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Reduction of a clear graphene oxide solution using sodium dithionite. Graphene flakes appear "out of nothing". Observation in regular intervals for altogether 45 minutes
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In this study, KH550-modified graphene/ODA-PMDA-NTADA copolyimide nanocomposites were successfully made in an organic medium using KH-550 chemically modified reduced graphene oxide (rGO-NH 2 ) as a multi-functional comonomer combinied with commercially available ODA, PMDA, and NTADA monomers, and their dispersive, morphological, thermal, viscous, c...
Citations
... In 0.5 mol/L (NH 4 ) 2 SO 4 solution, GO was obtained by passing 8~15 V direct current from graphite and cathode platinum electrodes used as anode for 1-4 hours [8]. GO was synthesized as a result of passing an electric current of 20 V for 20 min from graphite electrodes immersed in KClO 3 solution with a concentration of 0.5 mol/L [9]. ...
Studies on the synthesis of graphene oxide in ammonium carbonate solution by electrochemical method were conducted. During the synthesis of graphene oxide, a partial reduction of graphene oxide was observed as a result of stirring the solution. The composition of graphene oxide was analyzed using UV-and ATR-FTIR spectroscopy and quantum chemical calculation methods. As a result of the analysis, it was found that the graphene oxide contains hydroxyl, carboxyl, methylene, methyl, and ether groups connecting aromatic rings. Absorption in the 264 nm region, according to the UV spectrum, indicates a partial reduction of graphene oxide. It is important to carry out the synthesis process in a cold solution of ammonium carbonate because when the solution is warm, the hydrolysis of the salt increases. Ammonia and carbon dioxide gases are released in the hydrolysis process. This research work demonstrates a clean separation of graphene oxide in ammonium carbonate solution.
... The initially created thick slurry solution then progressively changed into a brown solution as a result of constant stirring and heating, adding support to the previously reported effective synthesis of graphene oxide. 45 Characterization of Graphene Oxide by FT-IR Figure-1 displays the outcome of FT-IR characterization. The stretching vibrations of the O−H bond (hydroxyl group) is seen as a prominent band at 3204 cm -1 in the IR spectra of materials that resemble graphene oxide. ...
Due to the increase in bacterial resistance, the presence of antibiotic residues in ambient water is becoming a serious problem. In order to stop antibiotic-related water contamination, graphene oxide has been extensively employed as an advanced adsorbent. In this study, cassava peel was utilized to create graphene oxide, which was then applied as an adsorbent to remove tetracycline. The modified Hummers technique was used to produce graphene oxide, along with an oxidizing agent. Studies have been done on graphene oxide characterization and adsorption process optimization. According to the study, tetracycline removal was best accomplished under settings that included an adsorbent mass of 20 mg, an antibiotic concentration of 10 ppm, a pH of 5, and a contact period of 10 minutes. The adsorbent substance has shown promise in removing tetracycline from aqueous environments.
... In 0.5 mol/L (NH4)2SO4 solution, a direct current with a voltage of 8~15 V was passed in 1-4 hours through the graphite and cathode platinum electrodes used as an anode, and GO was obtained [10]. GO was synthesized as a result of passing an electric current of 20 V for 20 minutes through graphite electrodes immersed in KClO3 solution with a concentration of 0.5 mol/L [11]. ...
At present, many studies are being conducted on obtaining graphene oxide from graphite by chemical and electrochemical methods. However, the purification of graphene oxide obtained by these methods from the reaction mixture has certain complications. In our study, the possibility of obtaining and purifying graphene oxide of ammonium carbonate by electrochemical method was shown. The optimal conditions for obtaining graphene oxide at different concentrations of ammonium carbonate solution and different electric voltages were studied. The results showed that in ammonium carbonate solution, with a concentration of 1 mol/L, was found to be an optimal condition for obtaining a relatively productive amount of graphene oxide by passing an electric current from graphite electrodes at a voltage of 6 V.
... Although permanganate is a strong oxidizing agent, manganese heptoxide (Mn2O7) is a real active reagent that is built up during the reaction of permanganate and sulfuric acid. The temperature needs to be controlled during the synthesis, because manganese heptoxide tends to react explosively when exposed to temperature at 55 ℃ [12]. ...
The synthesis of graphene oxide-coated mesoporous silica (MS_GO) with the template surfactant (Cetyltrimethylammonium Bromide) CTAB has been carried out. The effect of combining mesoporous silica and graphene oxide was studied by knowing the bonds, functional groups and crystalline structures. Functional groups C=O and C=C were formed at wave numbers 1,722, 1,617 and 1,647 cm−1, respectively, as a characteristic of GO compounds. XRD data showed that MS_GO has a more amorphous structure than graphite and GO due to the incorporation of silica onto the graphene oxide surface. The MS_GO synthesis was also applied as an adsorbent for methylene blue dye in water. The adsorption results showed that MS_GO was more effective than pure GO. The percent adorption efficiency (R %) of MS_GO against 10 ppm methylene blue was 93.1 % while that of pure GO was 91.5 %. The addition of mesoporous silica to graphene oxide makes MS_GO adsorbent more effective in adsorption dyes than pure GO, this is supported by the larger total surface area of BET MS_GO was 161.066 m2·g−1, while that of pure GO was 103.818 m2·g−1. HIGHLIGHTS Preparation of graphene oxide from graphite by the modified hummer method Mesoporous silica is synthesized with Graphene Oxide (GO) and occupies between GO layers in the GO interlayer space CTAB is used as a template and forms pores in the synthesis of layered Mesoporous Silica-Graphene Oxide (MS_GO) Graphene Oxide-Coated Mesoporous Silica will be applied for adsorption of methylene blue dye in water. The adsorption efficiency (% R) of GO against methylene blue is lower than % R of MS_GO against methylene blue GRAPHICAL ABSTRACT
... The poisonous and explosive gas evolved from NaNO 3 , and the explosion danger emerging from the usage of KMnO 4 in H 2 SO 4 , are two of the risks unique to the Hummers' method; 1) Once NaNO 3 is added, it can be dangerous as it releases poisonous and dangerous gases, such as NO 2 and N 2 O 4 and 2) KMnO 4 in H 2 SO 4 creates a hazardous heptoxide (Schedy et al., 2018), whereby, at temperatures over 55 • C, manganese heptoxide (Mn 2 O 7 ) reacts and combusts with almost any organic compound. What's more, at temperatures higher than 95 • C, potassium heptoxide may ignite. ...
... What's more, at temperatures higher than 95 • C, potassium heptoxide may ignite. The oxidation process itself is very exothermic and may reach 60 • C without cooling (Schedy et al., 2018). ...
As a result of its carbon-dense structure and renewable nature, lignocellulosic biomass has emerged as a novel source for the production of graphene. At sufficient heat, biopolymers (cellulose, hemicellulose, and lignin) can be disintegrated into three-dimensional turbostratic crystallites, consisting of partially defective carbon sheets of aromatic rings (graphite-like material) via pyrolysis, where it may serve as a precursor in graphene synthesis. There are several techniques employed for graphene synthesis from lignocellulosic biomass; carbonization, graphitization, hydrothermal carbonization, chemical activation, chemical blowing technique, template-based confinement, mechanical and chemical exfoliation, and carbon growth via chemical vapor deposition. This review offers an insight into lignocellulosic biomass compositions and those aforementioned mechanisms to produce graphene-based materials, which cover various parameters and properties outcomes. A summary of their applications prospect, environmental impacts, economic concerns and production challenges is also presented.
... This clearly shows that MoSe 2 /MXene/C has the smallest high-frequency concave semicircle and the smaller interfacial resistance. The proposed design strategy provides a broad prospect for the development of more useful PIBs electrode materials [250] . ...
... The inset shows the corresponding equivalent circuits for data fitting, where Rct, Zw, RF, CPE and RS represent contact resistance, constant-phase element, electrolyte resistance, charge-transfer resistance and Warburg ion-diffusion resistance, respectively. Reproduced with permission from Ref.[250] (Copyright 2019, American Chemical Society). ...
Energy storage devices such as batteries hold great importance for society, owing to their high energy density, environmental benignity and low cost. However, critical issues related to their performance and safety still need to be resolved. The periodic table of elements is pivotal to chemistry, physics, biology and engineering and represents a remarkable scientific breakthrough that sheds light on the fundamental laws of nature. Here, we provide an overview of the role of the most prominent elements, including s-block, p-block, transition and inner-transition metals, as electrode materials for lithium-ion battery systems regarding their perspective applications and fundamental properties. We also outline hybrid materials, such as MXenes, transition metal oxides, alloys and graphene oxide. Finally, the challenges and prospects of each element and their derivatives and hybrids for future battery systems are discussed, which may provide guidance towards green, low-cost, versatile and sustainable energy storage devices.
... There are a number of methods for synthesis of 2D materials, as listed in Figure 3a, including: Hummer's method [48], micromechanical cleavage [1,49,50], liquid exfoliation [51] assisted by ion intercalation [52][53][54][55] and mechanical force [47,[56][57][58][59], oxidation assisted liquid exfoliation [17,49,60], chemical vapor deposition [61][62][63][64][65], wet chemical synthesis method [66][67][68][69], electrochemical exfoliation [70][71][72][73][74], ball milling [51,75], etching-assisted exfoliation etc. [76][77][78]. All these methods can be grouped in two major classes of top-down and bottom-up approaches. ...
... All these methods can be grouped in two major classes of top-down and bottom-up approaches. There are a number of methods for synthesis of 2D materials, as listed in Figure 3a, including: Hummer's method [48], micromechanical cleavage [1,49,50], liquid exfoliation [51] assisted by ion intercalation [52][53][54][55] and mechanical force [47,[56][57][58][59], oxidation assisted liquid exfoliation [17,49,60], chemical vapor deposition [61][62][63][64][65], wet chemical synthesis method [66][67][68][69], electrochemical exfoliation [70][71][72][73][74], ball milling [51,75], etching-assisted exfoliation etc. [76][77][78]. All these methods can be grouped in two major classes of top-down and bottom-up approaches. ...
In contrast to zero-dimensional (0D), one-dimensional (1D), and even their bulk equivalents, in two-dimensional (2D) layered materials, charge carriers are confined across thickness and are empowered to move across the planes. The features of 2D structures, such as quantum confinement, high absorption coefficient, high surface-to-volume ratio, and tunable bandgap, make them an encouraging contestant in various fields such as electronics, energy storage, catalysis, etc. In this review, we provide a gentle introduction to the 2D family, then a brief description of transition metal dichalcogenides (TMDCs), mainly focusing on MoS2, followed by the crystal structure and synthesis of MoS2, and finally wet chemistry methods. Later on, applications of MoS2 in dye-sensitized, organic, and perovskite solar cells are discussed. MoS2 has impressive optoelectronic properties; due to the fact of its tunable work function, it can be used as a transport layer, buffer layer, and as an absorber layer in heterojunction solar cells. A power conversion efficiency (PCE) of 8.40% as an absorber and 13.3% as carrier transfer layer have been reported for MoS2-based organic and perovskite solar cells, respectively. Moreover, MoS2 is a potential replacement for the platinum counter electrode in dye-sensitized solar cells with a PCE of 7.50%. This review also highlights the incorporation of MoS2 in silicon-based heterostructures where graphene/MoS2/n-Si-based heterojunction solar cell devices exhibit a PCE of 11.1%.
... It is recognised as the thinnest material of today's world with no bandgap, which allows it to be a wonderful candidate to use in environmental applications. Based on unique chaarcterstics, graphene has become the "miracle material" of the 21st century (Schedy et al., 2018). Besides this, it has attracted great interest due to its excellent electrical conductivity (5000 W m À1 K À1 ) (Garcia-Gallastegui et al., 2012), fascinating mechanical properties, large surface area (~2600 m 2 g À1 ), and low coefficient of thermal expansion (Allen, 2009;Geim and Opportunities, 2009;Zhang et al., 2005). ...
Functional properties of two-dimensional (2D) nano-hybrid materials have received much attention in advanced research and technology due to exponential need of green energy, clean water and pollution free environment. Nowadays, it is a demanding apprehension to develop advanced stratigies for the synthesis of nano-hybrid multifunctional materials such as graphene oxide supported layered double hydroxides (GO/LDHs) by employing different chemical routes with extraordinary properties that can lead to novel technologies for identifying and addressing the current global environmental challenges. Starting with paradigm graphene doped with other 2D materials including layered metal hydroxides (LMHs), mixed metal oxides (MMOs), metal nitrides (MXenes) and metal carbides have gradually emerged as potential hybrid nanomaterials for the removal of environmental pollutants. The current review highlights the ongoing advances of hybrid LDHs-supported nanomaterials in various fields. Association of LDHs with carbon-based nanomaterials (graphene/graphene oxide, carbon quantum dots, carbon nanotubes/nanofibers) exposed that these nanocomposite materials have outstanding environmental applications owing to their distinctive combination of architectural properties, exfoliation, and nanoarchitectural topological transformation features. GO/LDHs have many potential applications in wastewater treatment, adsorption and separation of toxic gases from environment, environmental sensors and catalysts. Sooner, the LDHs-supported nanomaterials are anticipated to open an innovative eco-friendly way for their possible applicability in environmental systems.
