高介电常数石墨烯/聚酰亚胺复合材料的制备与性能

在原位聚合制备氧化石墨烯/聚酰亚胺复合材料的过程中,加入季铵盐表面活性剂,抑制氧化石墨烯在高温亚胺化时的聚集,同时将氧化石墨烯原位还原,获得高介电常数的石墨烯/聚酰亚胺复合材料.结果表明,采用四丁基溴化铵和四丁基碘化铵作为还原剂,利用原位化学还原方法所制备的石墨烯/聚酰亚胺复合材料的介电常数超过聚酰亚胺薄膜40倍以上,复合材料的热稳定性和机械性能也优于聚酰亚胺薄膜.热重分析结果表明,在复合材料高温亚胺化过程中,季铵盐发生热分解,未残留在复合材料中.     

Synthesis and Electrochemical Performance of Co3O4/Graphene

Co3O4/reduced graphene oxide composites were synthesized via a simple electrochemical method from graphene oxide and Co（NO3）2·6H2O as raw materials.Co3O4 nanoparticles with sizes of around 30-50 nm were distributed on the surface of graphene nanosheets confirmed by scanning electron microscopy and transmission electron microscopy.Electrochemical properties of Co3O4/graphene composite were tested by cyclic voltammetry,galvanostatic charge-discharge,and electrochemical impedance spectroscopy.The Co3O4/reduced graphene oxide composite was used as the pseudocapacitor electrode in the 2 mol/L NaOH aqueous electrolyte solution.The Co3O4/reduced graphene oxide composite electrode exhibited a specific capacitance of 357 F/g at a current density of 0.5 A/g in a three-electrode system.72％ of capacitance was retained when the current density increased to 3 A/g.The Co3O4/reduced graphene oxide composite prepared electrodes show a high rate capability and excellent long-term stability.After 1000 cycles of charge and discharge,the capacitance is still maintained 87％ at a current density of 1 A/g,indicating that the composite is a oromising alternative electrode material used for supercapacitors.     

Ag/Fe_3O_4/rGO纳米复合材料的制备及抗菌性能

以四水合氯化亚铁和硝酸银为原料,硼氢化钠为还原剂,氧化石墨烯(GO)为载体,通过原位还原法制备了具有磁分离功能的银/四氧化三铁/还原氧化石墨烯(Ag/Fe_3O_4/rGO)纳米复合抗菌材料.采用X射线粉末衍射仪(XRD)、X射线光电子能谱仪(XPS)、透射电子显微镜(TEM)等对复合材料进行了表征.结果显示,Fe_3O_4和Ag纳米颗粒均匀分布在rGO片层上.复合材料的饱和磁化率(Ms)为40.5 A·m~2·kg·(-1),表明其具有较强的磁性,将其与菌液混合后,在磁场作用下10 min即可吸附沉降完成磁分离.以大肠杆菌(E.coli)和金黄色葡萄球菌(S.aureus)为实验菌株,通过琼脂扩散法评价了复合材料的抗菌性能.结果表明,该复合材料具有良好的抗菌效果,对E.coli和S.aureus的抑菌圈直径分别为18 mm和13 mm,最低抑菌浓度值(MIC)分别为50 mg/L和80 mg/L,最低杀菌浓度值(MBC)分别为30 mg/L和50 mg/L.     

Bio‐inspired method to fabricate poly‐dopamine/reduced graphene oxide composite membranes for dyes and heavy metal ion removal

Due to the narrow layer spacing, graphene oxide (GO) composite membrane usually exhibits a relatively low water flux in the process of wastewater treatment. In this study, GO was reduced to reduced graphene oxide through a bio‐inspired method, which was functionalized modified by poly‐dopamine (PDA). Then a series of PDA/reduced graphene oxide sheet films were prepared by vacuum filtration on the surface of cellulose acetate membrane (under the pressure of −0.1 MPa). The result indicated that the novel membranes had an excellent stability owing to the cross‐link of PDA. In addition, the hydrophilicity of membrane was increased significantly after PDA modification, which presented a superior water flux than pure GO composite membrane. More importantly, as‐prepared membranes were successfully applied for the removal of dyes (including Congo red, methylene blue, and rhodamine B) and heavy mental ion (Cu(II)) from simulated wastewater. This work might provide a new method for preparation and application of GO composite membranes.     

Synthesis and electrochemical performance of sandwich-like polyaniline/graphene composite nanosheets

Sandwich-like polyaniline/graphene composite nanosheets have been synthesized by chemical oxidation polymerization of aniline monomer on the surfaces of reduced graphene oxide nanosheets in the absence of any surfactants. The influences of the mass ratios of aniline and reduced graphene oxide on the sizes and morphologies of polyaniline/graphene nanocomposites have been investigated. As the mass ratio of aniline and reduced graphene oxide is smaller than 12:1, polymerization reaction of aniline occurs on the surfaces of reduced graphene oxide by heterogeneous nucleation to form sandwich-like polyaniline/graphene composite nanosheets. However, besides sandwich-like polyaniline/graphene composite nanosheets, polyaniline nanofibers are formed by homogeneous nucleation. In comparison with reduced graphene oxide and polyaniline nanofibers, the obtained sandwich-like polyaniline/graphene composite nanosheets exhibit good electrochemical performances due to the synergistic effect between graphene and polyaniline.     

石墨烯/铂复合材料的制备及电化学性能研究

采用Hummers法制备氧化石墨,再超声分散于去离子水中形成稳定的氧化石墨分散液。分散液与氯铂酸溶液混合后,氧化石墨烯还原氯铂酸产生大量铂纳米粒子,铂粒子被牢固地锚在氧化石墨烯片上,最后将所得到的氧化石墨烯/铂复合物置于管式炉中在Ar/H2气氛中于800℃下热裂解制备出石墨烯/铂复合材料。形貌与纳米结构分析表明,氧化石墨已被彻底还原成石墨烯,铂纳米粒子均匀分散在褶皱的石墨烯纳米片间。电化学阻抗研究进一步揭示复合材料的电子转移阻抗明显小于石墨烯,呈示铂纳米粒子掺入石墨烯片层大大改善了导电性。石墨烯/铂复合材料应用于对苯二酚的电化学检测,检出限达1.6×10-7mol.L-1,这说明该材料具有优异的电催化性能。     

部分还原氧化石墨烯/二氧化钛复合材料的水热合成及其光催化活性

采用水热法以Hummers氧化法制备的氧化石墨和钛酸四丁酯为原料制备了部分还原的氧化石墨烯/二氧化钛(RGO/TiO₂)复合光催化剂, 并研究了该复合材料在可见光以及紫外光下对亚甲基蓝的光催化降解活性.结果表明, 通过改变反应温度和氧化石墨加入量可以调控TiO₂的晶相组成及其在复合材料中的分散性; 在水热反应过程中氧化石墨烯发生了部分还原; 所制备的RGO/TiO₂复合材料的可见光和紫外光催化活性均高于纯TiO₂; 部分还原的氧化石墨烯在复合材料中担当载体和电子受体, 同时可以使TiO₂的初始吸收边向可见光区域红移, 增强了TiO₂在可见光区域的吸收, 能有效提高对目标污染物的吸附性和光催化降解活性.     

A composite polyaniline/graphene–coated polyamide6 nanofiber mat for electrochemical applications

In this study, polyamide6 (PA6) nanofiber mats were fabricated through the electrospinning process. The nanofibers were coated by polyaniline (PANI) using the in situ polymerization of aniline in the presence of graphene oxide. The composite of the PANI/graphene oxide–coated nanofiber mat was treated with hydrazine monohydrate to reduce graphene oxide to graphene, and this was followed by the reoxidation of PANI. Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), wide angle X‐ray diffraction (WAXD), thermal gravimetric analysis (TGA), tensile strength tests, electrical conductivity measurements, cyclic voltammetry (CV), and charge/discharge measurements were conducted on the composite PA6/graphene nanofiber mats. It was found that the surface of the PA6 nanofibers was coated uniformly with the granular PANI and graphene oxide. Besides, the composite nanofibers showed good tensile and thermal properties. Their electrical conductivity and specific capacitance, when used as a separator in the cell, were 1.02 × 10^?4 S/cm and 423.28 F/g, respectively. Therefore, the composite PANI/reduced graphene oxide–coated PA6 nanofiber mats could be regarded as suitable candidates for application in energy storage devices.     

A novel ZnO/reduced graphene oxide and Prussian blue modified carbon paste electrode for the sensitive determination of Rutin

Science China Chemistry - A carbon paste modified sensor based on a novel composite of zinc oxide nanoparticles deposited on reduced graphene oxide (ZnO-rGrO) and Prussian blue (PB) was drop-cast...     

Synthesis of dendritic platinum nanoparticles/lucigenin/reduced graphene oxide hybrid with chemiluminescence activity

Multifunctional hybrid: A dendritic platinum nanoparticle/lucigenin/reduced graphene oxide (RGO) hybrid with chemiluminescence (CL) activity was prepared for the first time by using lucigenin as a linker through simultaneous reduction of H(2) PtCl(4) and a lucigenin-functionalized graphene oxide composite by sodium borohydride (see scheme). The hybrid may have potential applications as a CL sensor, in catalysis, energy conversion, and opto-electronic systems.     

Performance of graphene Oxide/SiO2 Nanocomposite-based: Antibacterial Activity,dye and heavy metal removal

Nanocomposite materials have been successfully applied to remediation of organic and inorganic contaminants from polluted water. The present study investigates the synthesis, characterizations, and adsorptive performances of graphene oxide/SiO₂ nanocomposite-based adsorbent. Graphene oxide/SiO₂ was used for the adsorption of methylene blue (MB) and Cr (VI) ion from wastewater. Furthermore, the antibacterial activity performance of synthesized nanocomposite was studied. The adsorption consideration has been performed by various adsorption parameters in our laboratory. X-ray crystallography (XRD), Scanning electron microscope (SEM), Energy Dispersive X-ray Analysis (EDX) and, thermal gravimetric analysis (TGA) methods were applied in the characterization, morphological structure, crystallinity, and thermal stability of graphene oxide/SiO₂. Maximum capacities of adsorption of graphene oxide/SiO₂-based adsorbent had been evaluated by the Langmuir isotherm model for MB and Cr (VI) ion as 555.50 and 181.81 mg/g, respectively. Generally, adsorption experiments revealed that the performances of graphene oxide/SiO₂ nanocomposite for all adsorbents have been found in the order MB > Cr (VI). Furthermore, antibacterial activity study against gram-positive and gram-negative bacteria showed and proved that graphene oxide/SiO₂ composite showed a remarkable ability to kill bacteria.     

Alkaline hydrolysis of brilliant green in mixed cationic surfactant systems

Kinetic measurements were performed for the alkaline hydrolysis of brilliant green — a triphenylmethane dye used as a model compound for probing micellar rate effects. This reaction was studied both in the presence of tetradecyltrimethylammonium bromide (TTAB) and tetradecyltriphenylphosphonium bromide (TTPPBr) and also in binary mixtures of these surfactants at different mole fractions of each. All rate surfactant profiles were analyzed using the pseudo-phase model in order to obtain the regression parameters, including binding constants and rate constants in the micellar pseudo-phase. The reaction was catalyzed by both surfactants. The catalytic factor increases from about 10 for pure TTPPBr to about 38 for pure TTAB. Binding of BG to micellar surface is greater in pure TTAB than in pure TTPPBr but significantly reduced in the surfactant mixtures than in pure components. Reduction of the binding constant becomes more significant as the mole fraction of TTAB is increased in the mixture. The kinetic data have been analyzed in terms of models of Piszkiewicz and Raghavan-Srinivasan which are in good agreement.      

氢氧化镍纳米线/三维石墨烯复合材料的制备及其电化学性能

采用水热法制备了氢氧化镍纳米线/三维石墨烯复合材料及作为比较的三维石墨烯、氢氧化镍纳米线、还原氧化石墨烯和氢氧化镍纳米线/还原氧化石墨烯, 通过X射线衍射、扫描电镜、热失重分析和氮气吸脱附表征了材料的形貌、结构和组成, 并采用循环伏安法和恒电流充放电测试了复合材料的电化学性能. 结果表明: 氢氧化镍纳米线/三维石墨烯复合材料中直径为20-30 nm的氢氧化镍纳米线和三维结构的石墨烯紧密结合, 相互交联形成网状结构, 其比表面积达到136 m²·g^-1, 孔径分布20-50 nm, 氢氧化镍纳米线的含量达到88% (w,质量分数). 在6 mol·L^-1的KOH电解液中, 复合材料的比电容在1 A·g^-1电流密度下达到1664 F·g^-1, 在1 A·g^-1电流密度下循环3000 次后的比电容保持率为93%. 将复合材料的比电容和循环性能与氢氧化镍纳米线、氢氧化镍纳米线/还原氧化石墨烯、三维石墨烯和还原氧化石墨烯的性能进行比较, 发现三维石墨烯较还原氧化石墨烯具有更高的比表面积和三维多孔结构, 可以更大地提高活性物质的利用率, 进而提高复合材料的比电容和稳定性.     

Novel Poly(vinyl alcohol)/Chitosan/Modified Graphene Oxide Biocomposite for Wound Dressing Application

Rapid absorption of wound exudate and prevention of wound infection are prerequisites for wound dressing to accelerate wound healing. In this study, a novel kind of promising wound dressing is developed by incorporating polyhexamethylene guanidine (PHMG)‐modified graphene oxide (mGO) into the poly(vinyl alcohol)/chitosan (PVA/CS) matrix, conferring the dressing the required mechanical properties, higher water vapor transmission rate (WVTR), less swelling time, improved antibacterial activity, and more cell proliferation compared to the PVA/CS film crosslinked by genipin. In vivo experiments indicate that the PVA/CS/mGO composite film can accelerate wound healing via enhancement of the re‐epithelialization. PVA/CS/mGO composite film with 0.5 wt% mGO sheets displays the best wound healing properties, as manifested by the 50% higher antibacterial rate compared to GO and the wound healing rate of the mouse using this dressing is about 41% faster than the control group and 31% faster than the pure PVA/CS dressing. The underlying mechanism of the accelerated wound healing properties may be a result of the improved antibacterial ability to eradicate pathogenic bacteria on the wound area and maintain an appropriate moist aseptic wound healing environment to accelerate re‐epithelialization. These findings suggest that this novel composite PVA/CS/mGO film may have promising applications in wound dressing.     

Ornidazole-loaded graphene paper for combined antibacterial materials

Excellent antibacterial property of graphene oxide makes it an important antibacterial material. However, in some cases, a synergistic combination of materials with different antibacterial mechanisms is desired. In this work, we developed a simple two-step protocol to prepare ornidazole (ONZ), a nitroimidazole antiprotozoal drug, loaded graphene-based paper for combined antibacterial materials. Graphene oxide (GO) and reduced graphene oxide (rGO) were used as carriers in antibacterial materials. After mixed with ONZ directly in aqueous media and filtrated under vacuum, the freestanding GO/ONZ and rGO/ONZ were peeled off from the filtrate membrane. The ONZ loading contents in the paper was determined by UV/vis spectroscopy and the surface properties were investigated by measuring their contact angle, which will have an important impact on the antibacterial effects of the papers.     

Permselectivity of Electrodeposited Polydopamine/Graphene Composite for Voltammetric Determination of Dopamine

A novel permselective film of electrodeposited polydopamine (PDA) on electrochemical reduced graphene oxide (erGO) surface was prepared. The obtained composite films were characterized by atomic force microscope (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influences of permselectivity with different electropolymerized cycles and concentration of dopamine on electrochemical responses of biomolecules on electrode were investigated. It was found that the composite film held high cationic permeable to dopamine (DA) and good suppression of ascorbic acid (AA) and uric acid (UA) using CV. The anodic peak currents were proportional to dopamine concentration. The significant permselectivity suggested that the PDA/graphene‐modified electrode has opened a new route to high selective dopamine biosensor.     

Activated carbon/graphene composites with high-rate performance as electrode materials for electrochemical capacitors

Glucose-derived activated carbon (GAC)/reduced graphene oxide (RGO) composites are prepared by pre-carbonization of the precursors (aqueous mixture of glucose and graphene oxide) and KOH activation of the pyrolysis products. The effect of the mass ratio of graphene oxide (GO) in the precursor on the electrochemical performance of GAC/RGO composites as electrode materials for electrochemical capacitors is investigated. It is found that the thermally reduced graphene oxide sheets serves as a wrinkled carrier to support the activated carbon particles after activation. The pore size distribution and surface area are depended on the mass ratio of GO. Besides, the rate capability of GAC is improved by the introduction of GO in the precursor. The highest specific capacitance of 334 F g^?1 is achieved for the GAC/RGO composite prepared from the precursor with a GO mass ratio of 3 %.     

Selective and sensitive determination of dopamine by composites of polypyrrole and graphene modified electrodes

A novel method is developed to fabricate the polypyrrole (PPy) and graphene thin films on electrodes by electrochemical polymerization of pyrrole with graphene oxide (GO) as a dopant, followed by electrochemical reduction of GO in the composite film. The composite of PPy and electrochemically reduced graphene oxide (eRGO)-modified electrode is highly sensitive and selective toward the detection of dopamine (DA) in the presence of high concentrations of ascorbic acid (AA) and uric acid (UA). The sensing performance of the PPy/eRGO-modified electrode is investigated by differential pulse voltammetry (DPV), revealing a linear range of 0.1-150 μM with a detection limit of 23 nM (S/N = 3). The practical application of the PPy/eRGO-modified electrode is successfully demonstrated for DA determination in human blood serum.     

Reduced graphene oxide/iron oxide hybrid composite material as an efficient magnetically separable heterogeneous catalyst for transfer hydrogenation of ketones

Reduced graphene oxide was synthesized and functionalized with FeSO₄⋅7H₂O to form a reduced graphene oxide/iron oxide hybrid composite. The hybrid composite was extensively characterized using various techniques. Its application for transfer hydrogenation of various ketones was studied. The investigation showed that it serves as a good catalyst for transfer hydrogenation of aromatic and some aliphatic ketones resulting in excellent isolated yields (97–99%) of products. It is magnetically separable showing good reusability. The products were characterized and compared with authentic ones.     

Sodium 1‐Naphthalenesulfonate‐Functionalized Reduced Graphene Oxide Stabilizes Silver Nanoparticles with Lower Cytotoxicity and Long‐Term Antibacterial Activity

Silver nanoparticles (AgNPs) are increasingly used in daily life for their antibacterial properties, but their low stability and high cytotoxicity hamper practical applications. In this work, sodium 1‐naphthalenesulfonate‐functionalized reduced graphene oxide (NA‐rGO) was used as a substrate for AgNPs to produce a AgNP‐NA‐rGO hybrid. This hybrid showed substantially higher antibacterial activity than polyvinyl pyrrolidone(PVP)‐stabilized AgNPs, and the AgNPs on NA‐rGO were more stable than the AgNPs on PVP, resulting in long‐term antibacterial effects. More importantly, this hybrid showed excellent water solubility and low cytotoxicity, suggesting the great potential application as sprayable reduced graphene oxide based antibacterial solutions.