mustafa aghazadeh

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 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).

The aim of this study was to investigate the inhibitory effect of a prepared complex on the magnetic iron oxide nanoparticles to increase the surface resistance of metals against corrosion. A new chelating agent was prepared from a coupling of xanthate and chloroacetamide and then grafted on surface of iron oxide nanoparticles that were synthesized by co-precipitation method. The surface of the nanoparticles was coated with silica to stabilize against oxidation as well as to prevent their accumulation, and then this surface was modified and functionalized by amine groups. Then the prepared complex was characterized by FT-IR, SEM and NMR and its effect on metal surface corrosion in hydrochloric acid medium was investigated using electrochemical impedance test (EIS). The results were evaluated in terms of increasing inhibitory concentration, decreased surface roughness and load transfer layer resistance at the electrode surface. The results showed that with increasing the inhibitor concentration, the surface roughness decreased and the resistance of the charge transfer layer at the electrode surface increased to 356.57 Ω cm2 and the best result was obtained at a concentration of 100 ppm of the inhibitor.

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 paper, with manganese doping into the crystal structure of iron oxide and then surface coating with dextran/PEI layers, two novel types of superparamagnetic particles are fabricated. A simple one-step cathodic electrochemical synthesis is developed for preparation of these magnetic nanoparticles. The deposition and surface coating are simultaneously performed from the dextran or PEI added aqueous solution of 0.1M Fe(II) chloride, 0.2M Fe(III) nitrate and 0.05M manganese nitrate. FT-IR, EDAX and FE-SEM analyses showed nano-size of the prepared iron oxide particles and the polymer layers onto their surface. Negligible remanence and coercivity values exhibited by the prepared iron oxide particles verified their excellent superparamagnetic behavior. Based on the analyses results, it was proven that the prepared magnetic particles are good candidates for biomedical applications.

Supercapacitors (SCs) are promising energy sources with high power densities. In the recent years, many efforts have been made to enhance the low energy density of SCs through improvement of the electrode materials. As electrode materials, metal oxides/hydroxides (MOHs) and their composites usually offer high energy densities as a result of their high theoretical capacitances. Up to now, various synthetic methods have been developed for preparing MOHs. In this regards, cathode electrodeposition through base electrogeneration has been intensively used as a one-step simple technique for obtaining various nanostructures of MOHs composites as high-performance SC electrode materials. In this paper, the reports on the fabrication of MOHs-based nanomaterials through the CED method and their super-capacitive abilities have been reviewed.

In this work, PEI and PVC grafted Ni doped superparamagnetic iron oxide (i.e. PEI/Ni-SPIOs and PVC/Ni-SPIOs) were synthesized on steel sheet though galvanostatic (constant current) deposition mode. Structural and morphological properties of the fabricated PEI/Ni-SPIOs and PVC/Ni-SPIOs samples were studied and the results indicated the successful synthesis of polymer grafted iron oxide nanoparticles. The size of prepared particles was about 20 nm. Thermogravimetric data showed 7.2 wt % PEI and 6 wt % PVC coated onto the surface of Ni-SPIOs particles. The magnetite crystal phase of samples was proved via XRD and IR data. In addition, the obtained results from vibrating sample magnetometer analysis showed that the fabricated samples exhibit low residual magnetization values (i.e. Mr=0.95 and Mr=0.53 emu/g, respectively, for PVC and PEI grafted Ni-SPIOs), which revealed their suitability for biomedical uses.

Herein, a very simple and scalable electrochemical strategy is reported to fabricate reduced graphene oxide (rGO)-Mn3O4 nanoparticles composite for supercapacitors. First, graphene oxide is directly produced via Hummers method, and dispersed in manganese nitrate aqueous solution. The rGO-Mn3O4 particles nanocomposite is then prepared through electrochemically decoration of Mn3O4 nanoparticles onto reduced graphene oxide (rGO) sheets. The formation of composite is explained by electrophoretic/electrochemical deposition (EPD/ECD) mechanism. The as-prepared rGO-Mn3O4 nanocomposite is characterized by XRD, IR, FE-SEM and TEM techniques. These analyses results specified the co-deposition of manganese oxide particles and rGO sheets on the cathode electrode. The charge storage ability of the fabricated nanocomposite as electrode material for supercapacitors was studied using cyclic voltammetry and charge-discharge techniques. The obtained electrochemical data indicated that the rGO-Mn3O4 nanocomposite enable to provide specific capacitance of 364 F g−1 at 2 A g−1 and 86.3% of its initial capacity after 5000 charge/discharging.

Ni(OH)2 /mesoporous carbon composite was successfully deposited onto Ni foam by electrochemical deposition under ambient conditions. Using a simple electrochemical deposition (ECD) method, nickel hydroxide nanoparticles (NPs) was electrochemically formed onto mesoporous carbon structures (CMK). The surface morphology and crystallinity properties of the synthesized Ni(OH)2 NPs/CMK onto Ni foam are characterized by physicochemical techniques of XRD and FE-SEM. Furthermore, the deposited β-Ni(OH)2 NPs/CMK on Ni foam reveal superior energy storage ability in 1M KOH electrolyte as a binder-free electrode for pseudocapacitors. Compared to the Ni(OH)2@NF electrode, the composite sample (Ni(OH)2/CMK@ NF electrode) exhibit a relatively high electrochemical performance (Cs=1224 F g–1 at 2 A g–1) and stable Cs retention (94%) after 3000 GCD cycling, which was ascribed to the electronic and ionic synergisms between β-Ni(OH)2 NPs and mesoporous carbon material of Ni electrode. This cost-effective and in situ electrochemical growth of metal hydroxide nanostructures on carbonous structures may be useful for advanced energy storage device applications.

Pristine crystalline superparamagnetic nanoparticles (SPNs) of magnetite (Fe3O4) were prepared from an additive-free aqueous solution of iron(III) nitrate salt though a novel one-pot electrodeposition method. The prepared nanoparticles were characterized by XRD, IR, VSM, DLS and FE-SEM. The SPNs were further grafted by poly(N-vinyl-2-pyrrolidone) during their deposition process. The PVP-grafting via electrochemical route was confirmed by IR, DSC-TGA and DLS analyses. The analyses results confirmed the proper phase (i.e. pristine magnetite), size (about 10 nm) and excellent super-paramagnetic nature (Ms=48.57emu g–1, Mr≈0.038 emu g–1 and Ce~1.35G) of the prepared PVP-grafted Fe3O4 nanoparticles for biomedical applications.

Electrochemical synthesis followed by heat-treatment is a facile and easy method for preparation of nanostructured metal oxides. Herein we report nanostructured Mn5O8 prepared through pulse cathodic deposition followed by heat-treatment for the first time. For the preparation of Mn5O8 nanorods, pulse cathodic electrodeposition was first done from 0.005M Mn(NO3)2 at the current density of 5 mA cm-2 which yield Mn3O4 precursor. Then, heat-treatment of the deposited precursor was performed to obtain final Mn5O8 product. The structural and morphological properties of the prepared product were investigated by XRD, FT-IR, SEM and TEM techniques. The analysis results revealed that the prepared sample has pure Mn5O8 composition with rod morphology at nanoscale. Mechanism of deposit formation during pulse deposition was proposed and discussed. The formation of Mn5O8 nanorods via calcination of Mn3O4 precursor was also studied by thermogravimetric analysis. The results suggested that the cathodic electrodeposition-heat treatment method can be considered as simple and facile route for preparation of Mn5O8 nanorods.

Cerium oxide possess various applications including waste refiner, catalyst, electrolyte in solid state fuel cell, glass decoloring and materials polishing. The use of this material in nanosized form, with high surface area improves its functionality significantly. In this study, ultrafine CeO2 nano-particles were prepared by a simple electrochemical platform. The synthesis experiments were performed from 0.01 M cerium nitrate aqueous electrolyte in the presence of H2O2 and PVP. The asdeposited powder was also calcined 400 °C for 2 h. The morphologies and crystal structures of the prepared powders were examined by means of scanning and transmission electron microcopies (SEM and TEM) as well as X-ray diffraction (XRD), FT-IR and DSC-TGA. These analysis results proved the electro-synthesis of pure crystalline cerium oxide final particles. The high surface area (184.8 m2 g–1) of the prepared nanoparticles was also confirmed through BET analysis. A possible mechanism of CeO2 deposition on the cathode surface was proposed, when the hydrogen peroxide additive played an important role in the formation of hydrous cerium oxide. In final, this simple electrochemical procedure is proposed for mass production of high surface area ultrafine nanoparticles of cerium oxide.

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.

We reported here a simple electro-synthesis procedure to synthesize an extremely high specific surface area (SSA) yttrium oxide (Y2O3) nanopowder. The mesoporous (pore diameter, d≈8 nm) Y2O3 powder was deposited by a two-step process involving the pulse cathodic electro-deposition (PC-ED) of yttrium hydroxide film from nitrate bath at 70 oC temperature followed by calcination at 600 C in air for 3 h. The applied pulse parameters i.e. peak current density, on-time and off-time were Ip=25 mA/cm2, ton=1ms and toff=5ms, respectively. The products were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy methods. The obtained data proved that the fabricated product had pure cubic Y2O3 crystal structure and is composed thin wall-like morphology with SAA value of 243.7 m2/g and mean pore size of 9 nm. From these findings, the PC-ED procedure was proposed for facile fabrication of high-SSA Y2O3 nanopowder.

Gd2O3 nanoparticles were prepared by a two–step process; cathodic electrodeposition followed by heat-treatment method. First, Gd(OH)3 nanoparticles was galvanostatically deposited from nitrate bath on the steel substrate by pulse current (PC) mode. The deposition experiments was conducted at a typical on-time and off-time (ton=1ms and toff=1ms) for 60 min. The electrodeposited precursor was then heat-treated at 600 oC for 3h to obtain oxide product (i.e. Gd2O3). The morphological and structural analyses confirmed that the gadolinium hydroxynitrate nanoparticles with composition of [Gd(OH)2.5(NO3)0.5 yH2O] and uniform size about 10 nm have been prepared during pulse cathodic electrodeposition process. Furthermore, mechanism of the gadolinium hydroxynitrate nanoparticles was explained based on the base (OH–) electrogeneration process on the cathode surface. The morphological observations by SEM and TEM, and structural analyses via XRD and FT-IR revealed that the oxide product is composed of well-dispersed Gd2O3 nanoparticles with pure cubic crystalline structure. It was observed that the calcination process has no effect on the morphology of the Gd2O3 nanoparticles. Mechanism of oxide formation during heat-treatment step was investigated by DSC-TG analysis and discussed in detail. The results of this work showed that pulse current deposition followed by heat–treatment can be recognized as an easy and facile method for preparation of the Gd2O3 fine nanoparticles.

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.

Porous nanostructured Mn3O4 was deposited from 0.005 M manganese nitrate bath using a one-pot cathodic electrodeposition route. The deposition experiments were performed under the direct current mode with applying a current density of 10 mA cm-2. The structural analyses by XRD and FTIR, revealed that the product is composed of pure tetragonal Mn3O4. Morphological observation by SEM and TEM disclosed that the prepared Mn3O4 product is made up of porous plates at nanoscale. BET analysis further revealed that the prepared sample has high surface are of 125 m2/g with mesoporous structure. Electrochemical evaluations by cyclic voltammetry and charge-discharge tests also showed the prepared Mn3O4 to be capable of delivering high specific capacitance values of 328 F g−1, in addition to exhibiting excellent long-term cycling stability (95.9% of initial capacity after discharging 1000 cycles).

Ultrafine M(OH)n (M=La, Gd, Ni and Co) nanoparticles were electrochemically deposited from an additive–free M(NO3)n (0.005 M) low-temperature bath on a steel substrate at the constant current density of 1 mA cm−2. Heat–treatment of the prepared M(OH)n nanoparticles at 700oC led to formation of the oxide nanoparticles. The morphologies, crystal structures and compositions of the prepared products were determined by means of scanning (SEM) and transmission (TEM) electron microscopy as well as X-ray diffraction (XRD) and FT-IR spectroscopy. The results showed that the prepared M(OH)n samples are composed of ultrafine particles with the size of about 5 nm. After heat–treatment, the obtained products were well–crystallized phases of oxide nanoparticles with a size of around 10 nm. It was concluded that low-temperature cathodic electrodeposition offers a facile and feasible way for the preparation of ultrafine particles of metal oxides and hydroxides.

The objectives of this research were to synthesize manganese dioxide nanoparticles and determine their efficiency in the removal of lead from aqueous solutions. Consequently, manganese dioxide nanoparticles were synthesized by the cathode electrochemical deposition method and the effect of pH, contact time, lead concentration and quantity of nanoparticles on lead removal efficiency were investigated through the batch system. A scanning Electron Microscope (SEM), XRD and FTIR were used to characterize the synthesized manganese dioxide nanoparticles. SEM results showed that the diameter of the particles is 30-50 nm and the results also showed that the optimum pH value for adsorption was 6. The adsorption capacity increased and the adsorption efficiency decreased with increasing concentration of lead ions and by reducing the amount of adsorbent. In a study of the adsorption isotherm, experimental data from the Langmuir model to follow. The data obtained in this study showed that the absorption of lead absorption kinetics model obeys the model of Hu and colleagues. The overall results of this study showed that the use of manganese dioxide nanoparticles was a suitable method with high potential for the removal of lead from aqueous solutions.