Fast synthesis of multilayer carbon nanotubes from camphor oil as an energy storage material

Among the wide range of renewable energy sources, the ever-increasing demand for electricity storage represents an emerging challenge. Utilizing carbon nanotubes (CNTs) for energy storage is closely being scrutinized due to the promising performance on top of their extraordinary features. In this work, well-aligned multilayer carbon nanotubes were successfully synthesized on a porous silicon (PSi) substrate in a fast process using renewable natural essential oil via chemical vapor deposition (CVD). Considering the influx of vaporized multilayer vertical carbon nanotubes (MVCNTs) to the PSi, the diameter distribution increased as the flow rate decreased in the reactor. Raman spectroscopy results indicated that the crystalline quality of the carbon nanotubes structure exhibits no major variation despite changes in the flow rate. Fourier transform infrared (FT-IR) spectra confirmed the hexagonal structure of the carbon nanotubes because of the presence of a peak corresponding to the carbon double bond. Field emission scanning electron microscopy (FESEM) images showed multilayer nanotubes, each with different diameters with long and straight multiwall tubes. Moreover, the temperature programmed desorption (TPD) method has been used to analyze the hydrogen storage properties of MVCNTs, which indicates that hydrogen adsorption sites exist on the synthesized multilayer CNTs

The frequency of Staphylococcus aureus among Shiraz hospital personnel and determination of their antibiotic sensitivity pattern

Background: Improper use of antibiotics in the past decades has lead to appearance of strains which are resistant to methicillin and vancomycin . Hospital personnel are the major source of infection and transmission of this bacterium. The aim this study was to determine the antibiotic susceptibility of to S.aureus isolated from personnel of Shiraz hospitals. Material and Methods: In this cross - sectional study in 1391,a total of 591 samples were collected from anterior nose of health care and health service workers of Shiraz hospitals. After identification of Staphylococcus aureus by biochemical and microbiological tests, antibiotic resistance patterns of isolates were investigated by disk diffusion method (CLSI) for 13 antibiotics. Minimum inhibitory concentration (MIC) values for vancomycin ,ticoplanin, linezolid and Quinupristin-Dalfopristin were assayed by E-test method (Liofilechem, Itly). Results: In this study14.6% of people were carriers of Staphylococcus aureus in their nose. 74% were health care workers and 26% were health service personnel. There was not statistically significant relation between being a nasal carrier with different jobs, wards or sex of personnel (p>0.05). The lowest resistance was seen for vancomycin, tiecoplanin, linezolid and Quinupristin-Dalfopristin (95.3%) and the high resistant antibiotic were amoxicillin and ampicillin (3.5%). In E-test method only two isolate was resistant to vancomycin. Only two strains were resistant to vancomycin in E-test method. Conclusion: As 14.6% of personnel in this study were carriers of Staphylococcus aureus and the isolates were resistant to most common antibiotics, thus determination of antibiotic resistance patterns for these resistant strains from hospital personnel can prevent nosocomial infections

High-performance dye-sensitized solar cells based on morphology-controllable synthesis of ZnO-ZnS heterostructure nanocone photoanodes.

High-density and well-aligned ZnO-ZnS core-shell nanocone arrays were synthesized on fluorine-doped tin oxide glass substrate using a facile and cost-effective two-step approach. In this synthetic process, the ZnO nanocones act as the template and provide Zn2+ ions for the ZnS shell formation. The photoluminescence spectrum indicates remarkably enhanced luminescence intensity and a small redshift in the UV region, which can be associated with the strain caused by the lattice mismatch between ZnO and ZnS. The obtained diffuse reflectance spectra show that the nanocone-based heterostructure reduces the light reflection in a broad spectral range and is much more effective than the bare ZnO nanocone and nanorod structures. Dye-sensitized solar cells based on the heterostructure ZnO-ZnS nanocones are assembled, and high conversion efficiency (η) of approximately 4.07% is obtained. The η improvement can be attributed primarily to the morphology effect of ZnO nanocones on light-trapping and effectively passivating the interface surface recombination sites of ZnO nanocones by coating with a ZnS shell layer

A novel detection method for organophosphorus insecticide fenamiphos: Molecularly imprinted electrochemical sensor based on core-shell Co3O4@MOF-74 nanocomposite

Organophosphorus insecticide fenamiphos (FEN) is utilized to control the detrimental nematode pests. In this report, a novel molecular imprinted electrochemical sensor for insecticide FEN detection was prepared. The molecular imprinted sensor was prepared based on Co3O4 nanowire and core-shell Co3O4@MOF-74 nanocomposite. Firstly, hydrothermal method followed by thermal annealing was applied for the preparation of Co3O4 nanowire. Then, solvothermal technique was used in no presence of metal salts to prepare core-shell Co3O4@MOF-74 nanocomposite. In addition, several solvothermal cycles were tried to optimally adjust the reaction efficiency. After the modification of the clean carbon electrode surfaces with Co3O4@MOF-74 nanocomposites, the molecular imprinted electrodes based on Co3O4@MOF-74 nanocomposites were prepared in presence of 100.0 mM pyrrole as monomer and 25.0 mM FEN as analyte molecule between +0.30 V and +1.50 V by cyclic voltammetry (CV). The prepared molecularly imprinted sensor based on Co3O4 nanowire and core-shell Co3O4@MOF-74 nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), x-ray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and CV. The quantification limit (LOQ) and the detection limit (LOD) were obtained as 1.0 × 10−11 M and 3.0 × 10−12 M, respectively, by using the developed sensor. Hence, the developed molecularly imprinting electrochemical sensor having high selectivity, stability and reproducibility was presented in this study for insecticide FEN detection. © 2021 Elsevier Inc

Performances of the DSSCs based on ZnO nanorods, nanocons, and heterostructure ZnO–ZnS nanocones.

<p>Performances of the DSSCs based on ZnO nanorods, nanocons, and heterostructure ZnO–ZnS nanocones.</p

Optical absorption and reflectance spectra of the samples.

<p>(a) Absorption and (b) reflectance spectra of the ZnO nanorods, nanocons, and ZnO–ZnS core–shell nanocones.</p

The band-edge alignments at the heterointerface between ZnO and ZnS semiconductors.

<p>The band-edge alignments at the heterointerface between ZnO and ZnS semiconductors.</p

XRD patterns of the ZnO–ZnS core-shell nanocone arrays on FTO substrate.

<p>XRD patterns of the ZnO–ZnS core-shell nanocone arrays on FTO substrate.</p

The photocurrent density–voltage characteristics of the ZnO nanostructures

<p>(a) Comparison of photocurrent density-voltage plot of the DSSCs based on ZnO nanorods, nanocons, and ZnO–ZnS nanocones (b) schematic diagram of the energy levels of the hetrostructure ZnO/ZnS photoelectrode in a DSSC.</p

Room-temperature PL spectra of the bare ZnO and the shelled ZnO nanocones.

<p>The inset shows the relative PL intensity ratio between the peak intensity of UV and DLE.</p