Conversion of a 2D Lepidocrocite-Type Layered Titanate into Its 1D Nanowire Form with Enhancement of Cation Exchange and Photocatalytic Performance.

Layered titanates with one-dimensional (1D) shapes have been an important class of nanomaterials due to their combination of 1D and 2D fascinating properties. Among many layered titanates, lepidocrocite-type layered titanates have significant advantages such as superior intercalation and exfoliation properties, while the synthesis of the 1D-shape forms is still challenging. Here, we report on a facile one-pot hydrothermal conversion of a lepidocrocite-type layered titanate into the corresponding nanowire-shape form. The reaction mechanism involves the decomposition of the starting layered titanate into 1D small segments which assemble into the nanowire. This new nanowire shows properties resulting from the combination of 1D and 2D nanostructural features, excellent cation exchange ability, and high photoinduced charge separation and photocatalytic efficiency. As a demonstration, we evaluate the nanowire as a sequestrating material capable of collecting toxic cations, like Cd2+, from water and photoreducing them (immobilizing them tightly). We find that the nanowire shows an efficient and ultrafast photoimmobilization activity, whereas the starting layered titanate and a benchmark TiO2 photocatalyst (P25) show no activity under the identical conditions. The photoimmobilization rate (within 1 min) is considerably faster than the cation exchange rates reported for state-of-the-art cation exchangers (with no photoimmobilization ability). The nanowire used for photoimmobilization reactions is easily recovered from water by decantation, showing the possible practical use for safe disposal of toxic cations in the environment.

Synthesis and Characterization of Molybdenum- and Sulfur-Doped FeSe.

During the past decade, two-dimensional (2D) layered materials opened novel opportunities for the exploration of exciting new physics and devices owing to their physical and electronic properties. Among 2D materials, iron selenide has attracted much attention from several physicists as they provide a fruitful stage for developing new superconductors. Chemical doping offers a powerful approach to manipulate and optimize the electronic structure and physical properties of materials. Here, to reveal how doping affects the physical properties in FeSe, we report on complementary measurements of molybdenum- and sulfur-doped FeSe with theoretical calculations. Mo0.1Fe0.9Se0.9S0.1 was synthesized by a one-step solid-state reaction method. Crystal structure and morphology were studied using powder X-ray diffraction and scanning electron microscopy. Thermal stability and decomposition behavior in doped samples were studied by thermogravimetric analysis, and to understand the microscopic influence of doping, we performed Raman spectroscopy. First-principles calculations of the electronic structure illustrate distinct changes of electronic structures of the substituted FeSe systems, which can be responsible for their superconducting properties.

Comparative Study between Traditional and Nano Calcium Phosphate Fertilizers on Growth and Production of Snap Bean (Phaseolus vulgaris L.) Plants.

Recently, nanofertilizers are being tested as a new technology, either for soil or foliar applications, to improve food production and with a reduced environmental impact. Nano calcium phosphate (NCaP) was successfully synthesized, characterized and applied in this study. A pot experiment was carried out in two successive seasons in 2016 and 2017 on (Phaseolus vulgaris L.) plants to obtain the best phosphorus treatments. The results were applied in a field experiment during the 2018-2019 season. Single superphosphate (SSP) at 30 and 60 kg P2O5 fed-1 and NCaP at 10%, 20% and 30% from the recommended dose were applied to the soil. Foliar application involved both monoammonium phosphate (MAP) at one rate of 2.5 g L-1 and NCaP at 5% and 10% from the MAP rate. The results of all experiments showed that NCaP significantly increased the shoot and root dry weights, the nutrient content in the shoot and root, the yield components, the nutrient concentration and crude protein percentage in pods of the snap bean plants compared with traditional P. The greatest increase was obtained from a 20% NCaP soil application in combination with a 5% NCaP foliar application. The present study recommends using NCaP as an alternative source of P to mitigate the negative effects of traditional sources.

Sodium titanate nanotubes for efficient transesterification of oils into biodiesel.

In this work, sodium titanate nanotubes were prepared by a hydrothermal method for 23 h at 160 °C and characterized by high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) methods, and Fourier transform infrared (FT-IR) spectroscopy. The obtained nanotubes were used as catalysts in the transesterification of pure and cooked oils under different experimental conditions (molar ratio, temperature, catalyst weight, and time). The catalyst showed high efficiency depending on the chosen conditions. The biodiesel yield was found to be 95.9% at 80 °C for 2 h. The catalyst also showed high activity for cooked oil conversion, with yields of 96.0, 96.0, and 93.58% for the first, second, and third uses of oil, respectively. The methanol was recycled and used in another transesterification experiment, and the biodiesel yield reached 91%. Density functional theory, Monte Carlo simulation, and molecular dynamics simulation were employed to clearly understand the transesterification mechanism. The transesterification reaction is represented by a pseudo-first-order kinetics model. Graphical Abstract .