Obtaining of Carbon Nanotubes in Reactor with Fluidized Bed of Catalyst

The researching activity related to CNTs has grown most significantly over the past 10 years. Since 2006, world capacities of production of CNTs have increased 10-fold. The annual number of scientific publications on CNT and issued patents continues to grow [1]. Carbon nanotubes are used in many areas, such as energy, biotechnology, microelectronics, textiles, etc...

Low-dimensional non-toxic A3Bi2X9 compounds synthesized by a dry mechanochemical route with tunable visible photoluminescence at room temperature

We have synthesized fifteen inorganic and hybrid organic-inorganic non-toxic A3Bi2X9 compounds (A = K+, Rb+, Cs+, CH3NH3+ and HC(NH2)2+; X = I−, Br−, Cl−) through dry mechanochemistry. We demonstrate that this synthetic method is very well suited to prepare compounds from poorly soluble precursors, allowing thus the preparation of so far unreported compounds. X-ray diffraction analysis demonstrates the high crystallinity of the so-formed ternary bismuth halides. Furthermore, we show that, through substitution of the A-cation and X-anion, the bandgap of these compounds can be tuned to absorb throughout the whole visible spectrum. As-prepared powders of Cs3Bi2Br9 and Cs3Bi2I9 without any passivating agents show room-temperature photoluminescence covering the visible spectrum from 450 nm to 800 nm, making them especially promising for white-light emission

Fast Polymeric Functionalization Approach for the Covalent Coating of MoS2 Layers

We present the covalent coating of chemically exfoliated molybdenum disulfide (MoS2) based on the polymerization of functional acryl molecules. The method relies on the efficient diazonium anchoring reaction to provoke the in situ radical polymerization and covalent adhesion of functional coatings. In particular, we successfully implement hydrophobicity on the exfoliated MoS2 in a direct, fast, and quantitative synthetic approach. The covalent functionalization is proved by multiple techniques including X-ray photoelectron spectroscopy and TGA-MS. This approach represents a simple and general protocol to reach dense and homogeneous functional coatings on 2D materials

Морфологические и физико-химические свойства наноструктурированной целлюлозы, полученной химическим и биологическим способами

The authors obtained samples of chemically pure, crystalline, microand nanostructured cellulose of various modifications using two approaches – biological and chemical. They studied these cellulose samples via scanning electron microscopy (SEM), thermogravimetric analysis, and infrared (IR) spectroscopy. To prepare cellulose microcrystals, they used the mild acid treatment method based on glycerolacid mixtures for treating cotton fibers. They showed that the chemical processing of cotton fiber ensured its dispersion with generation of microcrystals surrounded by a partially preserved amorphous shell. The authors produced bacterial cellulose (BC) films using the Komagataeibacter xylinus C3 strain in surface cultivation conditions. With a view of obtaining higher-quality SEM images, they applied chemical fixation of lipids and proteins with critical drying to fix the process of nanofiber synthesis by bacterial cells. The two-step fixation method helped find the fibrillar structure of a cellulose film, while the morphology of bacterial cells was not deformed. The authors made a comparative analysis of the IR spectroscopy results between chemically synthesized cellulose microcrystals and BC. The obtained cellulose samples do not contain lignin and hemicellulose, both samples are highly crystalline. The BC has an ordered structure, higher crystallinity and gets carbonized when exposed to air pyrolysis. A thermogravimetric analysis of the samples shows the absence of thermally stable impurities. Both cellulose samples of biological and chemical origin are thermally stable, and the initial decomposition temperature is high enough for cellulose materials. These results show that the authors have managed to create nanocellulose materials that might be potentially applied in various industries, such as pharmaceuticals, functional composites, engineering, etc

Obtaining of Carbon Nanotubes in Reactor with Fluidized Bed of Catalyst

The researching activity related to CNTs has grown most significantly over the past 10 years. Since 2006, world capacities of production of CNTs have increased 10-fold. The annual number of scientific publications on CNT and issued patents continues to grow [1]. Carbon nanotubes are used in many areas, such as energy, biotechnology, microelectronics, textiles, etc...

Hybrid Heterostructures of a Spin Crossover Coordination Polymer on MoS2: Elucidating the Role of the 2D Substrate

Controlling the deposition of spin-crossover (SCO) materials constitutes a crucial step for the integration of these bistable molecular systems in electronic devices. Moreover, the influence of functional surfaces, such as 2D materials, can be determinant on the properties of the deposited SCO film. In this work, ultrathin films of the SCO Hofmann-type coordination polymer [Fe(py)2{Pt(CN)4}] (py = pyridine) onto monolayers of 1T and 2H MoS2 polytypes are grown. The resulting hybrid heterostructures are characterized by GIXRD, XAS, XPS, and EXAFS to get information on the structure and the specific interactions generated at the interface, as well as on the spin transition. The use of a layer-by-layer results in SCO/2D heterostructures, with crystalline and well-oriented [Fe(py)2{Pt(CN)4}]. Unlike with conventional Au or SiO2 substrates, no intermediate self-assembled monolayer is required, thanks to the surface S atoms. Furthermore, it is observed that the higher presence of Fe3+ in the 2H heterostructures hinders an effective spin transition for [Fe(py)2{Pt(CN)4}] films thinner than 8 nm. Remarkably, when using 1T MoS2, this transition is preserved in films as thin as 4 nm, due to the reducing character of this metallic substrate. These results highlight the active role that 2D materials play as substrates in hybrid molecular/2D heterostructures