Amine-functionalized graphene oxide/zinc hexacyanoferrate composites for cesium removal from aqueous solutions

Journal of Radioanalytical and Nuclear Chemistry - Amine-functionalized graphene oxide/zinc hexacyanoferrate (amino-rGO/ZnHCF) composites were successfully synthesized for the removal of Cs+ from...     

Simulation and synthesis of graphene oxide from expanded graphite

Russian Journal of General Chemistry - Expanded graphite oxide and multilayered graphene oxide have been synthesized. The processes of thermal expansion of intercalated graphite and oxidation of...     

Epoxide composites with thermally reduced graphite oxide and their properties

The properties of epoxide composites modified by thermal reduced graphite oxide are studied. The dielectric permittivities of epoxide composites with additives of up to 1.5 wt % of reduced graphite oxide are studied at a frequency of 9.8 GHz. It is shown that despite its low electrical conductivity, the large specific surface area of reduced graphite oxide allows us to create epoxide composites with high complex dielectric permittivities and dielectric loss tangents.     

Corrosion behaviour of zinc coated with composite silica layers incorporating poly(amidoamine)-modified graphene oxide

Journal of Solid State Electrochemistry - The aim of the paper is to carry out a detailed investigation of the effect of graphene oxide-poly(amidoamine) (GO-PAMAM) incorporated in silica matrices...     

Adsorption of ammonia on graphite oxide/aluminium polycation and graphite oxide/zirconium-aluminium polyoxycation composites

Graphite oxide (GO) synthesized from commercial graphite was modified with aluminium or zirconium-aluminium polyoxycations and then calcined at 350 degrees C. On the samples obtained adsorption of ammonia from moist air was investigated. The surface of materials before and after exposure to ammonia was characterized using adsorption of nitrogen, XRD, SEM, FTIR, TA, CHN analysis, and potentiometric titration. The results showed that in spite of the fact that graphite composites/pillared graphites (PG) have Keggin-like ions located between the layers, that space blocked for nitrogen molecules used to determine the specific surface area. During calcinations, the deflagration of layers occurred as a result of decomposition of epoxy groups. This results in formation of disordered graphitic carbons with some mesoporosity. Even though these materials were not porous, the significant amount of ammonia was retained on the surface. Since ammonia molecule is able to specifically interact with oxygen groups of graphite oxide and Br?nsted centers of inorganic pillars, it is likely intercalated between the composite layers. While the best performance was found for GO modified with aluminium-zirconium species, after calcinations the samples containing Keggin Al(13) like cations revealed the high capacity which is linked to the high acidity of incorporated inorganic compounds.     

Boosting overall water splitting by incorporating sulfur into NiFe(oxy)hydroxide

Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is a significant challenge for overall water splitting.Sulfur-incorporated nickel iron(oxy)hydroxide(S-NiFeOOH) nanosheets were directly grown on commercial nickel foam using a galvanic corrosion method and a hydrothermal method.The incorporation of sulfur into NiFeOOH enhanced the catalytic activity for the HER and OER in 1 M KOH electrolyte.The enha...     

Phase transformations of the nanosize zinc hydroxide and oxide particles

The structure and properties of zinc hydroxide and oxide nanoparticles obtained by chemical and combined means were studied by transmission electron microscopy, X-ray phase, thermal analysis, and atomic emission spectroscopy. The effect of the synthesis conditions on the formation structure and morphology of nanoparticles was studied. It was shown that the electric field effect on a solution allows us to obtain almost single-phase systems with a narrower range of the particle sizes than in the case of chemical deposition.     

Microwave-assisted synthesis of CdS-reduced graphene oxide composites for photocatalytic reduction of Cr(VI)

CdS-reduced graphene oxide (RGO) composites are successfully synthesized via the microwave-assisted reduction of graphite oxide in a CdS precursor solution using a microwave synthesis system. The photocatalytic performances of CdS-RGO composites in the reduction of Cr(VI) are investigated. The results show that CdS-RGO composites exhibit enhanced photocatalytic performance for the reduction of Cr(VI) with a maximum removal rate of 92% under visible light irradiation as compared with pure CdS (79%) due to the increased light absorption intensity and the reduction of electron-hole pair recombination in CdS with the introduction of RGO.     

石墨烯/锌铁氧体复合物的制备及抗菌性能

用氧化还原法和化学共沉淀法分别制备了石墨烯(GE)和石墨烯/锌铁氧体(GE/ZnFe2O4)复合物,通过现代测试技术表征了样品的物相结构、组成和微观形貌.以大肠杆菌、金黄色葡萄球菌和白色念珠菌为测试菌种,分别对样品的抗菌性能进行了研究.结果表明,样品的抗菌活性受GE/ZnFe2O4复合物中GE和ZnFe2O4质量比(mG/Z)以及菌种的影响,其中mG/Z=0.4的复合物对三种菌均有较好的抗菌效果,其最小抑菌浓度分别为25、25和12.5μg/mL;复合物对白色念珠菌的抗菌效果最好,这与菌种的结构有关.此外,对样品的抗菌机理进行了详细研究.     

Photochemical and thermal behaviours of poly(vinyl alcohol)/graphite oxide composites

The properties of poly(vinyl alcohol)/graphite oxide (PVAL/GO) composites were investigated during UV irradiation using a mercury lamp (λ = 254 nm). The course of photochemical reactions was monitored by FTIR and UV-vis absorption spectroscopies as well as by estimation of insoluble gel amount formed during crosslinking. Changes in average molecular weights resulting from main chain scission in PVAL were measured by gel permeation chromatography. Composite microstructure was characterized by scanning electron microscopy and X-ray diffraction. The thermal behaviour of composites was determined by a thermogravimetric analysis. It was found that 0.1-5.0% GO addition to polymer bulk slightly hampers photooxidative degradation of PVAL. Thermal degradation in PVAL composites starts at somewhat lower temperatures in the presence of GO but this trend is changed in UV-irradiated samples.     

Preparation and characterization of modified graphite oxide/poly(propylene carbonate) composites by solution intercalation

Modified graphite oxide (MGO)/Poly (propylene carbonate) (PPC) composites with excellent thermal and mechanical properties have been prepared via a facile solution intercalation method. An intercalated structure of MGO/PPC composites was confirmed by X-ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer-sized dispersion of layered graphite in PPC matrix and the strong interfacial interaction between MGO and PPC, the prepared MGO/PPC composites exhibit improved thermal and mechanical properties in comparison with pure PPC. Compared with pure PPC, the MGO/PPC composites show the highest thermal stability and the T_g is 13.8 °C higher than that of pure PPC, while the tensile strength (29.51 MPa) shows about 2 times higher than that of pure PPC when only 3.0 wt.% MGO is incorporated. These results indicate that this approach is an efficient method to improve the properties of PPC.     

Charge storage characteristics of layer-by-layer assembled nickel hydroxide and graphene oxide nanosheets

Journal of Solid State Electrochemistry - In this study, layer-by-layer assembled thin films composed of nickel hydroxide and graphene oxide nanosheets were produced via simple dip coating process....     

金负载氧化石墨烯/PDPB复合材料用于同步去除六价铬离子和苯酚

近年来,电镀和染料行业工业废水中排放的有机污染物和重金属离子严重危害着环境.构建无机-有机新型纳米材料用于光催化去除重金属离子和有机污染物受到了广泛的关注.共轭聚合物因其低廉的制造成本,快速的电子传送能力,优秀的电化学性能和高的机械性能,它们作为一类新能源材料已经快速发展起来.Remita等使用软模板方法制备的一种共轭聚合物聚1,4-二苯基丁二炔(PDPB)在可见光下对苯酚表现出较好的去除率.然而,聚合物PDPB的一些缺陷限制了其应用,比如高的疏水特性和快速的光生电子-空穴复合.因此,我们引入氧化石墨烯(GO)和金纳米粒子来提高PDPB的光催化活性.通过简单的机械搅拌和光还原方法制备了Au-GO/PDPB复合材料.通过TEM,XRD,XPS,固体紫外和光电流测试等技术对催化剂进行了一系列表征,结果发现氧化石墨烯作为优秀的电子传送基地,金纳米粒子作为电子捕获剂,在空间上实现了电子空穴的空间隔离,从而大大提高了Au-GO/PDPB复合材料对于六价铬离子和苯酚的同步光去除的光催化活性.XPS表征和TEM图像表明了GO和Au纳米粒子的存在.其PDPB有着纳米纤维的结构,宽度在20 nm左右,长度在几个微米.当复合了氧化石墨烯后,可以明显看出氧化石墨烯的形态,进一步光还原负载金纳米粒子,同样可以在TEM图中观察到金纳米粒子的存在,其直径在10 nm左右.之后通过光催化同步去除六价铬离子和苯酚来探究Au-GO/PDPB复合材料的活性,结果表明所制备的Au-GO/PDPB比纯的PDPB有着增强的光催化活性在同步光去除六价铬离子(Cr(VI))和苯酚中.更进一步地是,我们同样确定了GO和Au纳米离子的最佳负载量,结果发现,Au1-GO2/PDPB复合材料(金的负载量为1 wt%,氧化石墨烯的负载量为2 wt%)在所有催化剂中有着最好的光催化活性,其在4 h内对苯酚的去除率达到49.4%,相应的对于六价铬离子的还原率达到了77.4%.我们的研究提供了一种构建有机-无机杂化复合材料的方法,其在太阳光下对于有机污染物和重金属离子的同步去除有着高的光催化活性.     

Adsorption of Zn(II) on graphene oxide prepared from low‐purity of amorphous graphite

The adsorption of Zn(II) in aqueous solutions on graphene oxide (GO) prepared from low‐purity of natural amorphous graphite has been studied in this work. The study was performed through the measurements of Zeta potential, atomic force microscope, Fourier transform infrared spectrum and X‐ray photoelectron spectroscopy. The results indicated that the adsorption followed the Langmuir model with the maximum Zn(II) adsorption capacity of 73 mg/g at pH 7.0. In addition, the adsorption was well described by the pseudo‐second‐order kinetics model. The mechanism of the Zn(II) adsorption on GO was mainly attributed to chemical adsorption through complexation reaction between Zn(II) and hydroxyl or carboxyl groups on the GO sheets, while the electrostatic interaction also contribute to the whole interaction. Copyright © 2016 John Wiley & Sons, Ltd.     

Kinetic peculiarities of the reaction of liquefied hydrogen sulfide with propylene oxide

The kinetics of the liquid-phase reaction of hydrogen sulfide with propylene oxide was studied. In the presence of excess epoxide, the reaction occurred in two successive macrostages: (1) formation of 2-hydroxypropane-1-thiol and (2) formation of 1,1′-di(2-hydroxypropyl) sulfide. Both of the stages are autocatalytic. 2-Hydroxypropane-1-thiol was mainly formed in the presence of excess H₂S. The overall third order of the reaction (the first with respect to each reagent and to 2-hydroxypropane-1-thiol) was found. A kinetic scheme was proposed, and the rate constants of particular stages were calculated. The influence of various catalysts (active carbon, ion-exchange resins, metal oxides, and others) was studied, and the relative efficiency of some of them was determined. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1083–1089, June, 1999.     

Retracted: EMI shielding effectiveness of expanded graphite and reduced graphene oxide

Retraction: Gairola, SP, Gairola, P, Shah, SK, Gupta, R. EMI shielding effectiveness of expanded graphite and reduced graphene oxide. J. Chin. Chem. Soc. 2018. https://doi.org/10.1002/jccs.201800189 . The above article, published online on 1 October 2018 in Wiley Online Library ( https://onlinelibrary.wiley.com ), has been retracted by agreement between the corresponding author, the journal's Editor‐in‐Chief, Dr. Yu‐Tai Tao, the Chemical Society Located in Taipei, and Wiley‐VCH Verlag GmbH & Co. KGaA. The retraction has been agreed due to several images across Figures 1, 2 and 3 within the article having been duplicated from other publications. The corresponding author apologizes for the inconvenience caused.     

Fabrication and physicochemical characterization of graphene oxide derived from thermally expanded graphite

Graphene oxide was obtained from expanded graphite according to the modified Hummers method. The reaction time was significantly reduced (from 24 to 8 h) by applying the expanded graphite in the oxidation process. The interlayer distance in obtained samples was equal to 0.70–0.74 nm. Structural features of the material were studied by the powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, XPS spectroscopy, and NMR spectroscopy.     

Topotactically constructed nickel-iron (oxy)hydroxide with abundant in-situ produced high-valent iron species for efficient water oxidation

The low efficiency of oxygen evolution reaction (OER) is regarded as one of the major roadblocks for metal-air batteries and water electrolysis.Herein,a high-pe...