Nanocomposite Elements Research Articles

Synthesis and Characterization of CuO Nanocomposites Doped with Cr <sup>3+</sup> and Mn <sup>2+</sup> for Efficient Photodegradation of Organic Dyes (MB & MO)

Nanocomposites CuO/CuCr 2 O 4 /CuSO 4 (1) and CuO/CuMn 2 O 4 /CuSO 4 (2) were synthesized by chemical deposition, and their structural, morphological, optical, and thermal properties were investigated by FTIR, XRD, FESEM, TEM, EDX, UV-Vis DRS, and TG-DTA. From the analysis of the obtained data, analysis of FESEM, TEM, and EDS data revealed that nanocomposites have a sheet structure and that the elements are homogeneously scattered throughout the structure. The doped Cr and Mn elements in nanocomposites (1) and (2) form the CuCr 2 O 4 and CuMn 2 O 4 spinel structures, respectively. Thermal analysis shows that the compounds have a high thermal stability. Apart from that, the photocatalytic activity of the compounds is very effective in cationic (MB) and anionic (MO) degradation colored pollutants in the presence of H 2 O 2 and under sunlight. A kinetic study showed that degradation follows the first-order kinetics; therefore, these nanocomposites are good candidates for color degradation with good efficiency in wastewater treatment.

A nanocomposite prepared from platinum particles, polyaniline and a Ti3C2 MXene for amperometric sensing of hydrogen peroxide and lactate.

A nanocomposite consistingof platinum particles, polyaniline and Ti3C2 MXene (Pt/PANI/MXene) was used tomodify a screen-printed carbon electrode (SPCE) to obtain sensors for hydrogen peroxide and lactate. This nanocomposite was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) to determine the physical morphologies and the nanocomposite elements. The modified electrode exhibited the improved current response towards hydrogen peroxide (H2O2) compared with an unmodified electrode and provided a low detection limit of 1.0μM. When lactate oxidase was immobilized on the modified electrode, the electrode responded to lactate via the H2O2 generated in the enzymatic reaction. The lactate assaywas performed by amperometry at a constant potential of +0.3V (vs. Ag/AgCl). The linear range was found to be from0.005 to 5.0mM with a detection limit of 5.0μM for lactate. Ultimately, this biosensor was used for the determination of lactate in milk samples with high stability and reliability. Graphical abstractSchematic representation of a novel platinum particles/polyaniline/MXene nanocomposite (Pt/PANI/MXene) for screen-printed carbon electrode (SPCE) modification to enhance the specific surface area for immobilization of lactate oxidase (LOx) and use as enzymatic biosensor for lactate determination in milk sample.

Photocatalytic oxidation for removal of gases toluene by TiO2-CeO2 nanocomposites under UV light irradiation

Simple sol-gel method has used to synthesize TiO2-CeO2 nanocomposites. XRD analysis carried out to determine the phase and structural properties of the synthesized nanocomposites. Thermal and gravimetric stability of the samples were determined by TGA. The optical spectroscopic study revealed that the nanocomposites show the shifting of band edge towards higher wavelength with an increase in the CeO2 content in nanocomposites as compared to pure TiO2. Morphology of the synthesized nanocomposites was confirmed by FE-SEM and TEM analysis. Synthesized nanomaterials are in spherical with particle sizes in the range 10–20 nm. The HR-TEM image showed the formation of the heterojunction between CeO2 and TiO2 NPs and their elemental composition was confirmed by EDS. Surface chemical bonding states and the electronic valence band positions of the elements in nanocomposites were determined by XPS analysis. Photoluminescence study revealed the effect of CeO2 concentration on photogenerated electron-hole pairs in TiO2 nanoparticles. Photocatalytic activity of synthesized nanomaterials was studied by decomposition of toluene gas with irradiation of UV light. Revealed that nanocomposites with TiO2:CeO2 ratio of 3:1 had the highest photocatalytic efficiency as compared to the other nanocomposites and pure TiO2 and CeO2 nanoparticles. Therefore, the results confirmed that the coupling of TiO2 with CeO2 absorb the photon energy and generates reactive oxygen species, which are easily transferred to CeO2, causing enhances the separation of the electron-hole pair and an improved the photocatalytic activity of the nanocomposites.

Dielectric and Electrical Properties of WS2 Nanotubes/Epoxy Composites and Their Use for Stress Monitoring of Structures

The dielectric and electrical characteristics of the semiconductive WS2 nanotubes/epoxy composites were studied as a function of the nanotubes concentration and the pressure applied during their molding. In addition, the ability of WS2 nanotubes to serve as stress sensors in epoxy based nanocomposites, for health-monitoring applications, was studied. The nanocomposite elements were loaded in three-point bending configuration. The direct current was monitored simultaneously with stress-strain measurements. It was found that, in nanocomposites, above the percolation concentrations of the nanotubes, the electrical conductivity increases considerably with the applied load and hence WS2 nanotubes can be potentially used as sensors for health monitoring of structural components.