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. 相似文献
In the fabrication of flexible devices, highly ordered nanoscale texturing, such as semiconductor metal oxide nanorod arrays on flexible substrates, is critical for optimal performance. Use of transparent conducting films, metallic films, and polymer substrates is limited by mechanical brittleness, chemical and thermal instability, or low electrical conductivity, low melting point, and so on. A simple and general nanocrystal-seed-directed hydrothermal route has now been developed for large-scale growth of nanorod arrays of various semiconductor metal oxides (MO), including TiO(2), ZnO, MnO(2), CuO, and ZrO(2) on both sides of flexible graphene (G) sheets to form sandwichlike MO/G/MO heterostructures. The TiO(2)/G/TiO(2) heterostructures have much higher photocatalytic activity than TiO(2) nanorods, with a photocatalytic degradation rate of methylene blue that is four times faster than that of the TiO(2) nanorods, and are thus promising candidates for photocatalytic decontamination. 相似文献
Liquid-crystalline blue phases (BPs) are stable only for very narrow temperature range between the isotropic and the chiral nematic phase that severely hinders their applicability. Herein, the aminoazobenzol group was chemically grafted onto epoxy group of graphene oxide (GO) via addition reaction. Successful grafting of aminoazobenzol group was confirmed using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), UV–vis absorption spectra and thermogravimetric analysis (TGA). The resultant aminoazobenzol group–modified GO sheets, which is reduced (RGO-Az), were easily redispersable in common organic solvents or liquid crystals (LCs). By doping different contents of RGO-Az, nanosheets could stabilise BP and increase the BP range. When doped with 0.5 wt% RGO-Az, the mixtures show the wider range with 5.9°C than the range with 3.6°C of BPLCs without RGO-Az. Meanwhile, the phase sequence and the range of the aforementioned phases are reproducible upon heating and cooling, which shows that the BPs doped with RGO-Az nanosheets are thermodynamically stable. 相似文献
Tuning the uniformity and size of binary metal oxide nanodots on graphene oxide (BMO NDs@GO) is significant but full of challenges in wet-chemistry, owing to the difficulties of controlling the complicated cation/anion co-adsorption, heterogeneous nucleation, and overgrowth processes. Herein, the aim is to tune these processes by understanding the functions of various alcohol solvents for NDs growth on GO. It is found that the polyol solvation effect is beneficial for obtaining highly uniform BMO NDs@GO. Polyol shell capped metal ions exhibit stronger hydrogen-bond interactions with the GO surface, leading to a uniform cation/anion co-adsorption and followed heterogeneous nucleation. The polyol-solvated ions with large diffusion energy barrier drastically limit the ion diffusion kinetics in liquids and at the solid/liquid interface, resulting in a slow and controllable growth. Moreover, the synthesis in polyol systems is highly controllable and universal, thus eleven BMO and polynary metal oxide NDs@GO are obtained by this method. The synthetic strategy provides improved prospects for the manufacture of inorganic NDs and their expanding electrochemical applications. 相似文献
This study presents an eco-conscious approach to enhance the efficiency of the Suzuki–Miyaura cross-coupling reaction. We first synthesized graphene oxide nanosheets using the Hummers method and then coated them to incorporate metallic copper on their surface. Following this, we conducted various analyses, including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis, cyclic voltammetry (CV), and energy-dispersive X-ray spectroscopy (EDS) identification, to characterize these modified nanosheets. Subsequently, we utilized Cu-modified graphene oxide nanosheets as cathode catalysts in an electro-oxidation synthesis setup. To verify the effectiveness of this novel approach, we utilized bromobenzene and phenylboronic acid as model substrates to synthesize biphenyl compounds. The reaction yielded impressive product yields ranging from 87% to 93%. Operating under environmentally friendly conditions, this electro-oxidation synthesis not only enhances selectivity but also significantly reduces the environmental impact of the reaction. Our findings highlight the potential of this green chemistry strategy, offering a promising avenue for sustainable and efficient organic synthesis, as evidenced by the successful coupling of bromobenzene and phenylboronic acid with consistently high yields. 相似文献
Graphene and graphene oxide (GO) have garnered significant attention due to their exceptional properties. GO, enriched with various functional groups such as epoxy, hydroxyl, and carboxylic groups, has exhibited remarkable potential in biomedical applications. The combination of GO with metals has proven to be a promising platform for cellular imaging, with this study focusing on the preparation of diverse hybrids of GO with metal oxides (GO/MO) and their potential as anticancer agents. In this research, GO is functionalized with MOs like TiO2, Fe3O4, and Cu2O using specific chemical methods and investigated for the anticancer activity for the application as cancer therapeutic agent. The resulting GO/MO hybrids exhibits favorable thermal and mechanical properties. Moreover, their cytotoxicity against human lung cancer cells is assessed in vitro, revealing the promising anticancer activity of GO/MO hybrids. Notably, the GO/Cu2O hybrid demonstrates particularly high cytotoxicity in human lung cancer cells. 相似文献
Summary: Polyaniline‐vanadium oxide nanocomposite nanosheets with thickness between 10 and 20 nm, and lateral dimensions in the range of hundreds of nanometers to several microns have been synthesized by in situ intercalation polymerization of aniline with layered V2O5 under hydrothermal conditions. The product was characterized by field‐emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT‐IR) spectroscopy, and X‐ray diffractometer (XRD). The effects of the concentration of aniline and reaction temperature on the morphologies of polyaniline‐vanadium oxide nanocomposites have also been investigated.
SEM image of tremella‐like polyaniline‐vanadium oxide nanocomposite nanosheets. 相似文献
The sodium‐ion storage properties of FeS–reduced graphene oxide (rGO) and Fe3O4‐rGO composite powders with crumpled structures have been studied. The Fe3O4‐rGO composite powder, prepared by one‐pot spray pyrolysis, could be transformed to an FeS‐rGO composite powder through a simple sulfidation treatment. The mean size of the Fe3O4 nanocrystals in the Fe3O4‐rGO composite powder was 4.4 nm. After sulfidation, FeS nanocrystals of size several hundred nanometers were confined within the crumpled structure of the rGO matrix. The initial discharge capacities of the FeS‐rGO and Fe3O4‐rGO composite powders were 740 and 442 mA h g?1, and their initial charge capacities were 530 and 165 mA h g?1, respectively. The discharge capacities of the FeS‐rGO and Fe3O4‐rGO composite powders at the 50th cycle were 547 and 150 mA h g?1, respectively. The FeS‐rGO composite powder showed superior sodium‐ion storage performance compared to the Fe3O4‐rGO composite powder. 相似文献
A highly sensitive and selective chemical sensor was prepared based on metallic copper‐copper oxides and zinc oxide decorated graphene oxide modified glassy carbon electrode (Cu?Zn/GO/GCE) through an easily electrochemical method for the quantification of bisphenol A (BPA). The composite electrode was characterized via scanning electron microscopy (SEM), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of BPA in Britton‐Robinson (BR) buffer solution (pH 7.1) was examined using cyclic voltammetry (CV). Under optimized conditions, the square wave voltammetry (SWV) response of Cu?Zn/GO/GCE towards BPA indicates two linear relationships within concentrations (3.0 nmol L?1?0.1 μmol L?1 and 0.35 μmol L?1?20.0 μmol L?) and has a low detection limit (0.88 nmol L?1). The proposed electrochemical sensor based on Cu?Zn/GO/GCE is both time and cost effective, has good reproducibility, high selectivity as well as stability for BPA determination. The developed composite electrode was used to detect BPA in various samples including baby feeding bottle, pacifier, water bottle and food storage container and satisfactory results were obtained with high recoveries. 相似文献
Nowadays graphene is universally known as a promising material. Hence, the development of eco-friendly synthesis methods for this material is of great importance. This study reports on the bio-synthesis of graphene by a green chemistry process using Artemisia herba-alba Asso (AHAA) natural extract. Moreover, this work reports on the physical properties, including surface/interface and optical and electrical properties of the obtained graphene sheets. UV–VIS, Raman, XPS spectroscopies and TEM microscopy investigations confirmed the reduction, and the conversion of graphene oxide to few-layered reduced graphene oxide as well as the efficiency of this plant extract compared with several natural extracts and chemical agents. Furthermore, it was found that the optical and electrical properties of graphene can be modulated and controlled via this eco-friendly cost-effective process. Hence, AHAA can be an effective chelating agent to produce graphene sheets. 相似文献
An efficient chemical way to finely control the layer-by-layer stacking of inorganic nanosheets (NS) is developed by tuning the type and composition of intercalant ion, and the reaction temperature for restacking process. The finely controlled stacking of NS relies on a kinetic control of the self-assembly of NS in the presence of coordinating organic cations. A critical role of organic cations in this assembly highlights the importance of the appropriate activation energy. Of prime importance is that a fine-control of the interstratification of 2D NS is highly effective not only in tailoring its pore structure but also in enhancing its electrode activity. The present study clearly demonstrates that the kinetically controlled restacking of NS provides a facile and powerful method to tailor their stacking number and functionality. 相似文献
Iron(III) oxide (Fe2O3) has attracted great attention, owing to its abundant natural resources, environmental friendliness, and low cost. Nevertheless, this material possesses an inferior rate capability and a cycle stability that is similar to most transition metal oxides. Graphene, with a one-atom-thick 2D structure, possesses superior mechanical properties, electrical conductivity, and stability, and excellent electrical and electrochemical behaviors. The hierarchical structure of graphene/Fe2O3 composites provides a porous conductive network, close contact between the graphene and Fe2O3, a stress buffer space for charge transport, and superior structural stability. This composite consists of high conductivity graphene with interconnected Fe2O3, thus exposing abundant active sites for redox reactions and providing sufficient contacts with the electrolyte. Consequently, materials composed of Fe2O3 and graphene have been widely explored, owing to their outstanding synergistic effects. Graphene can effectively limit the volume expansion and agglomeration of Fe2O3, whereas Fe2O3 can prevent the re-stacking of graphene at the same time. This article mainly discusses the preparation of Fe2O3/graphene materials and their applications, including supercapacitors, rechargeable batteries, catalysis, and so forth. In addition, the perspectives and challenges of Fe2O3/graphene materials for different applications are also discussed. 相似文献
Abstract: Reduced graphene oxide(RGO) was prepared by reducing graphene oxide(GO) with ethylenediamine(EDA). The RGO was characterized by Fourier transform infrared spectroscopy(FT-IR), Raman spectroscopy(Raman), thermogravimetric analysis(TGA), and scanning electron microscopy(SEM). The adsorption behaviors of the RGO toward Pb(Ⅱ), Cd(Ⅱ), Cu(Ⅱ) and Mn(Ⅱ) were studied. The adsorption capacities of RGO are found to be 396.6, 115.3, 54.2 and 38.6 mg/g for Pb(Ⅱ), Cd(Ⅱ), Cu(Ⅱ) and Mn(Ⅱ), respectively. The adsorbed Pb(Ⅱ) on the RGO can be desorbed in 0.05 mol/L HCl solution. After three cycles of adsorption and desorption, the adsorption capacity of RGO toward Pb(Ⅱ) can remain above 85% of the first adsorption amount. 相似文献
In this work we explore the electrocatalytic activity of nanocomposites of reduced sulphur doped graphene oxide nanosheets (rSDGONS) and cobalt phthalocyanine (CoPc) or cobalt tetra amino phthalocyanine (CoTAPc) towards hydrogen peroxide. Transmission electron microscopy, scanning electron microscopy, X‐ray photon spectroscopy, X‐ray diffraction, chronoamperometry, linear scan voltammetry and cyclic voltammetry were used to characterize the nanocomposites. Nanosized CoPc showed superior (in terms of currents) electrocatalytic oxidation and reduction of hydrogen peroxide compared to CoTAPc nanoparticles (CoTAPc NP ). The lowest detection limit was obtained for hydrogen peroxide oxidation on electrodes modified with CoPc NP ‐rSDGONS at 1.49 µM. The same electrode gave a high adsorption equilibrium constant of 1.27×103 mol?1 and a Gibbs free energy of ?17.71 kJ/mol, indicative of a spontaneous reaction on the electrode surface. 相似文献
Metal–organic framework (MOF) and covalent organic framework (COF) nanosheets are a new type of two-dimensional (2D) materials with unique design principles and various synthesis methods. They are considered ideal electrochemical devices due to the ultrathin thickness, easily tunable molecular structure, large porosity and other unique properties. There are two common methods to synthesize 2D MOF/COF nanosheets: bottom-up and top-down. The top-down strategy mainly includes ultrasonic assisted exfoliation, electrochemical exfoliation and mechanical exfoliation. Another strategy mainly includes interface synthesis, modulation synthesis, surfactant-assisted synthesis. In this Review, the development of ultrathin 2D nanosheets in the field of electrochemistry (supercapacitors, batteries, oxygen reduction, and hydrogen evolution) is introduced, and their unique dimensional advantages are highlighted. 相似文献
Since George R. Pettit’s group isolated cycloheptapeptide phakellistatin 1 from sponge1, over ten similar cyclic peptides have been obtained2-5. Phakellistatin 134 (Figure 1) is a cycloheptapeptide isolated from the brown snubby sponge from the South Chi… 相似文献
Summary A number of supported metal oxide catalysts were prepared and tested for nitrogen oxide removal from diesel engine exhaust. More than 50% of nitrogen oxides were removed using many prepared catalysts in the temperature range of 150oC-350oC. 相似文献
