Atefeh Ghaderi

Bio: Atefeh Ghaderi is an academic researcher from Islamic Azad University. The author has contributed to research in topics: Thin film & Materials science. The author has an hindex of 21, co-authored 34 publications receiving 971 citations. Previous affiliations of Atefeh Ghaderi include Razi University.

Microstructure and Tribological Properties of FeNPs@a-C:H Films by Micromorphology Analysis and Fractal Geometry

Abstract: This paper analyzes the three-dimensional (3D) surface texture of amorphous hydrogenated carbon films with sputtered iron nanoparticles (FeNPs@a-C:H) deposited by a radio-frequency plasma-enhanced chemical vapor deposition method on the quartz substrates. The prepared FeNPs@a-C:H films were used as research materials. The synthesized samples were deposited at four different pressures of 2.5, 3, 3.35, and 3.5 N/m2 in an acetylene gas atmosphere. The Fe and C contents of the thin films were obtained from X-ray photoelectron spectroscopy. The X-ray diffraction profile and electron diffraction pattern indicate that iron nanoparticles with body-centered-cubic crystalline structure are formed in these films. The localized surface plasmon resonance peak that is the signature of the existence of the iron core nanoparticles appears in visible spectra of these films. The sample surface images were recorded using an atomic force microscope operating in a noncontact mode and analyzed to reveal the statistical, fracta...

Stereometric Parameters of the Cu/Fe NPs Thin Films

Abstract: This paper analyses the three-dimensional (3-D) surface morphology of thin films of Fe on Cu nanoparticles (NPs) synthesized by direct-current (DC) magnetron sputtering deposited on glass substrates. Four samples coated with copper and iron and deposited on the glass surface were used as research materials. Thin films were obtained by means of a DC reactive magnetron sputtering method. The copper coating of each sample was 55 nm thick. In addition, the second, third, and fourth samples had a coating of iron, with a thickness of 40, 55, and 70 nm, respectively. The sample surface images were obtained by using an atomic force microscope operating in a contactless mode. The 3-D of the surface samples was divided into motifs of significant peaks and pits using MountainsMap Premium software, which uses the watershed segmentation algorithm. In addition, the highest and lowest points of motifs are localized. The parameters relating to all the segmented motifs consistent with ISO 25178-2:2012 have been generated ...

Microstructure, morphology and electrochemical properties of Co nanoflake water oxidation electrocatalyst at micro- and nanoscale

Abstract: Nowadays, fossil fuel limitations and environmental concerns push researchers to find clean and renewable energy resources. Solar hydrogen production via water splitting reactions in electrochemical and/or photo-electrochemical systems has been accepted as a promising route and efficient electrocatalysts are involved in both. Here, cobalt nanoflakes with an oxide/hydroxide surface and a conductive metallic core are grown on commercially available steel mesh modified with carbon based nanocomposites as a support layer. The portion of reduced graphene oxide sheets was changed from 0 to 100 wt% and the correlation of this concentration with the surface morphology and electro-catalytic activity of the final electrode was studied systematically for the first time. Obtained results revealed the least over potential (224.2 mV) for the sample with 50 wt% rGO in the water splitting reaction which is promising for use in alkaline electrolysis devices.

Fractal features and surface micromorphology of diamond nanocrystals

Abstract: This paper analyses the three-dimensional (3-D) surface texture of growing diamond nanocrystals on Au thin films as catalyst on p-type Si substrate using hot filament chemical vapour deposition (HFCVD). Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM), Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were applied also to characterize the 3-D surface texture data in connection with the statistical, and fractal analyses. This type of 3-D morphology allows a deeper understanding of structure/property relationships and surface defects in prepared samples. Our results indicate a promising way for preparing high-quality diamond nanocrystals on Au thin films as catalyst on p-type Si substrate via HFCVD method.

Effect of preparation methods on the properties of titania nanoparticles: solvothermal versus sol–gel

Abstract: Titania (TiO2) nanoparticles (NP’s) have been prepared by solvothermal and sol–gel techniques using different surfactants such as acetic acid (AA), oleylamine (OM), and AA + OM. The solution was thermally treated at growth temperature 180 °C in solvothermal method. TiO2 powder, prepared using both methods, was subjected to post heat treatment at 550 and 950 °C. The effect of surfactants on the morphology of TiO2 NP’s was studied by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The structural and thermal properties of titania NP’s are investigated by means of X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and differential scanning calorimetry (TGA/DSC). TEM and FESEM images illustrated various shapes of titania NP’s such as irregular spherical, rounded rectangular, truncated rhombic, oval, and rod-like structure in presence of different surfactants. Moreover, TiO2 particles prepared by sol–gel method were almost 40 times greater than those prepared by solvothermal method. In addition to the improvement in the crystallinity, thermal stability has been enhanced due to consolidation of individual particles at higher annealing temperature in solvothermal technique. Furthermore, a reduction in the degradation temperature and phase transformation of TiO2 NP’s were conspicuously corroborated after post-heat treatment.

Nickel selenide supported on nickel foam as an efficient and durable non-precious electrocatalyst for the alkaline water electrolysis

Abstract: Herein, we describe an in-situ hybridization of Nickel Selenide (Ni3Se2) with a Nickel Foam (NF) current collector as an efficient, ultra-durable electrode for the continuous alkaline water electrolysis. Earth abundant, cost effective, non-precious self-made Ni3Se2/NF electrode delivers an oxygen evolution reaction (OER) overpotential value of 315 mV at a current density of 100 mA cm−2 (versus a reversible hydrogen electrode) in aqueous electrolyte of 1 M KOH. On a static current density of 100 mA cm−2, Ni3Se2/NF electrode shows a good OER stability over 285 h with very small potential loss of 5.5% in alkaline electrolyte. Accordingly, the alkaline water electrolyzer constructed with Ni3Se2/NF (anode) and NiCo2S4/NF (cathode), it requires 1.58 V to deliver 10 mA cm−2 current density, with 500 h continuous operation in 1 M KOH. In addition, we demonstrate that the light-driven water splitting using solar panel, it can be a promising approach to facilitate true independence from electricity in H2 fuel economy. Overall, this methodology is one of the appropriate energy efficient ways to reduce the cost of water splitting devices, as it may simplify the diverse process and equipment.

Enhanced Gas Sensing Properties of Spin-coated Na-doped ZnO Nanostructured Films.

Abstract: In this report, the structures, morphologies, optical, electrical and gas sensing properties of ZnO and ZnO: Na spin-coated films are studied. X-ray diffraction (XRD) results reveal that the films are of a single phase wurtzite ZnO with a preferential orientation along (002) direction parallel to c-axis. Na doping reduces the crystalline quality of the films. The plane surface of ZnO film turned to be wrinkle net-work structure after doping. The reflectance and the optical band gap of the ZnO film decreased after Na doping. The wrinkle net-work nanostructured Na-doped film shows an unusually sensitivity, 81.9% @ 50 sccm, for CO2 gas at room temperature compared to 1.0% for the pure ZnO film. The signals to noise ratio (SNR) and detection limit of Na-doped ZnO sensor are 0.24 and 0.42 sccm, respectively. These enhanced sensing properties are ascribed to high surface-to-volume ratio, hoping effect, and the increase of O- vacancies density according to Kroger VinK effect. The response time increased from 179 to 240 s by the incorporation of Na atoms @50 sccm. This response time increased as the CO2 concentration increased. The recovery time is increased from 122 to 472 s by the incorporation of Na atoms @50 sccm.