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Nanostructured Co 3 O 4 was prepared via a simple two-step process: cathodic electrodeposition of cobalt hydroxide from additive free nitrate bath and then heat treatment at 400°C for 3 h. The prepared oxide product was characterized by powder X-ray diffraction, infrared spectroscopy, surface area measurement, scanning electron microscopy, and transmission electron microscopy. Morphological characterization showed that the oxide product was composed of porous nanoplates, and BET measurement displayed that the oxide plates have the average pore diameter and the surface area of 4.75 nm and 208.5 m 2 g -1 , respectively. The supercapacitive performance of the nanoplates was evaluated using cyclic voltammetry and charge-discharge tests. A specific capacitance as high as 393.6 F g -1 at the constant current density of 1 A g -1 and an excellent capacity retention (96.5% after 500 charge-discharge cycles) was obtained. These results indicate that Co 3 O 4 nanoplates can be recognized as high-performance electrode materials.

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In this report, cerium doped-ferrite nanoparticles (Ce–Fe3O4 NPs), a novel ceria nanostructure, were proposed to have intrinsic peroxidase-like activity toward a classic peroxidase substrate in the presence of H2O2.

Cathodic electrochemical deposition (CED) is introduced as an efficient and effective method for synthesis and surface coating of superparamagnetic iron oxide nanoparticles (SPIONs). In this way, bare Fe3O4 nanoparticles were electrosynthesized through CED method from aqueous solution Fe3+ : Fe2+ chloride (molar ratio of 2 : 1). In the next step, the surface of NPs was coated with polyethyleneimine (PEI) and polyethylene glycol (PEG) during the CED procedure, and PEG/PEI coated SPIONs were obtained. The prepared NPs were evaluated by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), and field-emission scanning electron microscopy (FE-SEM). The pure magnetite phase and nanosize (about 15 nm) of the prepared NPs were confirmed by XRD and FE-SEM. The presence of two coats (i.e., PEG and PEI) on the surface of electrosynthesized NPs was proved via FTIR results. The percentage of polymer coat (37.5%) on the NPs surface was provided by TGA analysis. The high magnetization value, negligible coercivity, and remanence measured by VSM indicate the superparamagnetic nature of both prepared NPs. The obtained results confirmed that the prepared Fe3O4 nanoparticles have suitable physicochemical and magnetic properties for biomedical applications.

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