Nguyen Duc Cuong

Fe3O4/Reduced Graphene Oxide Nanocomposite: Synthesis and Its Application for Toxic Metal Ion Removal

The synthesis of reduced graphene oxide modified by magnetic iron oxide (Fe3O4/rGO) and its application for heavy metals removal were demonstrated. The obtained samples were characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and magnetic measurement. The results showed that the obtained graphene oxide (GO) contains a small part of initial graphite as well as reduced oxide graphene. GO exhibits very high surface area in comparison with initial graphite. The morphology of Fe3O4/rGO consists of very fine spherical iron nanooxide particles in nanoscale. The formal kinetics and adsorption isotherms of As(V), Ni(II), and Pb(II) over obtained Fe3O4/rGO have been investigated. Fe3O4/rGO exhibits excellent heavy metal ions adsorption indicating that it is a potential adsorbent for water sources contaminated by heavy metals.

Monodisperse Uniform CeO2 Nanoparticles

Ceria nanostructure-based catalysts have attracted much attention in recent years because of their unique physiochemical properties. Herein, we have presented a simple two-phase approach for the synthesis of ceria nanocrystals. Structural and morphological characterization by XRD and TEM showed that the as-synthesized monodisperse CeO2 nanoparticles NPs had cubic fluorite crystal structure with average particle size about 6.75 nm. The effects of hydrothermal temperature, annealing time, and concentration of cerium nitrate on the nanostructures of the products were also investigated and discussed. In addition, the CeO2 nanocrystals proved to be an effective catalyst for the photodegradation of blue methylene under UV illumination.Ceria nanostructure-based catalysts have attracted much attention in recent years because of their unique physiochemical properties. Herein, we have presented a simple two-phase approach for the synthesis of ceria nanocrystals. Structural and morphological characterization by XRD and TEM showed that the as-synthesized monodisperse CeO 2 nanoparticles (NPs) had cubic fluorite crystal structure with average particle size about 6.75 nm. The effects of hydrothermal temperature, annealing time, and concentration of cerium nitrate on the nanostructures of the products were also investigated and discussed. In addition, the CeO 2 nanocrystals proved to be an effective catalyst for the photodegradation of blue methylene under UV illumination.

A novel approach for synthesis of hierarchical mesoporous Nd 2 O 3 nanomaterials

Abstract A novel route to the fabrication of hierarchical mesoporous Nd 2 O 3 nanostructures including nanospheres and nanoporous network was described. Their structure and morphology evolution of the as-synthesized materials were determined by various techniques such as scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transforminfrared spectra, nitrogen adsorption/desorption isotherm, and a formation mechanism was proposed. The results revealed that the Nd 2 O 3 nanospheres had the diameter of 300 nm, which were composed of small primary nanoparticles (NPs) with the size of 10 nm. The nanoporous structure also formed the NPs of ca . 10 nm which were connected with each other to form a three-dimensional (3D) texture. This simple and mild approach to fabricate hierarchical mesoporous Nd 2 O 3 nanostructures could be easily scaled up and potentially extended to synthesize other oxide hierarchical structures.

Electrochemical Determination of Paracetamol Using Fe3O4/Reduced Graphene-Oxide-Based Electrode

The synthesis of magnetic iron oxide/reduced graphene oxide (Fe3O4/rGO) and its application to the electrochemical determination of paracetamol using Fe3O4/rGO modified electrode were demonstrated. The obtained materials were characterized by means of X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), and magnetic measurement. The results showed that Fe3O4/rGO composite exhibited high specific surface area, and its morphology consists of very fine spherical particles of Fe3O4 in nanoscales. Fe3O4/rGO was used as an electrode modifier for the determination of paracetamol by differential pulse-anodic stripping voltammetry (DP-ASV). The preparation of Fe3O4/rGO-based electrode and some factors affecting voltammetric responses were investigated. The results showed that Fe3O4/rGO is a potential electrode modifier for paracetamol detection by DP-ASV with a low limit of detection. The interfering effect of uric acid, ascorbic acid, and dopamine on the current response of paracetamol has been reported. The repeatability, reproducibility, linear range, and limit of detection were also addressed. The proposed method could be applied to the real samples with satisfactory results.

Preparation and characterization of superparamagnetic Fe3O4-chitosan nanocomposites

In this study, superparamagnetic nanocomposite Fe 3 O 4 -chitosan has been prepared by two step method. The Fe 3 O 4 nanoparticles were prepared by a co-precipitation process and subsequently coated with chitosan. The magnetite nanoparticles and chitosan coated magnetic nanoparticles were characterized by XRD, IR and TEM. The magnetic properties were measured with homemade vibrating sample magnetometer (VSM) and evaluated in terms of saturation magnetization and coercivity. The results revealed that typical iron oxide nanoparticles were Fe 3 O 4 with a core diameter of 15-20 nm. Magnetie nanoparticles were formed inside the chitosan matrix through possible binding of iron ions to NH 2 group of chitosan. The Fe 3 O 4 -chitosan nanoparticles with core-shell structure exhibit superparamagnetic properties and highly dispersed nano magnetite particles with diameters around 15 nm. Keywords: Fe 3 O 4 , chitosan, superparamagnetic nanocomposite, two step method.

Synthesis, characterization, and gas-sensing properties of alpha-Fe2O3 prepared from Fe3O4-alginate

In this study, nanocomposite Fe 3 O 4 –alginate has been prepared by so-called two step method. The crystal structures and morphologies of as-synthesized nanopaticles (NPs) were characterized X-ray diffraction, and scanning electron microscopy. The surface states of Fe 3 O 4 -alginate NPs were characterized by Fourier transform infrared spectra. a-Fe 2 O 3 was fabricated from the nanocomposite Fe 3 O 4 -alginate by heat treatment in air atmosphere at 600 o C and their gas sensing properties were investigated. The performance of the a-Fe 2 O 3 in the detection of toxic and flammable gases such as carbon oxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe 2 O 3 based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. Keywords: Fe 2 O 3 , Fe 3 O 4 , gas sensor, alginate.