NANOSTRUCTURING PLATINUM NANOPARTICLES ON NI/CE0.8GD0.2O2-δ ANODE FOR LOW TEMPERATURE SOLID OXIDE FUEL CELL VIA SINGLE-STEP INFILTRATION: A CASE STUDY

Large‐scale high‐quality BaMoO4 nanocrystals have been synthesized in aqueous solutions under mild conditions with citrate as a simple additive. The crystals have bone‐like, spindle‐like and wheatear‐like morphologies assembled from nanoparticles, nanofibers and have been characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. The results showed that experimental parameters had great influences on the shape evolution of products. The adjustment of these parameters such as room temperature stirring time, reaction temperature and reaction time of hydrothermal reaction, can lead to obvious morphology changes of products, and the growth mechanism has been proposed. Room‐temperature photoluminescence indicated that the as‐prepared BaMoO4 nanocrystals had a strong blue emission peak at 481.5 nm. This facile route could be employed to synthesize more promising nanomaterials with interesting self‐assembly structures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Epoxidized natural rubber (ENR) / silica (Si) organic-inorganic composites were prepared by using a sol-gel technique. The choice of ENR (50 mol % epoxidation level), as a matrix was made because of its polar nature which can interact with the silica. The processing of the masterbatch was carried out by sol-gel method at room temperature by dispersing the silica in the rubber and coagulated with steam bath. The performance of the composites was evaluated in this work for the viability of ENR/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. Silica was also efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers. Improvement in tensile strength over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the rubber phase.

The T-derived subset of human peripheral blood normal lymphocytes has been selected as a model system to study the usefulness of 5 nm gold markers for quantification of single epitopes expressed on cell surfaces. The chosen epitopes are parts of the CD3 and CD5 molecules and can be specifically identified by hybridoma produced monoclonal antibodies (MoAbs; LEU-4 and LEU-1; Becton-Dick- inson, Mountain view, CA) . An indirect immunolabeling procedure, with goat anti-murine IgG adsorbed on the surface of 5 nm colloidal gold particles (GAM-G5, Janssen Pharmaceutica, Beerse, Belgium) has been used. Backscattered Electron Imaging (BEI) in a field emission scanning electronmicroscope (SEM) and transmission electron microscopy of thin sections of lymphocytes labeled before plastic embedding, were both used to identify and quantitate gold labeled cell surface sites, Estimating that the thickness of “silver” sections is approximately 60 nm and counting the number of gold particles on the entire cell perimeter, we calculated that, for LEU-4, the number of markers per um2 of cell surface is in the 140-160 range (Fig.l). Cell contour length measurements indicated that the surface of one lymphocyte is approximately 130-160 um2 that of a smooth sphere of identical diameter, reflecting the role of microvilli in expanding the surface area. The total number of gold labeled sites on the surface of one lymphocyte averages, therefore between 20,000 and 24,000 per cell.

In recent years, dye-sensitized solar cells (DSSCs) have attracted much attention because of their easy fabrication, good flexibility low cost and relatively high efficiency. As a crucial component, the function of counter electrode (CE) is to collect the electrons from external circuits and transfer them to electrolyte by catalyzing the reduction of I3- into I-. Platinum (Pt) is a conventional material of CE in DSSCs due to its high conductivity and outstanding catalytic activity towards the reduction of triiodide (I3-). However, the high cost and low abundance of Pt restrict the commercial application of DSSCs. Moreover, Pt could be dissolved slowly in the I-/I3- redox electrolyte, which will deteriorate the long term stability of DSSCs. Therefore, it is necessary to explore novel material with high conductivity, catalytic activity and stability to replace Pt. In this paper, with Fe(NO3)39H2O and graphene oxide (GO) serving as raw materials and deionized water as the solvent, we synthesize iron diselenide (FeSe2) nanorods (with diameters in a range of about 100-200 nm)/reduced graphene oxide (rGO) composite through a facile hydrothermal method and use the composite as CE material of DSSCs for the first time. The structure and morphology of FeSe2/rGO are characterized by using X-ray diffraction (XRD), Raman spectrum, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The XRD pattern shows that the FeSe2 is typically orthorhombic phase. The SEM images show that the FeSe2 has a structure of nanonods and can be attached to the surface of rGO closely The surface of FeSe2/rGO composite is rough and exhibits a porous structure. The TEM image shows that the FeSe2 has a high degree of crystallinity and orientation. To evaluate the catalytic activity and conductivity of FeSe2/rGO, we perform cyclic voltammetry (CV) measurements, electrochemical impedance spectroscopy and obtain Tafel polarization curves for FeSe2/rGO electrode and also for Pt, FeSe2 and rGO electrodes for comparison. The results indicate that the CE based on FeSe2/rGO composites has the lowest peak-to-peak voltage separation (E_{pp}) charge transfer resistance (Rct) and series resistance (Rs) in the four different CEs, suggesting that the FeSe2/rGO CE has an excellent electrocatalytic performance for the reduction I3-. The current density-voltage (J-V) curves of DSSCs with different CEs under the illumination of 1 sun (100 mW cm-2) show that the cell with FeSe2/rGO CE has an open-circuit voltage (Voc) of 0.727 V, a short-circuit current (Jsc) of 18.94 mA cm-2, a fill factor (FF) of 0.65 and an excellent power conversion efficiency (PCE) of 8.90%, which is a notable improvement compared with the PCE of the cell with an FeSe2 CE (7.91%) and an rGO CE (5.24%). It can be attributed to the synergetic effects between the FeSe2 nanorods and rGO which eventually improve the PCE of DSSC We also conducte the experiments on the electrochemical stability of FeSe2/rGO CE by sequential CV measurements the result indicates that the FeSe2/rGO composite has a better stability than Pt in I-/I3- electrolyte In summary, we synthesize a novel FeSe2/rGO conductive catalyst. This hybrid material possesses the features of FeSe2 and rGO, exhibiting both highly catalytic activity and high conductivity Therefore, the low-cost and high-performance FeSe2/rGO composite can be a promising CE material to replace Pt in the large-scale industrial production of DSSCs.

In this study tungsten trioxide has been synthesised as a thermal infrared (TIR) absorbent by sol–gel method and characterised by X-ray diffraction (XRD), field emission scanning electron microscopes (FESEM) and transmission electron microscopy (TEM). XRD analysis shows that the single phase and hexagonal tungstate was prepared. The crystallite size measured by Scherer formula is in good accordance with the crystallite nano size measured by TEM. The polyaniline (PANI) was coated on WO3/MnFe2O3 nanoparticles (NPs, 50/50 wt%) via in situ polymerisation by core-shell structure WO3/MnFe2O3/PANI nanocomposite (50% wt as core). Structural and morphological characteristics of the produced nanocomposite were studied via X-ray diffraction, Fourier transformation infrared spectroscopy and scanning electron microscopy. The electric property was also performed by four probe method. The results showed that the WO3/MnFe2O3/PANI nanocomposites have good electric property. The TIR absorption of nanocomposite was investigated at 10–40 µm frequencies. The TIR images testing showed that the ability of infrared thermal imaging was increased by increasing WO3/MnFe2O3 as core and independent to increasing PANI as final shell. The test microwave absorption properties of the nanoparticles powder dispersing in PANI and thickness of 1.5 mm were investigated by using a vector network analysers in the frequency range of 8–12 GHz. A minimum reflection loss of the nanocomposite reaches -12 dB were observed at 8.8 and 11.6 GHz, respectively.

The new synthesized sulfamic acid functionalized catalyst on the basis of calix[4]resorcinarene catalyzed successfully and efficiently the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives through a one-pot condensation reaction of β-naphthol with various aryl aldehydes under thermal solvent-free conditions. As the major advantages of the present method, solvent-free and mild acidic conditions, catalyst recyclability, easy purification of the products, high yields along with relatively less reaction times can be mentioned. IR spectroscopy, field emission scanning electron microscopy and transmission electron microscopy are some of the spectroscopic methods used to characterize the new synthesized solid support.

The fine structural characteristics of the antennal sensory organs of a female millipede Oxidus gracilis (Polydesmida: Paradoxomatidae) were observed with both field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). We could identify four apical cones and three basic types of antennal sensillae in O. gracilis as follows: chaetiform sensilla (CS), trichoid sensilla (TS) and basiconic sensilla (BS). Of these, both types of CS and TS can be observed throughout all antennal segments except the terminal 8th article, whereas the BS are observed within the cuticular depressed regions of the articles from the 5th to the 7th segment. According to their relative size, microstructure and location, the BS are divided further into three subtypes: large (BS1), small (BS2) and spiniform (BS3). The BS1 can be seen on the 5th article only, while BS2 can be seen on the 5th and 6th articles. The BS3 is characteristically seen within the depressive region of the 7th article. Both the CS and TS of O. gracilis are similar in structure, and they are related to the function of mechanical reception; however, four large apical cones (AP) and three subtypes of BS are likely to function in gustatory and olfactory reception.

M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were successfully prepared by the sol-gel method and solution phase reduction method, respectively. The crystalline and morphology of particles were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composite coatings with SrFe12O19 ferrites and FeNi3 nanoplatelets in polyvinylchloride matrix were prepared. The microwave absorption properties of these coatings were investigated in 2-18GHz frequency range. The results showed that the M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were obtained and they presented irregular sheet shapes. With the increase of the coating thickness, the absorbing peak value moves to the lower frequency. The absorbing peak values of the wave increase along with the increasing of the content of FeNi3 nanoplatelets filling fraction. When 40% SrFe12O19 ferrites is doped with 20% mass fraction FeNi3 nanoplatelets to prepare composite with 1.5mm thickness, the maximum reflection loss is -24.8 dB at 7.9GHz and the -10 dB bandwidth reaches 3.2GHz.

Ultraviolet-A (UVA) radiation is present in sunlight and have been associated with various types of human skin cancers. In this study, rubber-grade zinc oxide (ZnO) powder was used as the targeted materials to study its UVA photoresponse as well as its antibacterial function. ZnO powder was synthesized using French process. The morphological structures of the samples were investigated using field emission scanning electron microscopy and transmission electron microscopy. The dominant morphology of the sample was micro/nanoplate. The optical bandgap of the ZnO sample is 3.19 eV based on the UV-Visible measurement. Current-voltage measurement was conducted to study the effect of UVA (390 nm) illumination on the photoconductivity of the ZnO pellet. Photoconductivity was observed to increase significantly under UVA exposure due to light absorption on the surface of ZnO to raise the electrons across the bandgap. The current response of the UVA-induced also revealed the small persistent photoconductivity after the UVA light was turned off. Besides, higher voltage bias would lead to higher current flow under the same intensity of UVA exposure. According to the antibacterial test towards Staphylococcus aureus, the percentage inhibition of the bacterial after 24 h incubation increase when the concentration of ZnO suspension increases. The UVA illumination had improved the inhibition of the bacterial growth. This is due to the excitation of ZnO and increasing of free charge carriers in the solution, leading to potential distortion to the membrane surface of the bacteria. ZnO powder performed high absorption of UVA and they are not only can be used to block the UVA sunlight, but also have higher antibacterial capability under UVA excitation.

The flexible oriented one-dimensional (1-D) TiO2 nanocrystalline films with large length-diameter ratios were synthesized in 1 M NaOH solution by hydrothermal treatment of the thin titanium layer which was deposited on flexible stainless steel substrates by direct current magnetron sputtering. The films were characterized, respectively by field emission scanning electron microscopy (FESEM), X-Ray diffraction (XRD), and transmission electron microscopy (TEM). Results showed that the TiO2 films were composed of oriented single-crystalline anatase nanowires, and the morphology of the nanowire film was determined by hydrothermal conditions. The photoelectric property studies revealed that the photoelectric property of TiO2 films was improved with the increase of the hydrothermal temperature. This approach provides an alternative method to synthesize 1-D TiO2 nanocrystalline films on non-Ti substrates.

Zn-doped SnO2 seaflower like hierarchical architectures have been synthesized via a solvothermal synthesis route in the mixed solvents of ethanol and deionized water. The observations of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed that Zn-doped SnO2 seaflower like hierarchical architectures were assembled by the nanowires. The preferential growth direction of nanowires was determined based on the analysis of high resolution transmission electron microscopy (HRTEM). The products were also characterized by X-ray diffraction (XRD) and X-photoelectron spectrum (XPS), and the results indicated that Sn4+ ions were successfully substituted by Zn2+. The photocatalytic activity of Zn-doped SnO2 seaflower like hierarchical architectures was evaluated by the degradation of RhB aqueous solution and the results showed that the product had high photocatalytic activity efficiency.

A facile method for rapid preparation of individual titania nanotube powders by a two-step process

Al206-5 pct aluminap cast composites were fabricated by the injection of (i) the as-received alumina particles and (ii) milled mixture of alumina with Al and Mg powders [composite powder (CP)] into semi-solid Al alloy. The influences of interfacial characteristics as well as microstructural evolution on wear properties were then explored. Microstructures of the composite, worn surfaces, and worn surface side views were characterized by field emission scanning electron microscopy and transmission electron microscopy, and interfacial failure loads were evaluated by high load nano-indentation test. Obtained results revealed augmented wear resistance in the composites fabricated via CP injection into the semi-solid alloy. Improvement in wear resistance was ascribed to lower thickness and higher bonding strength of alumina/matrix interface as well as uniform distribution of grains as a consequence of recrystallization beneath the worn surface.

Tungsten trioxide nanopetal with Fe2O3 composite films were synthesized by dealloying the W-Fe alloy film in HCl aqueous solution; nano-Pd particles were directly electrochemical deposited on the surface of dealloying films in a micro-emulsion system and following thermal oxidation in air. The structure, morphology, chemical composition and quality of the prepared WO3 nanopetal with Fe2O3 composite films were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The results showed that the thickness of the WO3 nanopetals were less than 50 nm, which were monoclinic phase after controlled thermal oxidation process, and the nano-Pd particles were evenly dispersed on the WO3 film surface with controlled diameters ranging from 20 to 40 nm. The sensors were tested for 25-2000 ppm H2 at temperatures from 50 to 200 degrees C; and the H2 sensing properties of Pd loading (1.54 at.%) WO3-Fe2O3 composited films exibited the best response at the low working temperature of 125 degrees C.

We report synthesis of the sodium cobalt oxide γ-NaxCoO2 submicron tubules using the citric acid-based sol-gel route with the assistance of commercial porous anodized aluminium oxide (AAO) membrane with a nominal pore size of 200nm as supporting templates. The γ-NaxCoO2 submicron tubules can be obtained at 500°C using a rapid-heat-up procedure and held for 30 min. The submicron tubules have a diameter of 200-250 nm. The products are investigated using various techniques including powder x-ray diffraction, field emission scanning electron microscope and transmission electron microscope. The atomic ratio of Na/Co of theγ-NaxCoO2 submicron tubules is determined using energy dispersive x-ray spectra. The atomic ratio of Na/Co tends to be less than 0.5 due to the tendency of Na+ de-intercalating from its parent structure during the tubules collecting process.