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Cd-doping and nanofibrous morphology are proposed to improve the TiO2 performance as photoanode in the dye-sensitized solar cells. Practical results indicate that Cd ions interfered with the crystalline structure of TiO2 nanofibers, causing an increase in the absorption in the visible spectrum, transport of the charges, and reduced re-bonding between the charge carriers in the barrier area between the electrolyte and the working electrode, compared to the un-doped titania nanofibers. It is interesting that a DSSC based on a Cd-doped TiO2 nanofiber working electrode has a double power conversion efficiency (2.945%) compared with the pristine titanium oxide nanofibers-based cell; 1.54%.

SnO2-decorated graphene oxide (SnO2/GO) was synthesized by the modified Hummers&rsquo, s method, followed by a chemical incorporation of SnO2 nanoparticles. Then, the nanocomposite was used as anon-precious counter electrode in a dye-sensitized solar cell (DSSC). Although GO has a relatively poor electrical conductivity depending essentially on the extent of the graphite oxidation, presence of SnO2 enhanced its structural and electrochemical properties. The Pt-free counter electrode exhibited a distinct catalytic activity toward iodine reduction and a low resistance to electron transfer. Moreover, the decorated GO provided extra active sites for reducing I3&minus, at the interface of the CE/electrolyte. In addition, the similarity of the dopant in the GO film and the fluorine-doped tin oxide (FTO) substrate promoted a strong assimilation between them. Therefore, SnO2-decorated GO, as a counter electrode, revealed an enhanced photon to electron conversion efficiency of 4.57%. Consequently, the prepared SnO2/GO can be sorted as an auspicious counter electrode for DSSCs.

Among the various carbonaceous materials, graphene is highly considered to provide the optimum support for the electrocatalytic materials due to its excellent electrical conductivity and extremely large surface area. In literature, based on our best knowledge, few studies have been reported to introduce effective electrocatalysts for urea oxidation. In this study, Ni-decorated graphene sheets are introduced as effective and stable electrocatalyst for urea oxidation. The introduced composite was prepared by reflux of graphene oxide with nickel acetate at 120 °C for 10 h followed by calcination in argon atmosphere at 850 °C for 2 h. X-ray diffractometer (XRD), transmission electron microscope (TEM) and Raman spectroscopy techniques confirmed formation of graphene sheets decorated by nickel nanoparticles. The synthesized Ni-decorate graphene shows distinct electrocatalytic activity toward urea oxidation. Numerically, using 2 M urea solution (in 1 M KOH) the corresponding current density was 150 mAcm −2 (2100 mAcm −2 g −1 ) with clear urea oxidation peaks in the forward and reverse scans. Study the influence of metal loading indicated that the amount of nickel nanoparticles should be optimized as the best performance has been observed when equal amounts of nickel acetate and graphene oxides were utilized during the preparation process. The introduced decorated graphene reveals good stability at various applied voltages. Overall, the study emphasizes the advantage of using graphene as support to distinctly enhancing urea electrooxidation.

The study introduces novel Co/Cr-decorated carbon nanofibers to be used as an effective counter electrode in the dye-sensitized solar cells. The decorated carbon nanofibers were prepared by a simple technique; electrospinning. Typically, calcination of electrospun nanofibers composed of cobalt acetate, chromium acetate and poly vinyl alcohol in argon atmosphere results in producing carbon nanofibers decorated by CoCr nanoparticles. The crystallinity, purity and morphology of the introduced nanofibers were inspected by scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), TEM mapping and line TEM EDX. These characterization techniques affirmed the formation of good morphology carbon nanofibers decorated by Co/Cr nanoparticles. Cyclic voltammetry technique indicated that the modified carbon nanofibers have a high performance to reduce iodine to iodide ions with strong dependence of the redox peaks intensities on the scan rate which indicates high reversibility and simultaneously supports exploiting these nanofibers as a counter electrode in the dye sensitized solar cells (DSSCs). Accordingly, the DSSC based on utilizing the introduced nanofibers as counter electrode exhibits good performance; photovoltaic conversion efficiency of 3.27%, open circuit voltage of 0.685 V and a short-circuit current density of 8.784 mA/cm2. Moreover, electrochemical impedance spectroscopy (EIS) analysis revealed low electrical resistance of the counter electrode. From these results, the synthesized Co/Cr-decorated carbon nanofibers can be considered as a promising Pt-free counter electrode for dye sensitized solar cells.

Recently, treatment of water contaminated by petroleum fractions is a hot issue due to presence of large amounts of such waste waters. Membrane technology is the most convenient process can be exploited. In this article, polysulfone (PSF), as a widely used polymer in membranes manufacturing, was utilized to synthesize novel and effective electrospun nanofiber membranes for petroleum fractions/water separation process. The separation efficacy was enhanced by doping the PSF electrospun nanofibers by amorphous silica nanoparticles (extracted from rice husk by subcritical water technique) and graphene oxide (GO) individually. Although, addition of nano-silica and GO led to slight increase and decrease in the contact angle, respectively and all the prepared membranes (pristine, SiO2-doped, and GO-doped PSF) could be utilized successfully in the separation process, SiO2 NPs addition strongly enhanced the flux. Typically, the prepared membranes successfully separated kerosene/water, gasoline/water and hexane/water solutions into their constituents. However, in case of hexane/water, the corresponding daily flux was 23, 38 and 187 m3/m2 for pristine, GO-doped and SiO2-doped PSF nanofiber membranes, respectively. Besides enhancing the daily flux, mechanical strength tests showed that Young’s modules was enhanced by the addition of SiO2 NPs while GO has a negative influence on the mechanical properties. UV–visible spectroscopic analysis proved complete separation for the utilized mixtures. Overall, it can be claimed that the nanosilica obtained from rice husk agriculture waste can be utilized to prepare effective PSF-based electrospun nanofiber membrane for petroleum oil fractions/water with daily flux of 100, 115 and 187 m3/m2 for, gasoline, kerosene and hexane, respectively.

In this work, Co/Cr nanoparticles-decorated carbon nanofibers were studied as a platinum-free catalyst for electrooxidation of ethanol in the alkaline medium. The investigated nano composites were prepared by simple, high yield and effective technique; electrospinning of cobalt acetate, chromium acetate and polyvinyl alcohol as a polymer precursor at 20 kV followed by calcination under inert atmosphere at 900 °C for 2 h. The suitable physicochemical characterizations such as XRD, SEM, TEM, TEM mapping, Line TEM-EDX and FE-SEM indicated the formation of pure CoCr nanoparticles allocated in/on carbon nanofibers. Electro catalytic activity measurements showed that the investigated Co–Cr carbon nanofibers can be effectively utilized in ethanol electrooxidation in 1 mol/l KOH solution. The observed current density was 105 mA/cm2 which is considered high value for non-precious electrocatalyst. Also, study the influence of Cr content in Cr–Co alloy toward ethanol oxidation was investigated to obtain the most effective composition. The suitable Cr concentration found to be 10% of Co content.

NiCu bimetallic nanoparticle-decorated graphene was prepared by hydrothermal treatment to be utilized as an efficient and alternative Pt-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). The results indicated that the performance of the introduced modified graphene as CE strongly depends on the composition of the metallic nanoparticles. Typically, Ni-, Ni 0.25 Cu 0.75 -, Ni 0.6 Cu 0.4 - and Ni 0.75 Cu 0.25 -decorated graphene were synthesized. Investigation of the electrochemical characteristics indicated that the graphene decorated by Ni 0.75 Cu 0.25 nanoparticles shows the highest catalytic activity and conductivity compared to the other prepared formulations as well as pristine graphene. In DSSC, Ni 0.75 Cu 0.25 nanoparticle-decorated graphene can remarkably improve the catalytic activity toward triiodide reduction and lower the resistance at the electrolyte–CE interface. Accordingly, the obtained energy conversion efficiencies were 1.72%, 2.39%, 1.24%, 2.87% and 5.1% for pristine, Ni-, Ni 0.25 Cu 0.75 -, Ni 0.6 Cu 0.4 - and Ni 0.75 Cu 0.25 -decorated graphene, respectively. The obtained efficiency for Ni 0.75 Cu 0.25 -decorated graphene is comparable with Pt-based DSSC fabricated by the same procedure (5.9%) which recommends exploiting the introduced modified graphene as efficient and cost-effective CE for the large-scale fabrication of photovoltaic devices. The catalytic performance of the best formulation was examined toward methanol electrooxidation; the results indicated effective and stable electrocatalytic activity.

For DSSCs application, highly efficient photoelectrode based on nitrogen (N) and graphene oxide (GO) co-incorporated TiO2 nanofibers were synthesized successfully by two simple successive methods; electrospinning followed by hydrothermal processes. The influence of the N and GO co-incorporation on the morphology, crystal structure and optical behavior of TiO2 nanofibers were characterized by various advanced techniques. The results showed that the modified TiO2 nanofibers exhibit higher conversion energy in comparison to the mono-incorporated and pristine TiO2 nanofibers. Optical and electrochemical properties study indicated that, compared to other GO contents, the 0.5 wt% GO content provides higher surface area, more active sites for the dye absorption, and numerous hot electron transport paths to the FTO substrate which consequently improves the cell performance. On the other hand, N atoms incorporation causes positive shift of the flat band potentials (Vfb) which leads to fast electron transport in TiO2 nanofiber films and inhibits the charge recombination rate of photon-generated electrons. Accordingly, TiO2 nanofibers co-incorporated by nitrogen and GO (0.5 wt%) exhibit the best performance as photoanode in the DSSC, the corresponding conversion efficiency was 5.72% compared to 4.52% and 1.54% in case of nitrogen-free 0.5 wt% GO-incorporated and pristine TiO2 nanofibers, respectively. Overall, this study introduces nitrogen and graphene oxide co-incorporation in the titanium oxide nanofibers as novel strategy for enhancing the solar-to-electrical energy conversion in the DSSCs.

NiCo nanoparticles(NPs)-doped carbon nanofibers were synthesized by calcination of electrospun nanofibers composed of nickel acetate, cobalt acetate and poly(vinyl alcohol) in argon atmosphere and used as an efficient and alternative Pt-free electrocatalyst as counter electrode materials for dye-sensitized solar cells (DSSCs). Structural and electrochemical properties of the NiCo NPs-doped carbon nanofibers counter-electrodes were inspected by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), andelectrochemical impedance spectroscopy (EIS). This Pt-free counter electrode shows high catalytic activity, surface area and conductivity. Moreover, more catalytic active sites for the reduction reaction at the electrolyte/counter electrode interface and strong contact between the film and FTO substrate have been observed. Therefore, the DSSCs based on NiCo (NPs) carbon nanofibers counter exhibits an enhanced photovoltaic conversion efficiency of 4.47%. As the result, the introduced nanofibers can be considered as a promising counter electrode for DSSCs.

In this study, the photocatalytic activity of TiO2 nanofibers toward ammonia borane hydrolysis has been strongly modified by doping the nanostructure by ZnO and Fe2O3 oxides. Due to the differences in the work function and band gap energy among the three semiconductors (TiO2, ZnO and Fe2O3), illumination of TiO2 leads to accumulate the electrons and holes on the conduction and valance bands of Fe2O3 and ZnO, respectively. Accordingly, the experimental results indicated that the surface of the obtained nanofibers is very active which results in an instant hydrolysis of ammonia borane molecules reaching the active zone surrounding the nanofibers. Moreover, negative activation energy was determined as increasing the temperature led to decrease the photocatalytic performance. Furthermore, kinetic studies indicated that the heterogeneous catalytic reaction describing the ammonia borane hydrolysis process is zero order which additionally supports the super activity of the introduced nanofibers. It was a...

Capacitive deionization (CDI) is a second generation electrosorption technique for removing the salt ions from the brackish water. Among the carbonaceous materials, graphene can be considered to be a promising CDI electrode material due to its exceptional physical properties and chemical tenability. In this study, graphene/tin dioxide nanoparticles composites (Gr/SnO 2 ) with different proportions were successfully synthesized via microwave irradiation; their electrosorption performances in CDI unit were investigated. The morphology, crystal structure and electrochemical performance were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry. The obtained results indicated that incorporation of SnO 2 into graphene has a great impact for enhancing the electrosorption capacity. Compared to pristine graphene electrode, higher specific capacitance was observed for all the fabricated Gr/SnO 2 composite electrodes. Specifically, the electrode having 15 wt% SnO 2 exhibits distinguished electrochemical performances: high specific capacitance (323 F/g), excellent cycling stability, very good salt removal efficiency (83%), and distinct electrosorptive capacity of 1.49 mg/g. Overall, the present study demonstrates an effective and facile route to distinctly improve the desalination performance of graphene-based electrodes for CDI technology.

Bimetallic alloys have superior physiochemical characteristics compared to the individual metals. In this study, Ni x Co 1− x ( x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) alloy nanoparticles incorporated in carbon nanofibers are investigated as electrocatalysts for methanol oxidation in the alkaline media. Preparation of the introduced nanofibers is achieved by calcination of electrospun nanofibers composed of nickel acetate, cobalt acetate and poly(vinyl alcohol) in argon atmosphere. The catalytic activity of cobalt enhances the carbonization of the utilized polymer which results in producing nickel/cobalt alloys nanoparticles embedded in carbon nanofibers. Due to the synergistic influence of the introduced alloy, both of the current density and onset potential were distinctly affected by the nanoparticles composition; Ni 0.5 Co 0.5 alloy nanoparticles-doped carbon nanofibers reveal current density and onset potential of 240 mA/cm 2 and 110 mV [vs. Ag/AgCl], respectively. Interestingly it was proofed that, compared to nanoparticles, the nanofibrous morphology has a distinct positive influence on the electrocatalytic activity due to the effect of the one dimensional structure which facilitates the electrons transfer and consequently decreases the IR drop. The introduced nanofibers showed good stability because of the alloy structure. Overall, this study opens new avenue for the transition metals alloys and the nanofibrous morphology to be invoked to produce novel and effective class of non-precious electrocatalysts.

The band gap energy, defects, recombination centers and photocorrosion resistance are the main features of the good photocatalyst to be exploited in the water splitting process under visible light radiation. Moreover, the nanomorphology has considerable impact. In this study, the band gap energy of titanium oxide nanofibers was modified by Fe 2 O 3 - and ZnO-incorporation to be used as effective photocatalysts in water splitting process under visible light radiation. The experimental results indicated that the band gap energy can be reduced to 1.89 eV when TiO 2 nanofibers are incorporated by 5 wt% ZnO and 5 wt% Fe 2 O 3 . However, the optimum performance in the water splitting process was observed with the nanofibers containing 5 wt% ZnO and 6 wt% Fe 2 O 3 (the corresponding band gap energy was 2.25 eV); the observed hydrogen production rate was 0.12 ml/min mg cat which is considered unprecedented value. The introduced super effective nanofibers were prepared using the electrospinning process. Typically, electrospun nanofibers composed of titanium(IV) isopropoxide, iron(II) acetate, polyvinylpyrrolidone and zinc acetate dihydrate were calcined in air at 700 °C. With respect to TiO 2 content, the composition of the electrospun solutions were adjusted to produce nanofibers containing ZnO and Fe 2 O 3 contents of 5, 10 and 15 wt%, and 3, 6 and 10 wt%, respectively. The produced nanofibers were characterized by SEM, FE-SEM, TEM, TEM-EDX, and XRD analyzing techniques. Due to the polycondesation characteristic of the utilized metallic precursors, the nanofibrous morphology was not affected by the calcination process.

Graphene and alloy structure can overcome the main problem facing the non-precious electro-catalysts; low performance and poor stability. In this study, Co x Ni y -decorated graphene is introduced as novel, super effective and stable non-precious electro-catalyst for methanol oxidation. The obtained results have indicated that utilizing graphene as a support strongly enhances the electro-catalytic activity as the current density was doubled ten times, moreover a negative onset potential (−40 mV vs. Ag/AgCl) was obtained which is a distinct progress in the non-precious electro-catalysts research field. The electronic structure which is controlled by the alloy composition showed strong influence on the electro-catalytic activity; Co 0.2 Ni 0.2 alloy nanoparticles revealed the best performance while Co 0.1 Ni 0.3 nanoparticles were the worst. Due to the alloy structure, the introduced graphene-supported electro-catalyst reveals distinguished stability. In-situ decoration of graphene by Co x Ni y alloy nanoparticle is utilized to produce the introduced electro-catalyst. Briefly, cobalt acetate and nickel acetate were added to the reaction media during graphene preparation using a modified chemical route. Later on, the resultant material was calcined in argon atmosphere at 850 °C. The utilized physicochemical characteristics affirmed formation of multi-layer graphene sheets decorated by solid solution Co x Ni y alloy nanoparticle.

By scanning tunneling microscopy and synchrotron photoemission spectroscopy, it has been found that through CaF 2 exposure to the single-domain Si(001)-4° off surface held at 750 °C, Si dimers on Si(001) terraces are replaced preferentially by dissociated Ca atoms while F atoms are desorbed. The resulting 2 × 3 reconstruction saturates the (001) terraces at a coverage between 0.1 and 0.3 monolayers. Additional CaF 2 exposure triggers a structural transformation to a stable hill-and-valley structure composed of wider (001)-2 × 3 terraces and compensating facets comprised of (11 17) and (11 13) units, both with a 6 × 1 surface reconstruction. This study demonstrates that the periodic width of the single domain Si(001) surface can be modulated through adsorbing Ca atoms while maintaining one-dimensional symmetry along the D B steps and the semiconducting nature of the surface.

Highly efficient dye-sensitized solar cell (DSSC) was fabricated using nitrogen-doped TiO 2 nanofibers successfully prepared by the electrospinning process followed by hydrothermal treatment. The influence of the nitrogen doping on the morphology, crystallinity and optical behaviour of TiO 2 nanofibers were analysed by field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD), X-ray photoemission spectroscopy (XPS), electrochemistry impedance spectra (EIS) and UV- vis spectroscopy analyses. Experimental results evidenced the incorporation of nitrogen atoms into the lattice of TiO 2 nanofibers which led to enhancement of the absorption in the visible light region, the charge transfer, electron lifetime and the recombination reaction at the TiO 2 photoelectrode/electrolyte interface as compared to the pristine TiO 2 nanofibers. It was found that the overall conversion efficiency of DSSCs based on photoanode of N-doped TiO 2 nanofiber is significantly higher than DSSCs based on un-doped TiO 2 nanofibers. Typically, doping TiO 2 nanofibers by nitrogen atoms led to increase the current density from 6.75 to 11.16 mA/cm 2 . Moreover, the N-doped TiO 2 nanofibers revealed energy conversion efficiency of 4.7% which is distinctly high compared to the un-doped nanofibers which showed 1.56%.

Alloy structure generates special characteristics for the nano-metallic compounds which make this interesting class of materials promising candidates for many application fields. Moreover, the performance of the nanostructural catalysts is strongly influenced by the morphology; nanofibers reveal distinct catalytic activity compared to the nanoparticles. In this study, non-precious electrocatalysts based on alloy structure and nanofibrous morphology are introduced. Briefly, Ni x Co 1− x ( x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) alloy nanoparticles incorporated in carbon nanofibers are investigated as electrocatalysts for ethanol oxidation. Preparation of the introduced nanofibers could be achieved by calcination of electrospun nanofibers composed of nickel acetate tetrahydrate, cobalt acetate tetrahydrate and poly(vinyl alcohol) in argon atmosphere at 800 °C. Polycondensation characteristic of the utilized metals precursors led to produce good morphology electrospun nanofibers as well as preserved the nanofibrous morphology during the calcination process for all formulations. The catalytic activity of cobalt enhanced the carbonization of the utilized polymer which resulted in producing nickel/cobalt alloys nanoparticles embedded in carbon nanofibers. Electrochemical investigation of the introduced nanofibers toward ethanol oxidation indicated that the alloy structure has a strong influence. For instance, the corresponding current densities of Ni- and Ni 0.9 Co 0.1 -doped carbon nanofibers were 37 and 142 mA/cm 2 , respectively. Moreover, very low onset potential (−50 mV vs. Ag/AgCl) was observed when Ni 0.1 Co 0.9 -doped carbon nanofibers were utilized. Furthermore, Ni 0.9 Co 0.1 -doped carbon nanofibers could oxidize ethanol solution up to 5 M due to the observed active layer regeneration. The introduced nanofibers have good stability because of the alloy structure. Overall, this study opens new avenue for the transition metals alloys and the nanofibrous morphology to produce novel and effective non-precious electrocatalysts.

Well decorated Co/TiO2 nanoparticles incorporated carbon nanofibers are presented as operative electrocatalyst in term of current density and onset potential for methanol oxidation. The presented electrocatalyst has been prepared by well-known technique; electrospinning. The physicochemical properties have been confirmed by FE-SEM, EDX, SEAD and TEM analyses while the electrocatalytic studies has been performed by cyclic voltammetry technique. Obtained results indicate that TiO2 content has strong influence for direct fuel cell. Co (99%)/TiO2 (1%) incorporated carbon nanofibers showed best performance in term of high current density at low onset potential. Overall, the introduced Co (99%)/TiO2 (1%) incorporated carbon nanofibers as an electrocatalyst can be considered a promise material for direct methanol fuel cells applications.

This work aims to investigate the tensile and compression strengths of heat- cured acrylic resin denture base material by adding styrene-butadiene (S- B) to polymethyl methacrylate (PMMA). The most well- known issue in prosthodontic practice is fracture of a denture base. All samples were a blend of (90%, 80%) PMMA and (10%, 20%) S- B powder melted in Oxolane (Tetra hydro furan). These samples were chopped down into specimens of dimensions 100x10x2.5mm to carry out the requirements of tensile tests. The compression strength test specimens were shaped into a cylinder with dimensions of 12.7mm in diameter and 20mm in length. The experimental results show a significant increase in both tensile and compression strengths when compared to control (standard) results for the preparation material.

Recently, the bimetallic nanostructures reveal good photoelectrochemical catalytic activity. Low chemical resistance is the main constraint preventing wide applications for this new interesting class of nanocatalytic materials. In this study, the active CuNi bimetallic nanoparticles have been incorporated inside carbon nanofibers. Interestingly, the graphite sheath did not affect the catalytic activity of the CuNi NPs as the introduced nanofibers revealed distinct performance as a counter electrode for the dye-sensitized solar cell (DSSC). The synthesized nanofibers based DSSC shows a conversion efficiency of 3.5%, open-circuit voltage of 0.70 V and a short-circuit current density 7.67 mA/cm 2 . New bimetallic incorporated nanofibers have been prepared by low cost facile electrospinning technique followed by the calcination of electrospun nanofiber mats consisting of nickel acetate, copper acetate, and poly (vinyl alcohol) in argon atmosphere which led to the partial decomposition of the utilized polymer and abnormal decomposition of the metallic acetate to achieve CuNi NPs enveloped in carbon nanofibers Finally, it is worthy mentioned that the development of new materials as catalyst and electrocatalyst in the field of energy would be considered a key objective of modern research.

The atomic structure and interfacial bonding of the ordered-and-isolated CaF nanowires on Si(5 5 12)-2 × 1 have been disclosed by scanning tunneling microscopy and synchrotron photoemission spectroscopy. Initially, CaF molecules dissociated from thermally deposited CaF2 molecules are adsorbed preferentially on the chain structures of Si(5 5 12)-2 × 1 held at 500 °C. With increasing CaF2 deposition amount, one-dimensional (1D) CaF nanowires composed of (113) and (111) facets are formed. The line density of these CaF nanowires increases as a function of deposition amount. Finally, at a submonolayer coverage, the surface is saturated with these 1D nanowires except for the (225) subunit, while the original period of Si(5 5 12)-2 × 1, 5.35 nm, is preserved. It has been deduced by the present studies that, owing to these preferential adsorption of CaF and facet-dependent growth of a CaF layer within a unit periodic length of Si(5 5 12)-2 × 1, such a self-limited growth of the CaF nanowire with a high aspect ratio becomes possible.

Cobalt-Chrome nanoparticles-incorporated carbon nanofibers (CNFs) are proposed as an effective nonprecious electrocatalyst for methanol oxidation in the alkaline media. The introduced nanofibers were prepared by simple technique, electrospinning. Carbonization of as-spun mat composed of chromium acetate, cobalt acetate and poly(vinyl alcohol) (PVA) at high temperature (900[Formula: see text]C) leads to production of the introduced nanofibers. The physicochemical characteristics were investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) equipped with EDX and TEM mapping. The exploited analyses confirmed that the final product is in the form of CNFs decorated by Co/Cr nanoparticles. Based on the results obtained from the cyclic voltammetry (CV) measurements, the proposed Co/Cr-incorporated CNFs possess high electrocatalytic activity toward methanol electrooxidation as a clear peak of methanol oxidation appeared with corresponding current density of 56[Formula: see text]mA/cm2. Moreover, the current density increased by increasing methanol concentration up to 4.0[Formula: see text]M. Overall, the proposed nanofibers open new avenue for platinum-free and stable nanostructural catalysts for fuel cell technology.

By combined investigation of scanning tunneling microscopy and synchrotron core-level photoemission spectroscopy on the structural and chemical evolution at the initial stage of Ge adsorption on Si(114)-2 × 1, it has been observed that one-dimensional (1D) sawtooth-like nanostructures composed of (113) and (117) facets and 1D trenches adjacent to the (113) facets are readily formed without any wetting layer. Due to the absence of chain structures on the reconstructed Si(114)-2 × 1, enhanced Ge interdiffusion detected from Ge/Si(5 5 12)-2 × 1 has not been found. Instead, Si atoms originating from etched surfaces and arriving Ge atoms form the alloy facets with Ge-rich surfaces. These experimental results prove that, if the direction of the Ge overlayer corresponding to that of the substrate is unstable like the present case, the arriving atoms prefer to form facets covered with the species of lower surface free energies rather than a uniform wetting layer.