isa karimzadeh

Herein, we report the structural, morphological, and chemical properties of the electrochemically   grown Co2+-doped magnetite (Co-Fe3O4) nanoparticles onto functionalized graphene oxide layers (Co2+-doped iron oxide@f-GO composite). The deposition process is done at the galvanostatic mode in the two-electrode system by applying the constant current density of 5 mA cm-2. The fabricated Co2+-doped iron oxide@f-GO composite is characterized via Scanning Electron Microscopy, energy dispersive X-ray analysis, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and X-Ray diffraction analysis. TEM observation revealed that Co-Fe3O4 has fine particle morphology with size of 5-10 nm. The FTIR data proved the graphene-based chemical nature of the fabricated composite. The superparamagnetic nature of the prepared composite is proved by vibrating sample magnetometer tests, which verified that the prepared metal-cation doped Fe3O4 nanoparticles grown onto functionalized GO layers could be an interesting candidate for further manipulations for biomedical aims such as drug delivery, magnetic resonance imaging, and hyperthermia.

A high-performance Ni, Co-MOF-G/nickel foam was fabricated using a novel electrodeposition method and used as an electrode material for a supercapacitor application. Structural tests including powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman results affirmed the formation of the electrode active materials. Scanning electron microscopy (SEM) images showed a flower-like Ni, Co-MOF inside graphene sheets forming a composition of active materials on the nickel foam substrate. The electrochemical performance of the Ni, Co-MOF-G/ Nickel foam was examined using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). The prepared electrode delivered approvable specific capacitance of 1158 F g-1 at the current density of 2 A g-1 in three molar potassium hydroxides. Excellent storage capacity of the fabricated electrode is attributed to the synergetic effects of bi-metal metal organic frameworks (Ni, Co-MOF) with porous carbon materials (graphene).

In this paper, well-distributed Lanthanum-doped Superparamagnetic nanoparticles (La-Fe3O4) are reported. Nanoparticles powder has been synthesized using cathodic electrochemical deposition method. By applying a constant current density of 1 A in a two-electrode electrochemical system, nanoparticles with a diameter of approximately 11 nm with a spherical structure were prepared. The structure, morphology and magnetic properties of these nanoparticles have been systematically investigated by using TEM, XRD, VSM and FT-IR analysis. The results indicate the existence of a superparamagnetic behavior at room temperature for progressive measurements as a function of the magnetic field. The magnetic hysteresis (magnetic saturation, Coercivity and Remanence) of the sample shows the effective role of doped lanthanum in improving the magnetic properties of ferrite nanoparticles, and the magnetic saturation value is 54.23 emu/g. Based on these results, the electrochemical method can be used as an efficient and low-cost synthetic method to make iron oxide nanoparticles doped with lanthanum.

A Zn-based metal–organic framework (Zn-MOF) was synthesized by a novel electrodeposition method. The prepared Zn-MOF was characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy techniques. The supercapacitive behavior of synthesized MOF was examined using cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) measurements in 3 M KOH. SEM images confirmed that Zn-MOF is composed of layered cuboid structure properly attached on to nickel foam substrate. Electrochemical behaviors of the Zn-MOF/Ni foam were also evaluated through GCD tests, which showed high specific capacitance of 288 F g–1 at the current density of 2 A g–1. The outcomes showed great potential of fabricated Zn-MOF as a high-performance electrode material for electrochemical supercapacitors.

In this study, the effect of different substitutions (Eu, Ce, Al, and Bi) on the structural and magnetic properties of Fe3O4 is investigated. All samples were synthesized with the cathodic electrochemical deposition method. The structural properties and surface morphology are investigated by  XRD and FESEM analyses. Structural analysis of the samples showed the formation of a single-phase structure with an Fd-3m space group. The results also showed that the lattice constant and the cell volume increase by increasing the substituted ion's radius. The results of surface morphology of the samples also showed that with increasing substituted ion radius, the average diameter of the samples increases. For BiFe2O4, EuFe2O4, CeFe2O4, and AlFe2O4 samples, the mean diameter was obtained at 50.038 (±13.60)nm, 47.95 (±9.62)nm, 36.06 (±8.29)nm, and 45.72 (±5.39)nm, respectively. And, the magnetic properties of the samples were investigated by VSM analysis. The study of the magnetic properties of the samples shows the superparamagnetic behavior for all samples. Also, the results show that substituting Fe ions with larger radii ions leads to a decrease in saturation magnetization (Ms) and residual magnetization (Mr).

In this paper, polymer grafted nickel-doped iron oxide nanoparticles are fabricated via an easy, one-step and fast electrochemical procedure. In the deposition experiments, iron(II) chloride hexahydrate, iron(III) nitrate nonahydrate, nickel chloride hexahydrate, and dextran were used as the bath composition. Dextran grafted nickel-doped iron oxides (DEX/Ni-SPIOs) were synthesized with applying direct current (dc) of 10 mA cm–2. The magnetite crystal phase, nano-size, Ni doped content, and dextran grafting onto SPIOs were verified through X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses. Magnetic evaluation through vibrating-sample magnetometer (VSM) proved that the DEX/Ni-SPIOs product have superparamagnetic behavior with exhibiting the high saturation magnetization and negligible Ms and Hci values. Based on the obtained results, it was confirmed that the prepared dextran grafted Ni-SPIOs have suitable physico-chemical and magnetic properties for both therapeutic and diagnostic aims.

In this paper, a rapid and room temperature electrochemical method is introduced in preparation of Ni doped iron oxide nanoparticles (Ni-IONs) grafted with ethylenediaminetetraacetic acid (EDTA) and polyvinyl alcohol (PVA). EDTA/Ni-IONs and PVA/Ni-IONs samples were prepared through base electro-generation on the cathode surface from aqueous solution of iron(II) chloride, iron(III) nitrate and nickel chloride salts with EDTA/PVA additive. Uniform and narrow particle size Ni-IONs with an average diameter of 15 nm was achieved. Ni doping into the crystal structure of synthesized IONs and also surface grafting with EDTA/or PVA were established through FT-IR and EDAX analyses. The saturation magnetization values for the resulting EDTA/Ni-IONs and PVA/Ni-IONs were found to be 38.03 emu/g and 33.45 emu/g, respectively, which proved their superparamagnetic nature in the presence of applied magnetic field. The FE-SEM observations, XRD and VSM data confirmed the suitable size, crystal structure and magnetic properties of the prepared samples for uses in biomedical aims.

In this research, Co-doped Fe3O4/NH2-graphene nanocomposite is produced by direct current electrodesotion technique from an aqueous electrolyte containing the iron/cobalt chloride/nitrate salts and amine-functionalized porous graphene. The applied electrochemical parameters were i=5 mA/cm2, Tbath=25oC and tdeposition= 15 min. The electrochemical growth of magnetic particles onto graphene layers and formation of Co-IONPs/f-PG composite were tuned through XRD, FT-IR, FE-SEM, VSM and EDAX analyses. The magnetite phase and particle morphology of the deposited iron oxide onto graphene layers was indicated by XRD pattern and FE-SEM images. The cobalt content of deposited iron oxide was clearly revealed in the EDAX data. The magnetic measurement by vibrating sample magnetometer (VSM) technique exhibited superparamagnetic nature with saturation magnetization and retentivity values of 47.65 emu g–1 and 2.26 emu g–1 for the electro-synthesized magnetic nanocomposite. In final, direct cathodic electrodeposited is proposed as simple procedure for production of iron oxides with various graphene-based materials.

Development of a facile synthesis rout for preparation of polymer coted, metal ion doped magnetic nanoparticles, which have proper magnetic and physicochemical properties for bio-medical uses, is one of the most active research areas in advanced magnetic nano-materials. In this work, we demonstrate an easy electrochemical method for fabrication of PEG-coated Zn2+ or Gd3+ doped magnetic iron oxides (i.e. PEG/Zn-MIOs and PEG/Gd-MIOs). Characterization of the synthesized MIOs was carried out by X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FTIR), Field-emission electron microscopy (FE-SEM), thermal gravimetric analysis (TGA), and vibrating sample magnetometry (VSM) analyses. The XRD and EDAX analyses proved that the electro-synthesized MIOs were magnetite (Fe3O4) doped with 8.6% Zn2+ and/or 19.7% Gd3+. The PEG layer on the Zn-MIOs and/or Gd-MIOs surface was evidenced by FT-IR. FE-SEM showed a spherical morphology with average diameters of 20 nm and 25 nm for PEG/Zn-MIOs and PEG/Gd-MIOs, respectively. TGA data demonstrated that the PEG content of Gd-MIOs was about 10% by weight. Superparamagnetic nature of both prepared magnetic powders was verified by VSM measurements. In final, the analyses results supported that the prepared magnetic nano-particles have suitable size, crystal phase, surface layer and magnetism for bio-medical uses.

Magnetic particles i.e. Fe3O4 nanoparticles have received great attention because of their potential biomedical applications like as MRI contrast agent, hyperthermia and biosensing magnetic labels. For these biomedical applications, Fe3O4 nanoparticles particles must have proper surface coatings and also acquire superparamagnetic properties with relatively high Ms values. Here, we performed Gd doping of iron oxide particles and their in situ surface modification through an electrochemical strategy. The prepared particles were examined using XRD, IR, TG, FE-SEM and EDAX analyses and their covering with starch and doping by Gd cations were approved. VSM data further proved the superparamagnetic behavior of the electrosynthesized iron oxide particles.

Here we describe a simple and novel electrochemical synthesis for preparation of Mn doped iron oxide nanoparticles (MIOs) and their surface coating with saccharides (i.e. glucose, sucrose and starch). The electrochemical preparation of MIOs samples were carried out in a two-electrode electrochemical set up including graphite anode and stainless steel cathode. The surface coating with saccharide agents was also performed in the same set up and simultaneously with the formation of iron oxide particles on the cathode surface. The fabricated MIOs were specified through FT-IR, FE-SEM, XRD, DSC-TGA, and VSM analyses. The structural data obtained by XRD proved the magnetite (Fe3O4) crystal phase of samples, and FT-IR and TG data showed the Mn doping and saccharide coat on the surface of the deposited MIONs. The FE-SEM observations and EDS data confirmed the particle morphology and magnetite chemical composition as well as Mn ions doping into the MIONs. The superparamagnetic nature and suitable magnetic ability (i.e. high saturation magnetization, negligible remanent magnetization and coercivity) for the fabricated MIONs were also assessed though vibrating sample magnetometer (VSM) results. These characters of the electrosynthesized sample provided their suitability for biomedical applications.

In this paper, Ni2 doped magnetite nanoparticles/graphene oxide composite are fabricated through an electrochemical synthesis procedure for the first time. The electrosynthesis procedure is based on the electrochemical growth of iron oxide nanoparticles onto the graphene oxide sheets electrophoretically deposited on the cathode electrode. An aqueous solution of iron nitrate nonahydrate (0.3 g), iron chloride tetrahydrate (0.1 g), nickel nitrate hexahydrate (0.1 g) and 0.03 g dispersed graphene oxide was used as the electrosynthesis bath. The X-ray diffraction pattern of the prepared composite revealed that it has magnetite crystal structure. The particle morphology, graphene oxide content and Ni2 cation doping were also confirmed through FE-SEM observations, EDS and FT-IR analyses. The superparamagnetic nature of the fabricated composite was determined from M-H curve and magnetic data obtained by vibrating sample magnetometer (VSM) analysis. The NiFe3O4/GO composite showed magnetic data of Ms=47.03 emug–1, Mr=0.14 emug–1 and Hci=3.76 G. In final, the cathodic electro-synthesis is proposed as a facile electrochemical technique for the fabrication of metal cations doped magnetite NPs/ graphene oxide nanocomposite.

Cd2 doped iron oxide nanoparticles (Cd-IONs) with magnetite crystal structure and 10-20 nm sizes were prepared through cathodic electro-synthesis (CES) method. In this procedure, IONs are galvanostatically deposited on stainless steel cathode with applying simple electrochemical conditions. The prepared both IONs were used as supercapacitor electrode material and their performances were determined through cyclic voltammetry (CV) and galvanostat charge-discharge (GCD) tests. The Cd-IONs sample exhibited specific capacitance as high as 206 F g−1 and cycling stability of 93.9% after 2000 cycling at 0.5 A g−1. The electrochemical data confirmed the proper capacitive ability of the Cd-IONs.

In this research, a simple and efficient cathodic electrochemical deposition (CED) route wasdeveloped for the preparation of magnetite nanoparticles (NPs) in an aqueous media. Thesurface of magnetite NPs was also coated for the first time via an in situ procedure during theCED process. In this method, initially, the Fe3O4 NPs (with size ~10 nm) were prepared from theFe2+/Fe3+ chloride bath through CED process. Then, dextran as the coating agent was coatedon the surface of Fe3O4 NPs during the CED process. The prepared NPs were characterizedby different techniques such as XRD, FE-SEM, TEM, IR, TGA, DLS and VSM. The XRD resultsproved the pure magnetite i.e. Fe3O4 crystal phase of the prepared samples. Morphologicalobservations through FE-SEM and TEM revealed particle morphology with nano-sizes of 8nm and 12 nm for the naked and dextran coated NPs, respectively. The dextran coat on thesurfaces of NPs was confirmed by FT-IR and DSC-TGA analyses. The average hydrodynamicdiameters of 17 nm and 54 nm were measured from DLS analysis for the naked and dextrancoated NPs, respectively. The magnetic analysis by VSM revealed that prepared NPs havesuperparamagnetic behavior, i.e. Ms=82.3 emu g–1, magnetization Mr=0.71 emug–1 and Ce=2.3Oe for the naked NPs, and Ms=43.1 emu g–1, Mr=0.47 emu g–1 and Ce=0.81Oe for the dextrancoated NPs. These results implied that this electrochemical strategy can be recognized as aneffective preparation method of polymer coated Fe3O4 NPs.

Superparamagnetic Fe3O4 nanoparticles double coated with poly(vinylpyrrolidone)/polyvinyl chloride polymers were successfully fabricated by a facile cathodic electrochemical deposition (CED) method. In this method, in situ polymer coating ofthe surface of Fe3O4 nanoparticles was achieved through electrodeposition process. The evaluation by XRD analysis confirmed that the electrodeposited nanoparticles are composed of pure phase of iron oxide i.e. magnetite (Fe3O4). The structure and composition of the prepared nanoparticles were characterized by SEM, TEM, DLS, XRD, FTIR, and TG analysis. The DLS analysis revealed that the bare and prepared polymer coated Fe3O4 nanoparticles have size of 20nm and 62nm, respectively. The polymer coated nanoparticles with having 15nm in size, suitable magnetization value (Ms=22 emu/g), and negligible coercivity (Ce=0.42 emu/g) and remanence (Mr=1.1 Oe) are proper candidate for biomedical applications. This electrochemical strategy is proposed as facile and efficient for preparation and double coating of Fe3O4 nanoparticles.