Simultaneous Laser‐Induced Reduction and Nitrogen Doping of Graphene Oxide in Titanium Oxide/Graphene Oxide Composites

Titanium oxide/graphene oxide nanocomposite thin films were grown by ultraviolet (UV) matrix‐assisted pulsed laser evaporation (MAPLE) technique in controlled oxygen or nitrogen atmospheres. The effect of graphene oxide addition and laser‐induced reduction as well as nitrogen doping on the wetting behavior and photoactive properties of titanium oxide thin films was investigated. Hydrophobic to hydrophilic conversion of titanium oxide films takes place progressively as the relative amount of graphene oxide in the MAPLE composite target increases. Nitrogen doping leads to further decrease of the static contact angle of the composite films. The photoactive properties of the synthesized materials were investigated through the evolution of contact angle under UV light irradiation. Wetting properties of both TiO₂ and TiO₂/GO nanocomposite thin films improved upon exposure to UV light.     

Synergetic Effects of Graphene Oxide and Clay on the Microstructure and Properties of HIPS/Graphene Oxide/Clay Nanocomposites

In this paper, double-network structure nanocomposite with improved mechanical and thermal properties were prepared using high-impact polystyrene as a matrix phase, clay and graphene oxide as effective reinforcing fillers through a facile solution intercalation method. The structure and morphology of nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction analysis, and the synergetic effects of clay and graphene oxide on the final properties were investigated using tensile, dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA) analysis. Mechanical analysis showed that the combination of graphene oxide and clay exerted a favorable synergistic effect on the tensile modulus and the yield strength of the ternary composite that are greatly improved as compared with neat high-impact polystyrene, high-impact polystyrene/graphene oxide, and high-impact polystyrene/clay binary composites due to the double-network structure formation between the nanofillers as confirmed by the direct morphological observations using transmission electron microscopy and scanning electron microscopy analysis. The viscoelastic behavior showed that storage modulus of ternary composite significantly improvement over than that of the pure matrix, high-impact polystyrene/graphene oxide and high-impact polystyrene/clay while network structure made. TGA and DMTA measurements also demonstrated that thermal stability of high-impact polystyrene matrix modified by graphene oxide and clay slightly enhanced during the creation of dual network structure of graphene oxide and clay. Our data suggest a potential application for the combination of graphene oxide and clay in graphene-based composite materials.     

氧化石墨烯对浮萍生长的抑制作用

以浮萍作为受试生物,分别以质量浓度为1、5、10 mg/L的氧化石墨烯碎片悬浮液,对浮萍进行96 h暴露处理,以分析氧化石墨烯对浮萍生长的影响。结果显示,10 mg/L的氧化石墨烯对浮萍叶片数和湿重的抑制率分别约为35.3%和26.1%,显著(P0.05)抑制了浮萍的生长;低浓度的氧化石墨烯对浮萍抗氧化酶无明显影响,当其浓度达10 mg/L时,浮萍内超氧化物歧化酶(SOD)过氧化氢酶(CAT)水平明显(P0.05)升高;过氧化物酶(POD)的活性则随着氧化石墨烯浓度的增加出现"低促高抑"的趋势。研究结果说明,氧化石墨烯在具有环境意义的低浓度下对浮萍无明显抑制作用,但在较高浓度(10 mg/L)下对浮萍具有显著的胁迫效应。     

氨基改性氧化石墨烯及其与环氧树脂的复合

对氧化石墨烯的氨基改性进行了研究,并探索了其在环氧树脂复合材料中的应用。以鳞片石墨为原料,采用Hummers法制备了氧化石墨,进而超声剥离制备了氧化石墨烯。采用三乙烯四胺和乙二胺,用缩合剂法对氧化石墨烯进行改性,并制备相应的环氧树脂复合材料。通过X射线衍射、热重分析、红外光谱、拉曼光谱、扫描电子显微镜等测试方法对所制备的材料进行了表征。结果表明,通过改性可将三乙烯四胺和乙二胺引入氧化石墨烯的表面,且氧化石墨烯被部分还原;氨基改性氧化石墨烯作为分散相加入环氧树脂基体中制备的复合材料的弹性模量和拉伸强度较纯环氧树脂明显提高,拉伸强度最大提高约60 %,弹性模量最大提高约100 %。     

Nanoarchitectonics of Cerium Oxide/Zinc Oxide/Graphene Oxide Composites for Evaluation of Cytotoxicity and Apoptotic Behavior in HeLa and VERO Cell Lines

Journal of Inorganic and Organometallic Polymers and Materials - Using the ultrasonic approach, we produced a morphology involving a cerium oxide/ zinc oxide/graphene oxide nanocomposite-based...     

氨水改性氧化石墨烯高效催化 Knoevenagel缩合反应

通过浸渍法制备了氨水改性氧化石墨烯,考察了其在苯甲醛和丙二腈的Knoevenagel缩合反应中的催化性能。通过X射线粉末衍射(XRD)、拉曼光谱(Raman)、傅里叶变换红外光谱(FTIR)、NH3程序升温脱附(NH3-TPD)、元素分析等对催化剂进行了表征,考察了工艺条件对其催化剂性能的影响。结果表明:氨水改性氧化石墨烯可以有效地将NH4+固载于氧化石墨烯表面;氧化石墨烯经氨水改性后在苯甲醛和丙二腈的Knoevenagel缩合反应中表现出良好的催化性能,随着改性实验中氨水质量分数的增加,催化剂的活性不断增加。以质量分数5%的氨水为改性剂制备的催化剂(AW-GO-5%)在60℃、4 h下催化苯甲醛和丙二腈的Knoevenagel缩合反应,苯甲醛的转化率高达93.6%,产物苄亚基丙二腈的选择性为94.8%,该催化剂重复使用4次后催化活性仍较高。     

水热体系中氧化石墨烯复合金颗粒的合成及表征

在200℃自气压水热条件下制备了氧化石墨烯复合金.使用X射线粉末衍射仪(XRD)、扫描电子显微镜( SEM)、透射电子显微镜(TEM)等一系列仪器进行表征,结果表明氧化石墨烯复合金由大约5μm的金颗粒与氧化石墨烯复合而成,形貌分析表明氧化石墨烯对金颗粒的形成和进一步演化起到了一定的作用.     

Effect of Graphene Oxide on Structure and Properties of Impact-Modified Polyamide 6

Modification of polymer blends with nanofillers is an efficient way to improve material parameters. This work deals with application of neat and stearylamine-modified graphene oxide in the polyamide 6/elastomer system using different mixing protocols. Combination of ethene–propene elastomer and graphene oxide leads to a polyamide material with increased strength, stiffness, and toughness. The reason is synergistic effect of the core–shell structure (nanofiller localized at interface) on mechanical properties. The structure-directing effect of graphene oxide is comparable with that of nanoclay. The mechanism of affecting dynamic phase behavior is different as a consequence of graphene oxide nature and interactions with polymer components.     

Boosting CO Hydrogenation Performance of Facile Organics Modified Iron Oxide/Reduced Graphene Oxide Catalysts

Catalysis Letters - Organics including terephthalic acid and glucose are added to selectively adsorb on iron oxide or graphene oxide, which can further modify the structure properties and...     

Enhancement in Performance of Sulfonated PES Cation-Exchange Membrane by Introducing Pristine and Sulfonated Graphene Oxide Nanosheets Synthesized through Hummers and Staudenmaier Methods

Sulfonated polyether sulfone-based cation-exchange membranes are prepared by incorporating different amounts of graphene oxide and sulfonated graphene oxide nanosheets. The graphene oxide nanosheets are synthesized according to Staudenmaier and Hummer methods and functionalized using 3-mercaptopropyl trimethoxysilane. Transport properties of nanocomposite membranes including ion-exchange capacity, transport number, and conductivity as well as their thermal stabilities are enhanced by incorporating sulfonated graphene oxide rather than graphene oxide. Also, the enhancement is more significant for the nanocomposites having functionalized graphene oxide synthesized by Staudenmaier method than those by Hummers method due to higher density of active sites in the Staudenmier graphene oxides for functionalization.     

氧化石墨烯对新拌水泥浆体流变性的影响

随着纳米材料和技术不断发展,关于氧化石墨烯对水泥基材料改性作用的相关研究越来越受到重视。在此背景下,通过Anton Paar Rheolab QC型旋转黏度计研究了氧化石墨烯对新拌水泥浆体流变性的影响,并测试了浆体静态屈服应力、动态屈服应力和黏度系数以及触变环面积。结果表明:相同氧化石墨烯掺量下,随浆体静置时间延长,低剪切速率下浆体的静态屈服应力逐渐增大;随氧化石墨烯掺量增大,浆体结构建立参数、动态屈服应力和黏度系数先增大后减小,而触变滞后环面积则呈现相反的变化趋势。     

磁性氧化石墨烯的制备及其对Pb~(2+)的吸附研究

采用一步共沉淀法,以FeCl_2·4H_2O、FeCl_3·6H_2O和氧化石墨烯为原料,在碱性条件下制备得到氧化石墨烯/四氧化三铁的磁性复合材料,通过红外、热质量和XRD等测试手段对复合材料的结构进行了表征,采用紫外分光光度计法进行了复合材料对Pb~(2+)溶液的吸附分离实验。结果表明,制备所得到的磁性氧化石墨烯复合材料对Pb~(2+)具有良好的吸附性能和磁性分离效果。     

Eco-Friendly Electromagnetic Interference Shielding Materials from Flexible Reduced Graphene Oxide Filled Polycaprolactone/Polyaniline Nanocomposites

Hybrid nanocomposites have the unique ability of enhancing material properties due to the existing synergistic effect of the fillers. In this study, the authors report such an eco-friendly hybrid nanocomposite comprising of polyaniline and reduced graphene oxide in polycaprolactone. The conducting polyaniline improved the processability of polycaprolactone, and the final composites were prepared by incorporating graphene oxide reduced at 200 and 600°C temperatures to the polycaprolactone–polyaniline blend. Polyaniline, polyaniline/reduced graphene oxide200, and polyaniline/reduced graphene oxide600 imparted good electrical conductivity to polycaprolactone, and the fabricated flexible polycaprolactone–polyaniline/reduced graphene oxide nanocomposites exhibited good mechanical property, increased thermal stability, and excellent electromagnetic interference shielding up to 42 dB at 13 GHz.     

Defluoridation of Water by Graphene Oxide Supported Needle-Like Complex Adsorbents

The dicarboxylic acids like oxalic acid, malonic acid and succinic acid mediated graphene oxide–zirconium needle like complexes were synthesized and used to remove fluoride from simulated fluoride contaminated water. The adsorption of fluoride by dicarboxylic acids mediated graphene oxide–zirconium complexes were by both electrostatic interaction at acidic pH and ion-exchange mechanism at neutral pH. The maximum defluoridation capacity observed was 9.70 mg/g at the minimum contact time of 18 min at room temperature. Various batch equilibrium parameters like pH studies, contact time, common ion interference and temperature studies were optimized. The synthesized graphene oxide and graphene oxide supported complexes were characterized using UV–vis, FTIR, XRD and SEM with EDAX analysis to establish the mechanism of fluoride adsorption. The removal of fluoride was described by the pseudo-second-order reaction kinetics, Freundlich isotherm model and thermodynamic studies which indicates the nature of adsorption was endothermic and spontaneous. Regeneration studies depict that the dicarboxylic acid mediated graphene oxide–zirconium complex can be used as an effective adsorbent for the removal of fluoride ions from wastewater. Also, the field applicability of the material has been verified with field samples collected from nearby fluoride endemic villages.     

Surface Modification of Graphene Oxide and Investigation of Its Effects on Surface Properties of Aramid Membranes

To manufacture aramid thin-film-composite membrane for desalination application (reverse osmosis) via in situ interfacial polymerization, the different weight percents of modified graphene oxide were applied into the aramid layer during interfacial polymerization. The dispersion of the modified graphene oxide was investigated by X-ray Diffraction (XRD) and Transition Electron Microscopy (TEM) methods. Also, the effect of the modified graphene oxide on the surface chemical composition and surface morphology of aramid membrane was investigated by Attenuated Total Reflectance-Infrared Spectroscopy (ATR-IR), scanning electron microscopy, and atomic force microscopy, respectively. The results showed that in the presence of the modified graphene oxide, the interfacial polymerization reaction is transferred between the nanoparticles so the depth of surface porosity is increased strongly. In addition, the hydrophilic value of aramid layer in the presence of the modified graphene oxide firstly increased up to 0.15 wt% but with an increase in the modified graphene oxide percent at 0.2 wt%, the surface hydrophilicity decreased gradually. As a result, the optimum hydrophilic and morphological properties were observed in samples containing 0.15 wt% of modified graphene oxide.     

Characterization and Properties of Poly(methyl methacrylate)/Graphene,Poly(methyl methacrylate)/Graphene Oxide and Poly(methyl methacrylate)/p-Phenylenediamine-Graphene Oxide Nanocomposites

In this study, poly(methyl methacrylate)/p-phenylenediamine-graphene oxide, poly(methyl methacrylate)/graphene, and poly(methyl methacrylate)/graphene oxide nanocomposite series were prepared using simple solution blending technique. In poly(methyl methacrylate)/p-phenylenediamine-graphene oxide series, graphene oxide modified with p-phenylenediamine was used to improve its dispersion and interfacial strength with matrix. Morphology study of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide nanocomposite revealed better dispersion of p-phenylenediamine-graphene oxide flakes and gyroid patterning of poly(methyl methacrylate) over the filler surface. Due to nonconducting nature of graphene oxide, there was no significant variation in the thermal or electrical conductivity of these nanocomposites. Thermal conductivity of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide 1.5 was 1.16 W/mK, while the electrical conductivity was found to be 2.3 × 10^?3 S/cm.     

Influence of the Reduction of Graphene Oxide with Hydroiodic Acid on the Structure and Photoactivity of CdS–rGO Hybrids

The temperature used in the chemical reduction of graphene oxide (GO) with hydroiodic acid has a significant influence on the removal of surface oxygenated functional groups, on the residual iodine species and on the rupture, stacking and graphitization of the graphene sheets in the reduced graphene oxides. The modification in the characteristics of the reduced graphene oxides induces changes in the surface area, the exposition of reduced graphene oxide entities and in the concentration of small CdS nanocrystals with strong confinement effect on the CdS-reduced graphene oxide hybrids. The hybridization of the reduced graphene oxide with CdS modifies in different way their photocatalytic behavior for hydrogen production from aqueous solutions of Na₂S and Na₂SO₃ under simulated sunlight irradiation. Only the hybrid formed between the CdS and the reduced graphene oxide treated at higher temperature showed improved hydrogen production rate respect to the bare CdS reference associated with the better conductivity of the reduced graphene oxide and with the increase in the concentration of small CdS nanocrystals sith strong confinement effect observed in the hybrid.     

Enhancement of Electrical and Dielectric Properties of Graphene Oxide‐nanoparticle Based Devices

Silicon - The aim of this work is to invent a novel technology for manufacture not only graphene oxide, but also conductive graphene oxide. This is the novelty in this technology, which is not...     

Progression from Graphene and Graphene Oxide to High Performance Polymer-Based Nanocomposite: A Review

In this article, various types of carbon nanofiller and modification of graphene oxide and graphene for the preparation of polymer-based nanocomposites are reviewed. Recently, polymer/graphene and graphene oxide-based materials have attracted tremendous interest due to high performance even at low filler content. The property enhancement is due to the high aspect ratio, high surface area and excellent electrical, thermal and mechanical properties of nanofiller. Different techniques have been employed to fabricate polymer/graphene and graphene oxide nanocomposite with uniform dispersion due to fine matrix/nanofiller interaction. Here we discuss the structure, properties and preparation of these nanocomposites.     

功能化还原氧化石墨烯/天然橡胶导热复合材料的性能研究

采用2-巯基苯并咪唑(防老剂MB,以下简称MB)对氧化石墨烯(GO)进行还原及功能化,同时与采用抗坏血酸(VC)对GO进行还原对比,分别制得MB还原氧化石墨烯(rGO-MB)和VC还原氧化石墨烯(rGO-VC),并采用胶乳共混法制备rGO-MB/NR和rGO-VC/NR复合材料,对其性能进行研究。结果表明:MB成功还原了GO,MB接枝到了GO上;与rGO-VC/NR复合材料相比,rGO-MB/NR复合材料具有较低的Payne效应和较高的结合胶含量,拉伸强度和导热性能均明显提高。