Self-assembled monolayers of stearic imidazoline on copper electrodes detected using electrochemical measurements, XPS, molecular simulation and FTIR

A type of imidazoline inhibitor was synthesized using stearic acid and diethylenetriamine (DETA) as raw materials. Self-assembled monolayers (SAMs) of stearic imidazoline (IM) were prepared on copper surface. The copper electrode modified by IM was detected by electrochemical impedance spectros-copy (EIS),Tafel polarization curves, X-ray photoelectron spectroscopy (XPS) and Fourial transform reflection spectroscopy (FTIR). The biggest inhibition efficiency for copper corrosion of IM was 99% in NaCl solution according to EIS results. The XPS results provided evidence that the IM was adsorbed on copper surface. The theoretical calculations of molecular simulation supported the experimental re-sults and showed that the IM molecules were tilted at an angle to the copper surface.     

Functionalized graphene oxide based on p-phenylenediamine as spacers and nitrogen dopants for high performance supercapacitors

p-Phenylenediamine （PPD） functionalized graphene oxide （GO） materials （PPDG） were prepared through a one-step solvothermal process and their appli-cation as supercapacitors （SCs） were studied. The PPD is not only as the spacers to prevent aggregating and re-stacking of the graphene sheets in the preparing process but also as nitrogen sources to obtain the nitrogen-doped graphene. The structures of PPDG were characterized by Fourier transformed infrared spectroscopy （FT-IR）, X-ray diffraction spectroscopy （XRD）, Raman spectroscopy and X-ray photoelectron spectroscopy （XPS） and the results show that the nitrogen-doped graphene was achieved with nitrogen content as high as 10.85 at.%. The field emission scanning electron microscopy （FE-SEM） and high resolu-tion transmission electron microscopy （HR-TEM） have confirmed that the morphologies of PPDG were looselayered with less aggregation, indicating that PPD mole-cules, as spacers, effectively prevent the graphene sheets from restacking during the solvothermal reaction. The special loose textures make PPDG materials exhibit excellent electrochemical performance for symmetric SCs with superior specific capacitance （313 F/g at 0.1 A/g）, rate capability and cycling stability. The present synthesis method is convenient and may have potential applications as ultrahigh performance SCs.     

Mesoporous iron oxide-silica supported gold catalysts for low-temperature CO oxidation

Mesoporous iron oxide-silica composite with a high silica content was synthesized by hydrothermal method, and another composite material with a high iron content was obtained by etching part of silica in alkaline solution. Gold catalysts were loaded onto both composites by a deposition-precipitation method, and used for CO oxidation. The samples were characterized by Brumauer- Emmet-Teller （BET）, X-ray diffraction （XRD）, X-ray photoelectron spectra （XPS）, transmission electron micro- scope （TEM） and scanning electron microscope （SEM） techniques. Both composites had high specific surface areas and were amorphous. The Au nanoparticles dispersed on the surface of the composites existed in metallic state. Composite with high silica content was not suitable for Au loading, and its supported gold catalyst showed poor per- formance in catalytic reaction. In contrast, composite with high iron content allowed efficient Au loading, and CO could be oxidized completely at low temperature on its supported gold catalyst. The effects of deposition-precipi- tation pH values on Au loading and activity of the catalyst were investigated, and the results indicated that Au loading was the highest and the catalyst was the most active for CO oxidation when the synthesis pH was adjusted to 8.     

Pepsin nanofilm self—assembly on the positively charged poly （ethylene terephthalate）substrate

Pepsin was assembled on the surface of prepared poly(ethylene terephthalate)(PET-NH3^ ) substrates.The composition and structure of the pepsin/PET-NH3^ assembling films in different condition were characterized by X-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM).     

Preparation and Application of Water Dispersible Graphene as Antistatic Agent for SMS Nonwovens

In this paper, glucose was used as a green reducing agent and a capping reagent in the synthesis of water dispersible graphene, while using exfoliated graphite oxide （GO） as the precursor with the modified Hummers method. Characterizations of the graphene were conducted by UV-visihle absorption spectroscopy and X-ray diffraction （XRD）. Then the spunlaid-melthlowing-spuulaid （SMS） nonwovens were treated with the graphene solution via pad-dry-cure process. The surface and the antistatic property of the obtained nonwovens were tested. The results showed that O. 1 mg/mL graphene solution exhibited good stability in water. When treated with this solution, the graphene could be evenly dispersed on SMS nonwovens and the nonwovens had an excellent antistatic performance and a high relatively antistatic durability.     

Immobilization of biomacromolecules on poly-L-lactide surface via a layer-by-layer method for the improving of its cytocompatibility to bone marrow stromal cells

Hyaluronic acid （HA） and chitosan （CS） were immobilized on the surface of poly-L-lactide （PLLA） by the following procedure： Firstly, PLLA was aminolyzed with 1, 6-hexanediamine, and part of the PLLA surface ester groups were converted to free amino groups. Then negatively charged hyaluronic acid and positively charged chitosan were deposited onto the surface of aminolyzed PLLA film in a layer-by-layer assembly manner. The effect of the layer-by- layer deposition was evaluated by ATRoFTIR spectroscopy, Raman spectroscopy and static contact angle measurements. The cytocompatibility of PLLA sample to bone marrow stromal cells （BMSCs） was improved after modification with chitosan and HA. The cell attachment, activity, and proliferation on CS/HA modified PLLA films were enhanced comparing with the control. The cells cultured on the modified PLLA samples excreted abundant cytoplasm and can differentiate to vascular smooth muscle （SM）-like （SM-like） cells. A macroporous three-dimensional PLLA scaffold was prepared by integrating both the technique of freeze-drying and particle leaching. Layer-by-layer modification by HA/CS and cell culture was also applied on this scaffold. The scaffold cultured with BMSCs for 2 weeks has been tested successfully in vivo as a patch for repairing the artificial incision on canine pulmonary artery.     

Preparation of TiO2 Coated on Fabrics and Their Photocatalytic Reactivity

Nanoscale titanium dioxide functional films were prepared on the surface of the cotton woven fabric and the polyester knitted fabric at room temperature by Radio Frequency （RF） magnetron sputtering process. The surface microstructure and morphology were characterized by scanning electron microscope （SEM） and X-ray diffraction （XRD）. Photocatalytic property of two treated fabrics was tested in solar and ultraviolet （UV） radiation respectively, and their photocatalytic activity was compared. The results showed that the nanoscale titanium dioxide deposited on the surface of the treated fabrics was at different anastasia phase. The treated fabrics have excellent photocatalytic property, and after 30 launderings, the photocatalytic activity still maintained at a high level. Also, it indicated that the photocatalytic activity of the treated fabrics in UV radiation was higher than in solar radiation, but the effect wasn＇t very distinct. And at the same experimental magnetron sputtering parameters, the cotton coated with the nanoscale titanium dioxide showed better performance than the polyester fabric coated with the nanoscale titanium dioxide in terms of the photocatalytic property.     

Effect of solvent on Se-modified ruthenium/carbon catalyst for oxygen reduction

Se-modified ruthenium supporting on carbon(Sex–Ru/C) electrocatalyst was prepared by solvothermal one-step synthesis method. The reaction mechanism was revealed after discussing impact of different solvents(i-propanol and EG) in solvotermal reaction. The result showed that the grain size of Se-modified ruthenium electrocatalyst was as small as 1 to 3 nm and highly dispersed on carbon surface. X-ray photoelectron spectroscopy(XPS) presented that selenium mainly existed in the catalyst in the form of elemental selenium and selenium oxides when the solvent was EG and i-propanol, respectively. The oxygen reduction reaction(ORR) performance was improved by appearance of selenium oxides.     

Enhanced Removal of Tetracycline from Aqueous Solution by Graphene Oxide Hydrogel Doped with TiO_2 Nanotubes

The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,which posed a challenge to the conventional techniques. In this work,the batch experiments on TC adsorption in aqueous solution of hydrogel( HG) consisting of graphene oxide( GO) and TiO_2 nanotubes( TN) were successfully conducted. HG composite( HG-TN-GO) was prepared with TN and GO with self-assembly method during the oxidation-reduction reaction,and criogel( CG) with TN and GO was characterized by pH at point of zero charge( pH_(pzc)), transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy( XPS). The adsorption capacity of HG-TN-GO on TC was evaluated by analyzing its isotherms. The maximum adsorption capacity reached 751. 3 mg/g. Besides,the adsorption isotherms were well fitted by the Langmuir model, with the theoretical maximum( q_m) of 797. 0 mg/g. The adsorption process was systematically studied by varying pH during the whole adsorption process. The adsorption occurred probably via π-π interaction and cation-π bonding between TC and the HG-TN-GO surface. The composite could be regenerated in 50% ethanol aqueous solution,without significant capacity loss. After 6 recycles,the decrease of adsorption capacity was less than 10%.     

Corrosion properties of bio-oil and its emulsions with diesel

Bio-oil is a new liquid fuel but very acidic. In this study, bio-oil pyrolyzed from rice husk and two bio-oil/diesel emulsions with bio-oil concentrations of 10 wt% and 30 wt% were prepared. Tests were carried out to determine their corrosion properties to four metals of aluminum, brass, mild steel and stainless steel at different temperatures. Weight loss of the metals immersed in the oil samples was recorded. The chemical states of the elements on metal surface were analyzed by X-ray photoelectron spectroscopy （XPS）. The results indicated that mild steel was the least resistant to corrosion, followed by aluminum, while brass exhibited slight weight loss. The weight loss rates would be greatly enhanced at elevated temperatures. Stainless steel was not affected under any conditions. After corrosion, in- creased organic deposits were formed on aluminum and brass, but not on stainless steel. Mild steel was covered with many loosely attached corrosion materials which were easy to be removed by washing and wiping. Significant metal loss was detected on surface of aluminum and mild steel. Zinc was etched away from brass surface, while metallic copper was oxidized to Cu20. Increased Cr203 and NiO were presented on surface of stainless steel to form a compact passive protection film. The two emulsions were less corrosive than the bio-oU. This was due to the protection effect of diesel. Diesel was the continuous phase in the emulsions and thus could limit the contact area between bio-oil and metals.     

A novel heteroseneous reaction for generating gaseous nitrous acid

The short-lived reactive specimen nitrous acid HONO was generated in the gas phase by the heterogeneous reaction of gaseous HCl with AgNO2 which can generate higher concentration of HONO than other methods. We investigated the process from generation to dissociation in the gas phase under different controlled temperatures, and discussed the ionization and reaction on the solid surface by combination of the photoelectron spectroscopy and photoionization mass spectroscopy （PES-PIMS） and in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）.     

Ag/reduced graphene oxide(RGO) nanocomposites for detection of TNT

The modified Hummers method was employed to generate graphene oxide, and Ag/reduced graphene oxide (RGO) nanocomposites were synthesized at different temperatures by using sodium citrate as the reductant. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were employed to characterize the reaction products. The results indicate that RGO has been synthesized successfully, and Ag particles are distributed evenly on the surface of RGO. The RGO prepared at a reaction temperature of 120℃ shows the best surface-enhanced Raman scattering (SERS) activity. The Ag/RGO nanocomposites modified by 10^-5 mol/L 4-aminothiophenol (PATP) successfully detect a 10^-5 mol/L 2,4,6-trinitrotoluene (TNT) alcohol solution.     

Ru(0001)和(1010)表面上NH_3吸附结构研究

利用密度泛函理论,在slab模型下,研究NH3在Ru表面的吸附行为.结果表明,NH3在Ru(0001)和Ru(1010)面上的优势吸附位皆为顶位.NH3的吸附是化学吸附且具有表面结构敏感性,与密堆积表面(0001)相比,NH3在开放的(1010)面上的吸附更加稳定,吸附能达到1.08 eV.电子结构计算结果表明,NH3通过其3a1轨道与表面Ru原子的4dz2和5s态混合吸附于表面.     

Preparation and characterization of 3-(triethoxysilyl) propyl isocyanate self-assembled monolayer on surface of chip

Monolayer of 3-(triethoxysilyl) propyl isocyanate was prepared on the slide by self-assembled tech-nique. X-ray photoelectron spectroscopy (XPS) was employed to analyze the elementary composition of the film. Contact angle of distilled water was measured to characterize the surface state. It was shown that 3-(triethoxysilyl) propyl isocyanate had been successfully assembled on the slide. The in-crease of contact angle to 80° demonstrated that the hydrophobicity of the surface of chip was in-creased signific...     

超临界乙醇制备TiO2/石墨烯纳米复合材料及其表征

以氧化石墨为载体、钛酸异丙酯为前驱体,利用超临界乙醇的超临界性能和还原性,制得了晶型完善的锐钛矿TiO2/石墨烯纳米复合材料.通过红外光谱（FTIR）、X射线光电子能谱（XPS）对采用Hummers法制得的氧化石墨（GO）进行表征;同时利用透射电子显微镜（TEM）、X射线衍射仪（XRD）对TiO2/石墨烯纳米复合材料进行研究.结果表明：成功制得了氧化石墨（GO）和晶型完善的锐钛矿TiO2/石墨烯纳米复合材料,并且发现二氧化钛在石墨烯纳米片层上呈现为有规则的颗粒,分散均匀,平均粒径为8.24 nm.     

Mn掺杂纳米晶ZnO的制备及其性质

 采用固相热分解自组装方法制备Mn掺杂纳米晶ZnO样品, 并利用X射线衍射(XRD)、 能量散射光谱(EDS)、 X射线光电子能谱(XPS)和光致发光光谱(PL)等方法测试Mn掺杂ZnO样品的结构、 形态及光学性质. 结果表明: 采用本文方法获得了具有ZnMn低O/ZnMn高O核壳结构的ZnMnO合金; 在250 ℃和300 ℃制备样品时, 表面存在大量的Mn对表面起钝化作用.     

氮掺杂石墨烯的制备及其氧还原电催化性能

以三聚氰胺和氧化石墨烯(GO)为原料,经物理研磨和高温热解得到氮掺杂石墨烯(三聚氰胺-NG).扫描电子显微镜(SEM)测量显示,所制备的三聚氰胺-NG厚度和表面褶皱较掺杂前略有增加.X射线光电子能谱(XPS)表明,在三聚氰胺-NG中氮元素以吡咯N、吡啶N和石墨N 3种形式掺杂在石墨烯中,它们的比例分别是14.5%、24.5%和61.0%.同时运用循环伏安法(CV)和旋转圆盘电极技术(RDE)测试了三聚氰胺-NG在碱性介质中的氧还原电催化活性.结果表明,与商业石墨烯和由聚吡咯为氮源制备的氮掺杂石墨烯(ppy-NG)相比,三聚氰胺-NG具有较高的电催化活性和较正的氧还原起始电位(-0.09V),并且电催化还原氧气时主要为4电子反应.由于其较高的氧还原性能和较低的成本,三聚氰胺-NG在碱性燃料电池阴极电催化剂中有良好的应用前景.