Facile Synthesis Bi2Te3 Based Nanocomposites: Strategies for Enhancing Charge Carrier Separation to Improve Photocatalytic Activity

Varying structure Bi2Te3-based nanocomposite powders including pure Bi2Te3, Bi2Te3/Bi core−shell, and Bi2Te3/AgBiTe2 heterostructure were synthesized by hydrothermal synthesis using Bi2S3 as the template and hydrazine as the reductant. Successful realization of Bi2Te3-based nanostructures were concluded from XRD, FESEM, and TEM. In this work, the improvement in the performance of the rhodamine B (RhB) decomposition efficiency under visible light was discussed. The Bi2Te3/AgBiTe2 heterostructures revealed propitious photocatalytic performance ca. 90% after 60 min. The performance was over Bi2Te3/Bi core-shell nanostructures (ca. 40%) and more, exceeding pure Bi2Te3 (ca. 5%). The reason could be scrutinized in terms of the heterojunction structure, improving the interfacial contact between Bi2Te3 and AgBiTe2 and enabling retardation in the recombination rate of the photogenerated charge carriers. A credible mechanism of the charge transfer process in the Bi2Te3/AgBiTe2 heterostructures for the decomposition of an aqueous solution of RhB was also explicated. In addition, this work also investigated the stability and recyclability of a Bi2Te3/AgBiTe2 heterojunction nanostructure photocatalyst. In addition, this paper anticipates that the results possess broad potential in the photocatalysis field for the design of a visible light functional and reusable heterojunction nanostructure photocatalyst.

Adsorption of Anionic Dyes from Wastewater onto Magnetic Nanocomposite Powders Synthesized by Combustion Method

In the present study, new magnetic nanocomposites were successfully prepared by combustion method, characterized by X-ray diffraction, Fourier transform infrared spectroscopy, magnetic measurements, N2 adsorption–desorption thermal analysis, and scanning electron microscopy, and tested as adsorbents for the removal of anionic dyes (Acid Yellow 42 and Acid Red 213) from aqueous solutions. The influence of process variables solution pH, adsorbent dose, initial dye concentration and temperature on the adsorption was evaluated. The best kinetic model that fitted with experimental data was a pseudo-second order model, and the equilibrium data were correlated by Langmuir isotherm model for the investigated dyes. Maximum removal efficiencies of 98.54% and 97.58% was obtained for Acid Yellow 42 and Acid Red 213, respectively, indicating the superior adsorption capacity of the new synthesized magnetic nanocomposites. The thermodynamic parameters indicated the spontaneous and endothermic nature of the adsorption process.

Effect of Mechanical Alloying on Structural and Electrical Properties of (P2O5)(x)-(Y2O3)(0.03)-(ZrO2)(0.97) Electrolyte

Pentavalent phosphorous oxide doped yttria-stabilized zirconia (P2O5)X-(Y2O3)0.03-(ZrO2)0.97 with x=0.06 mol.% was achieved via an economical technique using mechanical alloying (MA) technique. Three types of nanocomposite powders of electrolyte were produced by high-energy ball milling with different milling times. The phases of synthesized electrolyte powders and sintered electrolytes were illustrated by X-ray diffraction (XRD). The average particle sizes of powders indicated around (360, 245, and 48) nm at milling duration (1, 10, and 45) hrs, respectively. The XRD analysis results of 1 h MA electrolyte powder obtained tetragonal ZrO2, while the 45 h MA electrolyte manifested a minority phase of monoclinic ZrO2. Then, the XRD of the sintered electrolyte with the optimum electrical properties appeared two phases. The major phase of the tetragonal zirconium yttrium oxide and a minor phase was a monoclinic zirconium oxide. The average grain sizes of the three types of the sintered manufacturing electrolytes were (7.638, 2.642, and 1.245 µm) after the mechanical alloying duration of (1, 10, and 45) hrs, respectively and sintered at 1873 °K. The DC conductivity (σ) studied corresponded to the influence of milling times on the microstructure for each sintered electrolyte. From the results, the synthesized sintered electrolyte with a long MA duration gave a maximum DC (σ) 1.03E-1S.m. And, the DC conductivity (σ) was 1.11E-02 of electrolyte produced with 10 hr mechanical alloying. Otherwise, the lower DC conductivity got with the electrolyte prepared in the lowest milling duration was 8.9 E-2 S.m.

Study of ZnO-CNT Nanocomposites in High-Pressure Conditions

Recently, carbon nanotubes (CNTs) have been used extensively to develop new materials and devices due to their specific morphology and properties. The reinforcement of different metal oxides such as zinc oxide (ZnO) with CNT develops advanced multifunctional materials with improved properties. Our aim is to obtain ZnO-CNT nanocomposites by in situ hydrothermal method in high-pressure conditions. Various compositions were tested. The structure and morphology of ZnO-CNT nanocomposites were analyzed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry—thermogravimetry (DSC-TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). These analyses showed the formation of complex ZnO-CNT structures. FT-IR spectra suggest possible interactions between CNT and ZnO. DSC-TG analysis also reveals the formation of some physical bonds between ZnO and CNT, through the appearance of endothermic peaks which could be assigned to the decomposition of functional groups of the CNT chain and breaking of the ZnO-CNT bonds. XRD characterization demonstrated the existence of ZnO nanocrystallites with size around 60 nm. The best ZnO:CNT composition was further selected for preliminary investigations of the potential of these nanocomposite powders to be processed as pastes for extrusion-based 3D printing.

Synergistic Strengthening Effect of Reinforcing Spark Plasma Sintered Al-Zn-TiC Nanocomposites with TiC Nanoparticles

In this investigation, Al-10Zn-TiC nanocomposite powders were prepared by varying the reinforcement content in wt.% via mechanical alloying in order to fabricate bulk samples via spark plasma sintering technique. The grain size exhibited in bulk samples was 17 ± 08 μm in 10 wt% TiC reinforced nanocomposites. The introduced TiC nanoparticles were improved the load carrying ability of the final product. The advanced microscopic studies such as X-ray diffraction analysis, SEM, HR-TEM along with the ring pattern were analysed to ensure the phases and their distribution of reinforced nanoparticles in the Al matrix. The XRD results revealed the formation of TiC present in the matrix, and SEM analysis conveys the uniform distribution and absence of clustering among the reinforcement particles; TEM results depicted the clear interface between the matrix and TiC nanoparticles. The mechanical properties such as hardness and compression studies were carried out in the bulk specimens. The obtained results confirmed the nanocomposites exhibit higher strength which was not only due to decrease in grain size but also due to the occurrence of different strengthening mechanisms such as grain boundary, Orowan and thermal expansion coefficient mismatch strengthening commensurate with the nanoscale TiC addition.

Fast Solution Synthesis of NiO-Gd0.1Ce0.9O1.95 Nanocomposite via Different Approach: Influence of Processing Parameters and Characterizations

The synthesis of the nickel oxide-gadolinium doped ceria (NiO-GDC with 65:35 wt.%) nanocomposite powders with a stoichiometry of Gd0.1Ce0.9O1.95 was performed via fast solution combustion technique; using three different mixing methods: (i) CM (metal cations in an aqueous solution), (ii) HM (hand mortar), and (iii) BM (ball milling). The nanocomposite powders were calcined at 700 °C for 2 h and characterized by Transmission Electron Microscopy (TEM), X-ray fluorescence (XRF), and X-ray Diffraction XRD. The TEM and XRD analyses evidenced the well-dispersed NiO and GDC crystallites with the absence of secondary phases, respectively. Later, the calcined powders (NiO-GDC nanocomposites) were compacted and sintered at 1500 °C for 2 h. The microhardness of the sintered nanocomposites varies in accordance with the synthesis approach: a higher microhardness of 6.04 GPa was obtained for nanocomposites synthesized through CM, while 5.94 and 5.41 GPa were obtained for ball-milling and hand-mortar approach, respectively. Furthermore, it was observed that regardless of the long time-consuming ball-milling process with respect to the hand mortar, there was no significant improvement in the electrical properties.