Abstract:The diversity of zinc oxide (ZnO) particles and derived composites applications is highly dependent on their structure, size, morphology, defect amounts, and/or presence of dopant molecules. In this work, ZnO nanostructures are grown in situ on graphene oxide (GO) sheets by an easily implementable solvothermal method with simultaneous reduction of GO. The effect of two zinc precursors (zinc acetate (ZA) and zinc acetate dihydrate (ZAD)), NaOH concentration (0.5, 1 or 2 M), and concentration (1 and 12.5 mg/mL) … Show more
“…Furthermore, ZnO nanostructures were grown in situ with simultaneous reduction of GO sheets by a solvothermal method using ethanol as solvent. The obtained ZnO-rGO nanostructures can be used as functional fillers due to the antimicrobial activity of ZnO [42]. Narayanan et al [25] also reported the hydrothermal synthesis of rGO using starch as reducing agent.…”
Carbon nanostructures are widely used as fillers to tailor the mechanical, thermal, barrier, and electrical properties of polymeric matrices employed for a wide range of applications. Reduced graphene oxide (rGO), a carbon nanostructure from the graphene derivatives family, has been incorporated in composite materials due to its remarkable electrical conductivity, mechanical strength capacity, and low cost. Graphene oxide (GO) is typically synthesized by the improved Hummers’ method and then chemically reduced to obtain rGO. However, the chemical reduction commonly uses toxic reducing agents, such as hydrazine, being environmentally unfriendly and limiting the final application of composites. Therefore, green chemical reducing agents and synthesis methods of carbon nanostructures should be employed. This paper reviews the state of the art regarding the green chemical reduction of graphene oxide reported in the last 3 years. Moreover, alternative graphitic nanostructures, such as carbons derived from biomass and carbon nanostructures supported on clays, are pointed as eco-friendly and sustainable carbonaceous additives to engineering polymer properties in composites. Finally, the application of these carbon nanostructures in polymer composites is briefly overviewed.
“…Furthermore, ZnO nanostructures were grown in situ with simultaneous reduction of GO sheets by a solvothermal method using ethanol as solvent. The obtained ZnO-rGO nanostructures can be used as functional fillers due to the antimicrobial activity of ZnO [42]. Narayanan et al [25] also reported the hydrothermal synthesis of rGO using starch as reducing agent.…”
Carbon nanostructures are widely used as fillers to tailor the mechanical, thermal, barrier, and electrical properties of polymeric matrices employed for a wide range of applications. Reduced graphene oxide (rGO), a carbon nanostructure from the graphene derivatives family, has been incorporated in composite materials due to its remarkable electrical conductivity, mechanical strength capacity, and low cost. Graphene oxide (GO) is typically synthesized by the improved Hummers’ method and then chemically reduced to obtain rGO. However, the chemical reduction commonly uses toxic reducing agents, such as hydrazine, being environmentally unfriendly and limiting the final application of composites. Therefore, green chemical reducing agents and synthesis methods of carbon nanostructures should be employed. This paper reviews the state of the art regarding the green chemical reduction of graphene oxide reported in the last 3 years. Moreover, alternative graphitic nanostructures, such as carbons derived from biomass and carbon nanostructures supported on clays, are pointed as eco-friendly and sustainable carbonaceous additives to engineering polymer properties in composites. Finally, the application of these carbon nanostructures in polymer composites is briefly overviewed.
“…41 Different synthetic methodologies have been adopted to synthesize nanocomposites, but hydrothermal method can be distinguished due to its high efficiency, controllable morphologies, uniformity and growth, low cost, easy processing, and eco-friendly nature as it does not use any hazardous solvent. 42,43 Thus, in this research work, hydrothermal synthesis method has been used to prepare rhinestone sheet like nanocomposites using CDs, ZnO, and rGO. It has been proposed that CDs and ZnO nanoparticles have been attached onto the rGO nanosheets during the reaction.…”
Summary
The increasing thrust lies in developing a better electrode material for supercapacitor applications. Carbon and metal oxide‐based nanocomposites are the latest trend in this research area. In the present work, we are proposing the synthesis of simple, eco‐friendly and cost‐effective reduced graphene oxide (rGO), naturally derived carbon dots (CDs), and zinc oxide (ZnO)‐based rZD ternary nanocomposites. These nanocomposites have been synthesized using eco‐friendly and accessible hydrothermal method at three different temperatures (i.e., 300, 400, and 500°C) and accordingly named as rZD300, rZD400, and rZD500. Further, the morphological (scanning electron microscopy and transmission electron microscopy) characterization studies predicted that ZnO and CDs were attached on to the rGO nanosheets to form the rhinestone sheet like structures. In addition, the crystalline and structural properties have been examined using X‐ray diffraction, Raman, X‐ray Photoelectron Spectroscopy, and X‐ray Absorption Spectroscopy. The electrochemical studies (cyclic voltammetry, galvanostatic charge‐discharge, and electrochemical impedance spectroscopic) predicted that highest capacitance achieved was 796 F/g using 2 M H2SO4 electrolytic solution for rZD500 nanocomposite. Finally, 1.5 V prototype flexible Supercapacitors (FSC) have been also fabricated using carbon cloth substrate for rZD500nanocomposite.
“…However, the DPs of GO are not clearly identified for the prepared samples. This can be attributed to the addition of a small amount of graphene during the synthesis process as well as the low-diffraction intensity of GO sheets [17]. The crystallite size "L" of the prepared samples is calculated using the Scherrer equation as mentioned in the previous work [18].…”
Graphene oxide (GO) nanostructures are systems with many fascinating novel properties that can be used to study new science and have significant promise for applications. In this study, graphene oxide was prepared using the modified Hummer’s method. In addition, potassium ferrite is a good candidate for biomedical application, as iron and potassium are biocompatible and non-toxic materials. Mg0.85K0.3Fe2O4/GO nanocomposites were prepared by the citrate auto-combustion method. The effect of adding GO to Mg0.85K0.3Fe2O4 on structure, morphology, electrical, and magnetic properties was discussed. Samples under investigation were characterized using XRD, infrared spectroscopy (IR), high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM). The crystallite size of prepared samples was decreased from 28.098 to18.148 nm by increasing GO content. Scanning electron microscope (SEM) confirms the successful adhesion of Mg0.85K0.3Fe2O4 nanoparticles on graphene oxide sheets, which are dispersed in a metal oxide matrix. EDAX analysis confirms the existence of C, O, K, Mg, and Fe elements present in the samples. Magnetic properties were studied by VSM and Faraday's method. GO has a significant effect on the magnetic properties of nanocomposites. For instance, the saturation magnetization and Curie temperature have diverse values, which will be appropriate for numerous applications.
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