro, Carolina, i Safia Hamoudi. "Palladium and Graphene Oxide Doped ZnO for Aqueous Acetamiprid Degradation under Visible Light". Catalysts 12, nr 7 (28.06.2022): 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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Lee, Jun-Cheol, Anantha-Iyengar Gopalan, Gopalan Sai-Anand, Kwang-Pill Lee i Wha-Jung Kim. "Preparation of Visible Light Photocatalytic Graphene Embedded Rutile Titanium(IV) Oxide Composite Nanowires and Enhanced NOx Removal". Catalysts 9, nr 2 (11.02.2019): 170. http://dx.doi.org/10.3390/catal9020170.
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The quest for developing highly efficient TiO2-based photocatalysts is continuing and, in particular, evolving a new strategy is an important aspect in this regard. In general, much effort has been devoted to the anatase TiO2 modifications, despite there being only a few recent studies on rutile TiO2 (rTiO2). To the best of our knowledge, studies on the preparation and characterization of the photocatalysts based on the intentional inclusion of graphene (G) into rTiO2 nanostructures have not been reported yet. Herein, we develop a new type of TiO2-based photocatalyst comprising of G included pure rTiO2 nanowire (abbreviated as rTiO2(G) NW) with enhanced visible light absorption capability. To prepare rTiO2(G) NW, the G incorporated titanate electrospun fibers were obtained by electrospinning and subsequently heat treated at various temperatures (500 to 800 °C). Electrospinning conditions were optimized for producing good quality rTiO2(G) NW. The rTiO2(G) NW and their corresponding samples were characterized by appropriate techniques such as X-ray diffraction (XRD), scanning electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy to ascertain their material characteristics. XRD results show that the lattice strain occurs upon inclusion of G. We present here the first observation of an apparent bandgap lowering because of the G inclusion into TiO2 NW. While anatase TiO2 NW exhibited poor visible light photocatalysis towards NOx removal, the rTiO2(G) NW photocatalyst witnessed a significantly enhanced (~67%) photocatalytic performance as compared to anatase TiO2(G) NW. We concluded that the inclusion of G into rTiO2 nanostructures enhances the visible light photoactivity. A plausible mechanism for photocatalysis is suggested.
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Vasilaki, Evangelia, Nikos Katsarakis, Spyros Dokianakis i Maria Vamvakaki. "rGO Functionalized ZnO–TiO2 Core-Shell Flower-Like Architectures for Visible Light Photocatalysis". Catalysts 11, nr 3 (5.03.2021): 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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Aguilera Mandujano, A., i J. Serrato Rodriguez. "Synthesis and characterization of titania/graphene nanocomposite for application in photocatalysis". Revista Mexicana de Física 66, nr 5 Sept-Oct (1.09.2020): 610. http://dx.doi.org/10.31349/revmexfis.66.610.
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Titanium dioxide has been extensively investigated as a photocatalyst for water purification, presenting limitations such as recombination of electron-hole pairs generated by photons. The titania / graphene nanocomposites are promising materials to overcome these limitations due to the high specific area of graphene and unique electronic properties. In this work, an anatase-graphene nanocomposite was synthesized by a simple mixture assisted by ultrasound. Graphene was obtained by electrochemical exfoliation of graphite using the electrolysis technique. On the other hand, anatase was synthesized using the sol gel method. The obtained graphene, anatase and the nanocomposite material, were characterized with the X-ray diffraction technique (DRX), scanning electron microscopy (MEB) and transmission electron microscopy (MET). Using Raman spectroscopy, it was possible to verify that the graphite exfoliated correctly producing few layer-graphene. The lamellar nano-structure of the exfoliated graphite has crystallographic planes characteristic of graphite, graphene and graphene oxide. The presence of the anatase phase is shown in the diffraction spectrum of titania. The images obtained with SEM and TEM of the graphene sample show a layered lamellar structure and the TiO2 images show agglomerates of ellipsoidal nanoparticles. Obtained titania nanoparticles have a size of about 6 nm. Band gap value for such extremely low particle size nanocomposite is around 3.6 eV and presumably corresponds to the TiO2 (anatase) phase that completely surrounds the graphene. A nanocomposite model based on HRTEM observations is proposed. Considering the graphene electrical properties and the photocatalytic properties of TiO2, this nanocomposite promises to have applications in photocatalysis.
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Sanchez Tobon, Camilo, Ivana Panžić, Arijeta Bafti, Gordana Matijašić, Davor Ljubas i Lidija Ćurković. "Rapid Microwave-Assisted Synthesis of N/TiO2/rGO Nanoparticles for the Photocatalytic Degradation of Pharmaceuticals". Nanomaterials 12, nr 22 (11.11.2022): 3975. http://dx.doi.org/10.3390/nano12223975.
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Nanocomposites comprising nitrogen-doped TiO2 and reduced graphene oxide (N/TiO2/rGO), with different rGO loading qualities, were prepared by a cost-effective microwave-assisted synthesis method. The synthesized materials were broadly characterized by Raman spectroscopy, X-ray diffraction (XRD), infrared spectroscopy (FTIR), photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), electron microscopy (SEM-EDS), and nitrogen adsorption/desorption isotherms. Anatase was the only crystalline phase observed for all synthesized materials. The rGO loading did not affect the morphological properties, but it positively influenced the photocatalytic activity of the nanocomposite materials, especially at low rGO loading. Photocatalysts were evaluated via the degradation of specific organic micropollutant (OMP) pharmaceuticals: ciprofloxacin (CIP), diclofenac (DCF), and salicylic acid (SA), under different radiation sources: ultraviolet A (UVA), solar light simulator (SLS), blue visible light (BVL) and cold visible light (CVL). CIP and SA were removed effectively via the synergy of adsorption and photocatalysis, while DCF degradation was achieved solely by photocatalysis. After implementing scavenger agents, photocatalytic degradation processes mainly depended on the specific pollutant type, while irradiation sources barely defined the photocatalytic mechanism. On the other hand, changes in irradiation intensity significantly influenced the photolysis process, while photocatalysis was slightly affected, indicating that irradiation spectra are more relevant than intensity.
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Kumar, Suneel, Ashish Kumar, Ashish Bahuguna, Vipul Sharma i Venkata Krishnan. "Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications". Beilstein Journal of Nanotechnology 8 (3.08.2017): 1571–600. http://dx.doi.org/10.3762/bjnano.8.159.
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In the pursuit towards the use of sunlight as a sustainable source for energy generation and environmental remediation, photocatalytic water splitting and photocatalytic pollutant degradation have recently gained significant importance. Research in this field is aimed at solving the global energy crisis and environmental issues in an ecologically-friendly way by using two of the most abundant natural resources, namely sunlight and water. Over the past few years, carbon-based nanocomposites, particularly graphene and graphitic carbon nitride, have attracted much attention as interesting materials in this field. Due to their unique chemical and physical properties, carbon-based nanocomposites have made a substantial contribution towards the generation of clean, renewable and viable forms of energy from light-based water splitting and pollutant removal. This review article provides a comprehensive overview of the recent research progress in the field of energy generation and environmental remediation using two-dimensional carbon-based nanocomposites. It begins with a brief introduction to the field, basic principles of photocatalytic water splitting for energy generation and environmental remediation, followed by the properties of carbon-based nanocomposites. Then, the development of various graphene-based nanocomposites for the above-mentioned applications is presented, wherein graphene plays different roles, including electron acceptor/transporter, cocatalyst, photocatalyst and photosensitizer. Subsequently, the development of different graphitic carbon nitride-based nanocomposites as photocatalysts for energy and environmental applications is discussed in detail. This review concludes by highlighting the advantages and challenges involved in the use of two-dimensional carbon-based nanocomposites for photocatalysis. Finally, the future perspectives of research in this field are also briefly mentioned.
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Usman, Muhammad, Muhammad Humayun, Syed Shaheen Shah, Habib Ullah, Asif A. Tahir, Abbas Khan i Habib Ullah. "Bismuth-Graphene Nanohybrids: Synthesis, Reaction Mechanisms, and Photocatalytic Applications—A Review". Energies 14, nr 8 (19.04.2021): 2281. http://dx.doi.org/10.3390/en14082281.
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Photocatalysis is a classical solution to energy conversion and environmental pollution control problems. In photocatalysis, the development and exploration of new visible light catalysts and their synthesis and modification strategies are crucial. It is also essential to understand the mechanism of these reactions in the various reaction media. Recently, bismuth and graphene’s unique geometrical and electronic properties have attracted considerable attention in photocatalysis. This review summarizes bismuth-graphene nanohybrids’ synthetic processes with various design considerations, fundamental mechanisms of action, heterogeneous photocatalysis, benefits, and challenges. Some key applications in energy conversion and environmental pollution control are discussed, such as CO2 reduction, water splitting, pollutant degradation, disinfection, and organic transformations. The detailed perspective of bismuth-graphene nanohybrids’ applications in various research fields presented herein should be of equal interest to academic and industrial scientists.
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Li, Jiquan, Youyan Wang, Huan Ling, Ye Qiu, Jia Lou, Xu Hou, Sankar Parsad Bag, Jie Wang, Huaping Wu i Guozhong Chai. "Significant Enhancement of the Visible Light Photocatalytic Properties in 3D BiFeO3/Graphene Composites". Nanomaterials 9, nr 1 (5.01.2019): 65. http://dx.doi.org/10.3390/nano9010065.
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Bismuth ferrite (BiFeO3, BFO) submicron cubes and 3D BFO/graphene composite materials were synthesized by a simple hydrothermal process. The crystallization processes of the 3D BFO/graphene composites with different graphene oxide (GO) concentrations were studied for their visible light photocatalytic properties. Compared to the single BFO submicron cubes, 3D BFO/graphene composites have greatly improved photocatalytic activity. A high photocatalytic performance is obtained at a GO concentration of 3 mg/mL, with the degradation rate of methylene blue (MB) dye reaching up to 92% in 140 min. The enhancement of photocatalytic activity can be attributed to the large specific surface area and 3D architecture of 3D composites, which provide more transport paths to effectively improve the separation rate of photo-generated electrons and holes. Therefore, 3D BFO/graphene composites have a broad prospect of application in the field of photocatalysis.
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Gardner, Henry. "Preparation of Graphene/WO3 Nanocomposite and Its Application in Photocatalytic Degradation". Applied and Computational Engineering 1, nr 1 (5.05.2022): 37–42. http://dx.doi.org/10.54254/ace.2022005.
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Graphene/semiconductor nanocomposites were prepared by hydrothermal method, and the photocatalytic degradation performance of the composite was investigated. The mechanism of photocatalysis is proposed and analysed. It is believed that graphene can effectively improve the separation efficiency of photogenerated electron-hole pairs, improve the physical structure and light absorption performance of the catalyst, thereby improving the photocatalytic activity and degradation efficiency. Finally, the possible development trend of this kind of materials in the future was proposed.
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Shabestari, Marjan E., Juan Baselga i Olga Martin. "Photocatalytic Behavior of Supported Copper Double Salt: The Role of Graphene Oxide". Journal of Chemistry 2022 (12.05.2022): 1–9. http://dx.doi.org/10.1155/2022/7844259.
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The design of a photocatalyst that may work efficiently with sunlight is a fundamental concern to fight against environmental pollution and electrochemical hydrogen storage devices. In this work, it has been found that the green microwave-assisted decoration of graphene by copper double salt (DS) enhances visible sunlight photocatalysis efficiency. Nanohybrids of graphene oxide decorated with Cu(I) and Cu(II) oxides and copper hydroxy nitrate double salt were selected as photocatalysts for the degradation of rhodamine B in aqueous solution to study the effect of the graphene oxide support. The photodegradation process followed a pseudo–first-order kinetics for the bare catalysts, but the supported catalysts were best fitted to the Langmuir-Hinshelwood model. Supported systems were more efficient in terms of turnover and apparent rate constants. Diffuse reflectance spectroscopy with the use of Kubelka-Munk function allowed to measure bandgap energies. It was found that the absorption edge was reduced about 30% for the supported systems.
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Altendji, Khaoula, i Safia Hamoudi. "Efficient Photocatalytic Degradation of Aqueous Atrazine over Graphene-Promoted g-C3N4 Nanosheets". Catalysts 13, nr 9 (1.09.2023): 1265. http://dx.doi.org/10.3390/catal13091265.
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Atrazine is a systemic herbicide widely used in weed control. In recent years, it has been largely detected in surface and groundwater in several locations all over the world. Photocatalysis is a green and sustainable technology with huge application prospects in pollution control and the degradation of organic water pollutants. In this work, photodegradation of aqueous atrazine was investigated over pristine graphitic carbon nitride (g-C3N4) synthesized via urea pyrolysis and graphene/g-C3N4 composite synthesized via the in situ growth method involving direct deposition of g-C3N4 nanosheets on the graphene surface. The obtained photocatalysts were characterized using transmission and scanning electron microscopy, Fourier-transformed infrared spectroscopy, UV-visible spectroscopy, photoluminescence spectroscopy, X-ray diffraction, and surface area measurements. It was demonstrated that the composite material exhibited remarkable photocatalytic properties for the efficient degradation of aqueous atrazine under visible light at ambient temperature. After 5 h of reaction, atrazine conversion reached 100% in the presence of graphene/g-C3N4 composite, while the pristine g-C3N4 allowed 40% conversion under the same conditions, thus demonstrating the positive effect of graphene on the photocatalytic activity of g-C3N4. Moreover, graphene/g-C3N4 was shown to keep its activity even when it was recycled five times, thus proving its stability and its potential to be used at the industrial scale.
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Sass, Mouele i Ross. "Nano Silver-Iron-Reduced Graphene Oxide Modified Titanium Dioxide Photocatalytic Remediation System for Organic Dye". Environments 6, nr 9 (9.09.2019): 106. http://dx.doi.org/10.3390/environments6090106.
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The organic water contaminant, methyl orange contaminant (M.O), has shown a hazardous increase in our water systems over the past few years due to its increasing demand in industrial processes. The photocatalytic degradation of the commercial dye was studied through the application of modified TiO2 composite catalysts in aqueous solution under artificial irradiation. The improvement of photocatalytic activity is strongly affected by the various functional groups emerging in the organic substances. In this work, the effect of both silver-iron and silver-iron-reduced graphene oxide-modified titanium dioxide towards M.O remediation as a cost-effective photocatalyst was investigated. We confirmed that the novel AgFe functionalized TiO2 catalyst (AgFe-TiO2) showed more superior remediation activity than the reduced graphene oxide (rGO)-modified TiO2 due to the decreased band gap from 3.02 eV–2.5 eV with increased photocatalysis. Based on the spectroscopic and microscopic results, the enhanced photocatalytic degradation of M.O dye was induced by its enhanced surface area, electron diffusion, and the reduction of photo-generated electron-hole pairs’ recombination.
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Wu, Guosong, Qiuping Shen, Houlin Yu, Tingyu Zhao, Congda Lu i Aiping Liu. "Reduced graphene oxide encapsulated Cu2O with controlled crystallographic facets for enhanced visible-light photocatalytic degradation". Functional Materials Letters 10, nr 04 (sierpień 2017): 1750034. http://dx.doi.org/10.1142/s1793604717500345.
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The Cu2O/reduced graphene oxide (Cu2O/rGO) composites with effective crystallographic facet controlling of Cu2O crystals were fabricated through a simple one-step wet chemistry method. The crystallographic facet-dependent photocatalytic performance of Cu2O was confirmed, favoring the cuboctahedral Cu2O with {100} and {111} facets and a better photocatalytic activity when compared to cubic and octahedral ones. This was attributed to the slight difference of surface energy between {100} and {111} facets which served as a driving force to promote the separation of photogenerated electron–hole pairs. Moreover, the introduction of two-dimensional rGO sheets could accelerate the transfer of photogenerated electrons from Cu2O to rGO, which further promoted the separation of photogenerated electron–hole pairs and the degradation of methyl orange (MO) under visible-light irradiation. The cuboctahedral Cu2O/rGO composite exhibited a superb photocatalytic performance with the degradation percentage of MO about 97.6% after one periodic photocatalysis due to the synergistic effect of cuboctahedral Cu2O and rGO sheets, foreboding its potential application as photocatalyst.
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Dharwadkar, Sripriya, Linlong Yu i Gopal Achari. "Photocatalytic Degradation of Sulfolane Using a LED-Based Photocatalytic Treatment System". Catalysts 11, nr 5 (12.05.2021): 624. http://dx.doi.org/10.3390/catal11050624.
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Sulfolane is an emerging industrial pollutant detected in the environments near many oil and gas plants in North America. So far, numerous advanced oxidation processes have been investigated to treat sulfolane in aqueous media. However, there is only a few papers that discuss the degradation of sulfolane using photocatalysis. In this study, photocatalytic degradation of sulfolane using titanium dioxide (TiO2) and reduced graphene oxide TiO2 composite (RGO-TiO2) in a light-emitting diode (LED) photoreactor was investigated. The impact of different waters (ultrapure water, tap water, and groundwater) and type of irradiation (UVA-LED and mercury lamp) on photocatalytic degradation of sulfolane were also studied. In addition, a reusability test was conducted for the photocatalyst to examine the degradation of sulfolane in three consecutive cycles with new batches of sulfolane-contaminated water. The results show that LED-based photocatalysis was effective in degrading sulfolane in waters even after three photocatalytic cycles. UVA-LEDs displayed more efficient use of photon energy when compared with the mercury lamps as they have a narrow emission spectrum coinciding with the absorption of TiO2. The combination of UVA-LED and TiO2 yielded better performance than UVA-LED and RGO-TiO2 for the degradation of sulfolane. Much lower sulfolane degradation rates were observed in tap water and groundwater than ultrapure water.
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Wang, Dong Fang, Da Chen, Guang Xing Ping, Chao Wang, Hai Zhen Chen i Kang Ying Shu. "Preparation and Photocatalysis Properties of TiO2/Graphene Nanocomposites". Advanced Materials Research 430-432 (styczeń 2012): 1005–8. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1005.
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In this work, a novel photocatalyst with excellent photocatalytic activities was developed by the combination of TiO2 with graphene oxide (GO). GO was firstly prepared by the chemical oxidation of graphite through Hummers method and the subsequent dispersion and exfoliation in water. Then, GO and P25 nanoparticles (commercial TiO2) were used as raw materials to synthesize TiO2/graphene (TiO2/GE) nanocomposites by using a one-step solvothermal method. TEM images clearly showed that TiO2 nanomaterials (the size of about 15~20 nm) were distributed well onto the two-dimensional (2D) graphene sheets, indicating the formation of TiO2/GE nanocomposites. XRD results indicated that TiO2/GE nanocomposites exhibited TiO2 crystalline phase structure. Meanwhile, it was demonstrated from the methylene blue (MB) photodegradation results that TiO2/GE nanocomposites possessed excellent photocatalytic activities with potential applications.
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Wang, Wan Jun, Jimmy C. Yu i Po Keung Wong. "Photocatalysts for Solar-Induced Water Disinfection: New Developments and Opportunities". Materials Science Forum 734 (grudzień 2012): 63–89. http://dx.doi.org/10.4028/www.scientific.net/msf.734.63.
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Recent years have seen a surge of interest in the application of solar energy for water disinfection by using nanostructured photocatalysts elaborately designed and fabricated. Photocatalysis has its unique advantage for utilizing sunlight to drive the disinfection process. The highly reactive oxygen species (ROS) serve as the main oxidants and are capable of inactivating microorganisms, including viruses, bacteria, spores and protozoa. This chapter presents an overview of current research activities that center on the preparation, characterization and application of highly efficient photocatalysts for water disinfection under both UV and visible light irradiation. It is organized into two major parts. One is the development of TiO2-based photocatalysts including surface noble metal modified, ion doped, dye-sensitized, and composite TiO2. The other part is the introduction of new types of photocatalysts and advanced technologies that have recently fascinated the scientific community. Particular attention is given to the pioneering fields such as graphene-based photocatalysts, plasmonic-metal nanostructures and naturally occurring photocatalysts. Finally, we conclude with a discussion of what major advancements are needed to move the field of photocatalytic water disinfection forward.
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Yadav, Anuja A., Yuvaraj M. Hunge, Seok-Won Kang, Akira Fujishima i Chiaki Terashima. "Enhanced Photocatalytic Degradation Activity Using the V2O5/RGO Composite". Nanomaterials 13, nr 2 (13.01.2023): 338. http://dx.doi.org/10.3390/nano13020338.
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Semiconductor-based photocatalyst materials played an important role in the degradation of organic compounds in recent years. Photocatalysis is a simple, cost-effective, and environmentally friendly process for degrading organic compounds. In this work, vanadium pentoxide (V2O5) and V2O5/RGO (reduced graphene oxide) composite were synthesized by a hydrothermal method. The prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Raman spectroscopy, and UV-Vis spectroscopic analysis, etc. Raman analysis shows the occurrence of RGO characteristic peaks in the composite and different vibrational modes of V2O5. The band gap of flake-shaped V2O5 is reduced and its light absorption capacity is enhanced by making its composite with RGO. The photocatalytic degradation of methylene blue (MB) was studied using both V2O5 and V2O5/RGO composite photocatalyst materials. The V2O5/RGO composite exhibits a superior photocatalytic performance to V2O5. Both catalyst and light play an important role in the degradation process.
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Ferreira, Maria Eliana Camargo, Lara de Souza Soletti, Eduarda Gameleira Bernardino, Heloise Beatriz Quesada, Francielli Gasparotto, Rosângela Bergamasco i Natália Ueda Yamaguchi. "Synergistic Mechanism of Photocatalysis and Photo-Fenton by Manganese Ferrite and Graphene Nanocomposite Supported on Wood Ash with Real Sunlight Irradiation". Catalysts 12, nr 7 (7.07.2022): 745. http://dx.doi.org/10.3390/catal12070745.
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The present research aimed to evaluate the photocatalytic activity of reduced graphene oxide and manganese ferrite nanocomposite supported on eucalyptus wood ash waste (WA) from industrial boilers, for the decolorization of methylene blue (MB) solutions, using sunlight as an irradiation source. For this, the photocatalyst named MnFe2O4-G@WA was synthesized by a solvothermal method and characterized by analyzes of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller and zeta potential. Firstly, the photocatalyst was evaluated for photocatalytic decolorization of MB under different reaction conditions. Then, the influence of pH, photocatalyst dose and H2O2 was evaluated. MnFe2O4-G@WA showed 94% of efficiency for photocatalytic decolorization of MB under operating conditions of solar irradiation, 0.25 g/L of catalyst, 300 mg/L of H2O2. The proposed degradation reaction mechanism suggested that the photodegradation of MB was through a synergistic mechanism of photocatalysis and photo-Fenton reactions, with the combined action of the three materials used. The data adjusted to the first order kinetics from the Langmuir–Hinshelwood model. In addition, MnFe2O4-G@WA showed high stability, maintaining its efficiency above 90% after 5 cycles. The results indicated that the nanophotocatalyst is a potential technology for the decolorization of MB solutions.
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Li, Yue-Hua, Zi-Rong Tang i Yi-Jun Xu. "Multifunctional graphene-based composite photocatalysts oriented by multifaced roles of graphene in photocatalysis". Chinese Journal of Catalysis 43, nr 3 (marzec 2022): 708–30. http://dx.doi.org/10.1016/s1872-2067(21)63871-8.
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Bokare, Anuja, Sowbaranigha Chinnusamy i Folarin Erogbogbo. "TiO2-Graphene Quantum Dots Nanocomposites for Photocatalysis in Energy and Biomedical Applications". Catalysts 11, nr 3 (28.02.2021): 319. http://dx.doi.org/10.3390/catal11030319.
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The focus of current research in material science has shifted from “less efficient” single-component nanomaterials to the superior-performance, next-generation, multifunctional nanocomposites. TiO2 is a widely used benchmark photocatalyst with unique physicochemical properties. However, the large bandgap and massive recombination of photogenerated charge carriers limit its overall photocatalytic efficiency. When TiO2 nanoparticles are modified with graphene quantum dots (GQDs), some significant improvements can be achieved in terms of (i) broadening the light absorption wavelengths, (ii) design of active reaction sites, and (iii) control of the electron-hole (e−-h+) recombination. Accordingly, TiO2-GQDs nanocomposites exhibit promising multifunctionalities in a wide range of fields including, but not limited to, energy, biomedical aids, electronics, and flexible wearable sensors. This review presents some important aspects of TiO2-GQDs nanocomposites as photocatalysts in energy and biomedical applications. These include: (1) structural formulations and synthesis methods of TiO2-GQDs nanocomposites; (2) discourse about the mechanism behind the overall higher photoactivities of these nanocomposites; (3) various characterization techniques which can be used to judge the photocatalytic performance of these nanocomposites, and (4) the application of these nanocomposites in biomedical and energy conversion devices. Although some objectives have been achieved, new challenges still exist and hinder the widespread application of these nanocomposites. These challenges are briefly discussed in the Future Scope section of this review.
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Zhu, Zhen, Bo-Xun Jiang, Ren-Jang Wu, Cheng-Liang Huang i You Chang. "Photoreduction of CO2 into CH4 Using Novel Composite of Triangular Silver Nanoplates on Graphene-BiVO4". Catalysts 12, nr 7 (7.07.2022): 750. http://dx.doi.org/10.3390/catal12070750.
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Plasmonic photocatalysis, combing noble metal nanoparticles (NMNPs) with semiconductors, has been widely studied and proven to perform better than pure semiconductors. The plasmonic effects are mainly based on the localized surface plasmon resonance (LSPR) of NMNPs. The LSPR wavelength depends on several parameters, such as size, shape, the surrounding media, and the interdistance of the NMNPs. In this study, graphene-modified plate-like BiVO4 composites, combined with silver nanoplates (AgNPts), were successfully prepared and used as a photocatalyst for CO2 photoconversion. Triangular silver nanoplates (TAgNPts), icosahedral silver nanoparticles (I-AgNPs), and decahedra silver nanoparticles (D-AgNPs) were synthesized using photochemical methods and introduced to the nanocomposites to compare the shape-dependent plasmonic effect. Among them, T-AgNPts/graphene/BiVO4 exhibited the highest photoreduction efficiency of CO2 to CH4, at 18.1 μmolg−1h−1, which is 5.03 times higher than that of pure BiVO4 under the irradiation of a Hg lamp. A possible CO2 photoreduction mechanism was proposed to explain the synergetic effect of each component in TAgNPts/graphene/BiVO4. This high efficiency reveals the importance of considering the compositions of photocatalysts for converting CO2 to solar fuels.
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Shaalan, Nagih M., Mohamed Rashad i Chawki Awada. "Synergistic Effect of NiO-Ga2O2-Graphene Heterostructures on Congo Red Photodegradation in Water". Separations 9, nr 8 (2.08.2022): 201. http://dx.doi.org/10.3390/separations9080201.
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We studied the effect of the mixed phase of nickel oxide–gallium oxide–graphene (NiO-Ga2O2/G) heterostructure nanocomposite on the photocatalytic degradation of Congo red dye. The effect was investigated based on NiO-Ga2O2 junction, NiO-graphene, and Ga2O2-graphene contacts. The laser-induced graphene was embedded into NiO and NiO-Ga2O2. Raman spectra confirmed the fabrication of disordered graphene and the mixed phase between the oxides and graphene. HRTEM showed that very fine nanoparticles for both NiO and Ga2O2 with a size of ~7–10 nm were synthesized. Elemental compositional expressed the formation mixed phase. The effect of graphene content was investigated at 2 and 10% wt with NiO and the heterojunction of NiO-Ga2O2. The photocurrent studies was measured of these nanocomposite film deposited on two interdigitated gold electrodes, biased by 5.0 V and irradiated by the UV source. The results of photocatalysis measurements indicated an improvement occurred upon the heterojunction between Ga2O2 and NiO, however, a dramatic improvement was observed with the addition of graphene of 10%. The results expressed that the ternary phase of p-NiO/n-Ga2O2/graphene is promising in the photocatalytic application toward Congo red decomposition.
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Rashad, Mohamed, Saloua Helali, Nagih M. Shaalan, Aishah E. Albalawi, Naifa S. Alatawi, Bassam Al-Faqiri, Mohammed M. Al-Belwi i Abdulrhman M. Alsharari. "Dual Studies of Photo Degradation and Adsorptions of Congo Red in Wastewater on Graphene–Copper Oxide Heterostructures". Materials 16, nr 10 (14.05.2023): 3721. http://dx.doi.org/10.3390/ma16103721.
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This work comprehensively studies both the photocatalytic degradation and the adsorption process of Congo red dye on the surface of a mixed-phase copper oxide–graphene heterostructure nanocomposite. Laser-induced pristine graphene and graphene doped with different CuO concentrations were used to study these effects. Raman spectra showed a shift in the D and G bands of the graphene due to incorporating copper phases into the laser-induced graphene. The XRD confirmed that the laser beam was able to reduce the CuO phase to Cu2O and Cu phases, which were embedded into the graphene. The results elucidate incorporating Cu2O molecules and atoms into the graphene lattice. The production of disordered graphene and the mixed phases of oxides and graphene were validated by the Raman spectra. It is noted from the spectra that the D site changed significantly after the addition of doping, which indicates the incorporation of Cu2O in the graphene. The impact of the graphene content was examined with 0.5, 1.0, and 2.0 mL of CuO. The findings of the photocatalysis and adsorption studies showed an improvement in the heterojunction of copper oxide and graphene, but a significant improvement was noticed with the addition of graphene with CuO. The outcomes demonstrated the compound’s potential for photocatalytic use in the degradation of Congo red.
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Pelosato, Renato, Isabella Bolognino, Francesca Fontana i Isabella Natali Sora. "Applications of Heterogeneous Photocatalysis to the Degradation of Oxytetracycline in Water: A Review". Molecules 27, nr 9 (24.04.2022): 2743. http://dx.doi.org/10.3390/molecules27092743.
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Photocatalytic processes are being studied extensively as potential advanced wastewater treatments for the removal of pharmaceuticals, pesticides and other recalcitrant micropollutants from the effluents of conventional wastewater treatment plants (WWTPs). Oxytetracycline (OTC) is a widespread antibiotic which is frequently detected in surface water bodies as a recalcitrant and persistent micropollutant. This review provides an update on advances in heterogeneous photocatalysis for the degradation of OTC in water under UV light, sunlight and visible-light irradiation. Photocatalysts based on pure semiconducting oxides are rarely used, due to the problem of rapid recombination of electron–hole pairs. To overcome this issue, a good strategy could be the coupling of two different semiconducting compounds with different conduction and valence bands. Several methods are described to enhance the performances of catalysts, such as doping of the oxide with metal and/or non-metal elements, surface functionalization, composites and nano-heterojunction. Furthermore, a discussion on non-oxidic photocatalysts is briefly provided, focusing on the application of graphene-based nanocomposites for the effective treatment of OTC.
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Gao, Weiyin, Minqiang Wang, Chenxin Ran i Le Li. "Facile one-pot synthesis of MoS2 quantum dots–graphene–TiO2 composites for highly enhanced photocatalytic properties". Chemical Communications 51, nr 9 (2015): 1709–12. http://dx.doi.org/10.1039/c4cc08984g.
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We reported a simple one-pot solvothermal approach to fabricate MoS2 quantum dots (QDs)–graphene–TiO2 (MGT) composite photocatalyst with significant improved photocatalysis property, which is caused by the increased charge separation, visible-light absorbance, specific surface area and reaction sites upon the introduction of MoS2 QDs.
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Razak, Sharin, Ong Soon Hin i Raihan Hamzah. "Photocatalytic Degradation of Methylene Blue by TiO2- Graphene Composite". Solid State Phenomena 317 (maj 2021): 257–62. http://dx.doi.org/10.4028/www.scientific.net/ssp.317.257.
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Inappropriate treatments of discharge wastewater from textile industries effluents with high concentrated dye are dangerous to the human and aquatic life due to the carcinogenic effect and chemical toxicity. Therefore, the usage of TiO2 photocatalysis in water treatment has shown a significant impact on the degradation of dye into less carcinogenic and toxicity of the water. Interestingly, the addition of graphene oxide into TiO2 system showed better photocatalytic efficiency of dye degradation as compared toTiO2 photocatalyst alone due to a sufficient amount of radicals supply by the graphene oxide. The oxide radicals reacted with the dye radicals and eliminate the possibility of any chances of recombination of photons and electrons during the photodegradation process. These immobilized graphene/TiO2 films were coated onto the glass substrate under the influence of polymeric polyvinyl aceatate/ polyvinyl chloride (PVA/PVC) mixture act as a binder. The adhesion strength of the immobilized system was fixed at ratio 1:0.025 of PVA/PVC binders. As a result, the immobilized system showed a high degradation rate of methylene blue dye due to the improvement of charge separation and also good adhesion property and sustainability of the film during continuous wastewater treatment.
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Yaqoob, Asim Ali, Nur Habibah binti Mohd Noor, Albert Serrà i Mohamad Nasir Mohamad Ibrahim. "Advances and Challenges in Developing Efficient Graphene Oxide-Based ZnO Photocatalysts for Dye Photo-Oxidation". Nanomaterials 10, nr 5 (12.05.2020): 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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Zhou, Chaocun, Yanming Yang, Yueshuai Zhu, Juanjuan Ma, Jinlin Long, Rusheng Yuan, Zhengxin Ding, Zhaohui Li i Chao Xu. "A graphene-hidden structure with diminished light shielding effect: more efficient graphene-involved composite photocatalysts". Catalysis Science & Technology 8, nr 18 (2018): 4734–40. http://dx.doi.org/10.1039/c8cy00954f.
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Li, Xin, Jiaguo Yu, S. Wageh, Ahmed A. Al-Ghamdi i Jun Xie. "Graphene in Photocatalysis: A Review". Small 12, nr 48 (2.11.2016): 6640–96. http://dx.doi.org/10.1002/smll.201600382.
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Mandal, Soumen, Srinivas Mallapur, Madhusudana Reddy, Jitendra Kumar Singh, Dong-Eun Lee i Taejoon Park. "An Overview on Graphene-Metal Oxide Semiconductor Nanocomposite: A Promising Platform for Visible Light Photocatalytic Activity for the Treatment of Various Pollutants in Aqueous Medium". Molecules 25, nr 22 (17.11.2020): 5380. http://dx.doi.org/10.3390/molecules25225380.
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Graphene is one of the most favorite materials for materials science research owing to its distinctive chemical and physical properties, such as superior conductivity, extremely larger specific surface area, and good mechanical/chemical stability with the flexible monolayer structure. Graphene is considered as a supreme matrix and electron arbitrator of semiconductor nanoparticles for environmental pollution remediation. The present review looks at the recent progress on the graphene-based metal oxide and ternary composites for photocatalysis application, especially for the application of the environmental remediation. The challenges and perspectives of emerging graphene-based metal oxide nanocomposites for photocatalysis are also discussed.
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Kuo, Cheng-Chi, i Chun-Hu Chen. "Graphene thickness-controlled photocatalysis and surface enhanced Raman scattering". Nanoscale 6, nr 21 (2014): 12805–13. http://dx.doi.org/10.1039/c4nr03877k.
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Li, Ting, Tian Tian, Fangyuan Chen, Xiang Liu i Xiaohua Zhao. "Pd Nanoparticles Incorporated Within a Zr-Based Metal–Organic Framework/Reduced Graphene Oxide Multifunctional Composite for Efficient Visible-Light-Promoted Benzyl Alcohol Oxidation". Australian Journal of Chemistry 72, nr 5 (2019): 334. http://dx.doi.org/10.1071/ch18387.
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Metal–organic frameworks (MOFs) in photocatalysis oxidation reactions have been arousing great interest because of their unique properties. Zr-based MOFs (mainly 1,4-dicarboxybenzene MOF (UiO-66)) appear to be very attractive candidates. In this study, a Pd@UiO-66/reduced graphene oxide (rGO) nanocomposite was successfully prepared via a facile solvothermal method and was characterised by several techniques, including field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, and photoluminescence (PL) spectroscopy. Subsequently, the as-obtained Pd@UiO-66/rGO composite was used as a photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde with O2 under visible light irradiation (>420nm); it exhibited superior photocatalytic activity due to the synergistic effect of coupling Pd nanoparticles (NPs) with UiO-66 and rGO. Importantly, the Pd@UiO-66/rGO composite showed high stability and considerable recyclability to preserve most of its initial photocatalytic activity after five cycles of the oxidation reaction.
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Al Marzouqi, Faisal, i Rengaraj Selvaraj. "Surface Plasmon Resonance Induced Photocatalysis in 2D/2D Graphene/g-C3N4 Heterostructure for Enhanced Degradation of Amine-Based Pharmaceuticals under Solar Light Illumination". Catalysts 13, nr 3 (10.03.2023): 560. http://dx.doi.org/10.3390/catal13030560.
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Pharmaceuticals, especially amine-based pharmaceuticals, such as nizatidine and ranitidine, contaminate water and resist water treatment. Here, different amounts of graphene sheets are coupled with g-C3N4 nanosheets (wt% ratio of 0.5, 1, 3 and 5 wt% of graphene) to verify the effect of surface plasmon resonance introduced to the g-C3N4 material. The synthesized materials were systematically examined by advanced analytical techniques. The prepared photocatalysts were used for the degradation of amine-based pharmaceuticals (nizatidine and ranitidine). The results show that by introducing only 3 wt% graphene to g-C3N4, the absorption ability in the visible and near-infrared regions dramatically enhanced. The absorption in the visible range was 50 times higher when compared to the pure sample. These absorption features suggest that the surfaces of the carbon nitride sheet are covered by the graphene nanosheet, which would effectively apply the LSPR properties for catalytic determinations. The enhancement in visible light absorption in the composite was confirmed by PL analysis, which showed greater inhibition of the electron-hole recombination process. The XRD showed a decrease in the (002) plan due to the presence of graphene, which prevents further stacking of carbon nitride layers. Accordingly, the Gr/g-C3N4 composite samples exhibited an enhancement in the photocatalytic performance, specifically for the 5% Gr/g-C3N4 sample, and close to 85% degradation was achieved within 20 min under solar irradiation. Therefore, applying the Gr/g-C3N4 for the degradation of a pharmaceutical can be taken into consideration as an alternative method for the removal of such pollutants during the water treatment process. This enhancement can be attributed to surface plasmon resonance-induced photocatalysis in a 2D/2D graphene/g-C3N4 heterostructure.
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Albiter, Elim, Aura S. Merlano, Elizabeth Rojas, José M. Barrera-Andrade, Ángel Salazar i Miguel A. Valenzuela. "Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review". Journal of Composites Science 5, nr 1 (25.12.2020): 4. http://dx.doi.org/10.3390/jcs5010004.
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ZnO is an exciting material for photocatalysis applications due to its high activity, easy accessibility of raw materials, low production costs, and nontoxic. Several ZnO nano and microstructures can be obtained, such as nanoparticles, nanorods, micro flowers, microspheres, among others, depending on the preparation method and conditions. ZnO is a wide bandgap semiconductor presenting massive recombination of the generated charge carriers, limiting its photocatalytic efficiency and stability. It is common to mix it with metal, metal oxide, sulfides, polymers, and nanocarbon-based materials to improve its photocatalytic behavior. Therefore, ZnO–nanocarbon composites formation has been a viable alternative that leads to new, more active, and stable photocatalytic systems. Mainly, graphene is a well-known two-dimensional material, which could be an excellent candidate to hybridize with ZnO due to its excellent physical and chemical properties (e.g., high specific surface area, optical transmittance, and thermal conductivity, among others). This review analyses ZnO–graphene nanocomposites’ recent advances, addressing the synthesis methods and the resulting structural, morphological, optical, and electronic properties. Moreover, we examine the ZnO–graphene composites’ role in the photocatalytic degradation of organic/inorganic pollutants.
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Ding, Zhe, Jianjun Liang, Wentao Zhang, Wei Wang, Rongyue Geng, Yun Wang, Ping Li i Qiaohui Fan. "Efficiency and active sites of the synergetic sorption and photocatalysis in Cr(vi) decontamination on a 3D oxidized graphene ribbon framework". Journal of Materials Chemistry A 8, nr 22 (2020): 11362–69. http://dx.doi.org/10.1039/d0ta01847c.
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A 3D framework based on graphene oxide ribbons promises unique advantages in Cr(vi) remediation via the synergetic effect of sorption and photocatalysis. The active sites of sorption and photocatalysis are disclosed at a molecular level.
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Kumar, Sanjay, Himanshi, Jyoti Prakash, Ankit Verma, Suman, Rohit Jasrotia, Abhishek Kandwal i in. "A Review on Properties and Environmental Applications of Graphene and Its Derivative-Based Composites". Catalysts 13, nr 1 (4.01.2023): 111. http://dx.doi.org/10.3390/catal13010111.
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Graphene-based materials have gained a lot of scientific interest in the research era of modern technology, which can be quite flexible. Graphene has become popular as a potential material for the manufacture of a wide range of technologies due to its remarkable electrical, mechanical, and optical traits. Due to these excellent characteristics, the derivatives of graphene can be functionalized in various applications including environmental, medical, electronic, defence applications, and many more. In this review paper, we discussed the different synthesis methods for the extraction of graphene and its derivatives. The different traits of graphene and its derivatives such as structural, mechanical, and optical were also discussed. An extensive literature review on the application of graphene-based composites is presented in this work. We also outlined graphene’s potential in the realm of environmental purification through different techniques such as filtration, adsorption, and photocatalysis. Lastly, the challenges and opportunities of graphene and its derivatives for advanced environmental applications were reported.
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Memisoglu, Gorkem, Raghavan Chinnambedu Murugesan, Joseba Zubia i Aleksey G. Rozhin. "Graphene Nanocomposite Membranes: Fabrication and Water Treatment Applications". Membranes 13, nr 2 (22.01.2023): 145. http://dx.doi.org/10.3390/membranes13020145.
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Graphene, a two-dimensional hexagonal honeycomb carbon structure, is widely used in membrane technologies thanks to its unique optical, electrical, mechanical, thermal, chemical and photoelectric properties. The light weight, mechanical strength, anti-bacterial effect, and pollution-adsorption properties of graphene membranes are valuable in water treatment studies. Incorporation of nanoparticles like carbon nanotubes (CNTs) and metal oxide into the graphene filtering nanocomposite membrane structure can provide an improved photocatalysis process in a water treatment system. With the rapid development of graphene nanocomposites and graphene nanocomposite membrane-based acoustically supported filtering systems, including CNTs and visible-light active metal oxide photocatalyst, it is necessary to develop the researches of sustainable and environmentally friendly applications that can lead to new and groundbreaking water treatment systems. In this review, characteristic properties of graphene and graphene nanocomposites are examined, various methods for the synthesis and dispersion processes of graphene, CNTs, metal oxide and polymer nanocomposites and membrane fabrication and characterization techniques are discussed in details with using literature reports and our laboratory experimental results. Recent membrane developments in water treatment applications and graphene-based membranes are reviewed, and the current challenges and future prospects of membrane technology are discussed.
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Kong, Kelvert, Ying Weng, Weng Hoong Lam i Sin Yuan Lai. "Environmental Footprint Assessment of Methylene Blue Photodegradation using Graphene-based Titanium Dioxide". Bulletin of Chemical Reaction Engineering & Catalysis 18, nr 1 (8.03.2023): 103–17. http://dx.doi.org/10.9767/bcrec.17450.
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To date, photocatalysis has received much attention in terms of the degradation of organic pollutants in wastewater. Various studies have shown that graphene-based photocatalysts are one of the impressive options owing to their intriguing features, including high surface area, good conductivity, low recombination rate of electron-hole pair, and fast charge separation and transfer. However, the environmental impacts of the photocatalysts synthesis and their photodegradation activity remain unclear. Thus, this report aims to identify the environmental impacts associated with the photodegradation of methylene blue (MB) over reduced graphene oxide/titanium oxide photocatalyst (TiO2/rGO) using Life Cycle Assessment (LCA). The life cycle impacts were assessed using ReCiPe 2016 v1.1 midpoint method, Hierachist version in Gabi software. A cradle-to-gate approach and a functional unit of 1 kg TiO2/rGOwere adopted in the study. Several important parameters, such as the solvent type (ultrapure water, ethanol, and isopropanol), with/without silver ion doping, and visible light power consumption (150, 300, and 500 W) were evaluated in this study. In terms of the selection of solvent, ultrapure water is certainly a better choice since it contributed the least negative impact on the environment. Furthermore, it is not advisable to dope the photocatalyst with silver ions since the increment in performance is insufficient to offset the environmental impact that it caused. The results of different power of visible light for MB degradation showed that the minimum power level, 150 W, could give a comparable photodegradation efficiency and better environmental impacts compared to higher power light sources. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).