Polyaniline/nano titanium dioxide/graphene nanoplatelet (PANI/TiO2/G) composite was synthesized by mechanochemical route. The structure and morphology of the composite were characterized by Fourier transform infrared spectra, ultraviolet-visible absorption spectra, x-ray diffraction and transmission electron microscopy. The electrochemical performances of the composite were investigated by galvanostatic charge-discharge, cyclic voltammetry, cycling stability and electrochemical impedance spectroscopy. The structure and properties of PANI/TiO2/G composite were compared with that of polyaniline/ graphene nanoplatelet (PANI/G) composite prepared under the same polymerization conditions. After comparative analysis with PANI/G, the effects of the nano titanium dioxide (TiO2) on the structural and physicochemical properties of the PANI/G have been discussed in depth. The comparison suggested that the PANI/TiO2/G composite has higher oxidation degree and lower crystallinity than PANI/G due to the addition of nano-TiO2. Morphology studies showed that PANI and nano-TiO2 particles were both observed on the bent and flat surfaces of graphene nanoplatelet in the PANI/TiO2/G composite. The electrochemical tests showed that the PANI/TiO2/G composite displayed a higher electrochemical activity with specific capacitance of 516 F/g (3 mA/cm2) and better cycle stability than PANI/G.

Nanoerythrocyte-shaped ytterbium orthovanadate (YbVO4) with substantially uniform size have been successfully synthesized by a simple and facile trisodium citrate-assisted hydrothermal method. The erythrocyte-shaped YbVO4 nanocrystals with self-assembled spherical and biconcave structure have a diameter of ∼500 nm, which were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy and photoluminescence. The luminescent properties of erbium ion-doped ytterbium orthovanadate nanocrystals with different morphologies by different complexing agents were different in the relative intensity under identical measurement conditions, which exhibited the interesting morphology-dependent optical properties. The different energy transfer mechanisms and photoluminescence intensities might be the result of the greatly reduced defect centers.

Uniform ytterbium ion and erbium ion codoped gadolinium oxyfluoride (GdOF: Yb3+, Er3+) hollow nanospheres of 100-nm diameter were synthesized via the nanoscale Kirkendall approach, using colloidal nanospheres of ytterbium ion and erbium ion codoped gadolinium hydroxide [Gd(OH)3: Yb3+, Er3+] as sacrificial templates and titanium tetrafluoride as fluorine source under hydrothermal condition. The shell thickness of the as-synthesized GdOF: Yb3+, Er3+ hollow nanospheres can be facilely tuned from 31 to 13 nm by controlling reaction temperature and reaction time. The upconversion emission color could be adjusted from red to yellow to green when the host lattices variedfrom gadolinium (III) oxide to gadolinium oxyfluoride to gadolinium fluoride. Furthermore, the formation mechanism of the hollow GdOF: Yb3+, Er3+ nanospheres was found to depend on the fluorine source.

A potential order-of-magnitude increase in Hall-Petch (H-P)-based strength level for nanoscale grain-size structures is an important enabler of electronic thin film material design applications. Dislocation pileups of smaller lengths in such thin film materials are blocked in a screw orientation at the through-thickness grain boundaries of relatively larger grains. For fully nanopolycrystalline materials, both strength and strain rate sensitivity measurements exhibit complementary H-P reciprocal square root of grain size dependencies. An additional increase in strength level is predicted for transition from a pileup to a single dislocation loop expanding against the grain boundary obstacle. In opposition, disordered grain boundaries are responsible for a reduced H-P stress intensity, kε. And at the limiting high stresses reached at lower-limiting nanoscale grain sizes, reversed H-P dependences are obtained both for the strength and strain rate sensitivity.

Unique cocoon- and rod-shaped alpha-phase ferric oxide, hematite (α-Fe2O3) is prepared by a simple, scalable and surfactant-free chimie douce synthesis. The structure and morphology is confirmed by x-ray diffraction, field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The electrochemical properties of α-Fe2O3 anodes are investigated using cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The mesoporous α-Fe2O3 exhibited an initial discharge capacity >1741 mAh/g with excellent cycling performance and rate capabilities. The solvent used for the preparation of α-Fe2O3 plays a key role in determining the morphology of the materials, which greatly influenced its electrochemical properties.

Zinc oxide (ZnO) nanomaterial is a superior material for photoanode. However, the different reaction concentrations, growth time and reaction vessel have influences on the structure and morphology of ZnO, and and ultimately have a bearing on the performance of solar cells. In this article, we used the hydrothermal method for the preparation of ZnO nanostructure. For avoiding direct contact of electrolyte with fluorine-doped tin oxide conducting glass, and decrease the recombination probabilities, we used titanium tetrachloride pretreatment. For obtaining flower-like ZnO nanostructure that was composed of smaller diameter ZnO nanorods, we fabricated a smaller-particle seed layer prior to growing ZnO nanostructure. For the sake of getting the best performances of solar cells, we examined the various effects of different deposition cycles on the performance of the solar cells. We discovered that when the deposition cycles increased, short-circuit current density, open-circuit voltage, fill factor and conversion efficiency all increased. But when the deposition exceeded 9 cycles, the values of all the parameters decreased. When the deposition cycle is 9, the conversion efficiency is 1.156%.

The success of polyolefins is governed to a large extent by the development of robust and versatile catalysts offering excellent morphology control. This review highlights the major evolution steps made in the polyolefin catalyst systems in terms of productivity and possibilities to control the molecular architecture of both polypropylene and polyethylene. Starting from the initial TiCl3-types, the continuous improvement of the Ziegler-Natta catalysts in terms of performance and cost is the major factor behind their wide market penetration. On the other hand, metallocene and the other “single-site” catalysts enable an unprecedented fine-tuning of chain microstructure by ligand design. In this article, special emphasis is placed on the influence of catalyst type on polymer structure characteristics such as molecular weight distribution, stereoregularity, and comonomer distribution and, ultimately, on the end-use properties of polyolefins. It is the excellent balance among price, performance, and processability that will further strengthen the position of polyolefins as a dominant class of materials in the polymer industry.

The future of polyolefin-based materials and the opportunities for further research and development in Ziegler-Natta catalysis are discussed. Thorough control of polymer microstructure and architecture ensured by modern olefin polymerization catalysts and processes warrants further progress in fundamental and applied research for many years to come.

Two new organic dyes, WS-2.1 and WS-2.2—derivatives of the known dye WS-2—are computationally designed using a recently developed approach with a broad absorption peak at around 775 nm in acetonitrile for WS-2.2 versus 610 nm for WS-2. The red shift includes a significant contribution due to vibrations and is not reproduced by standard computational methods. The oxidation and reduction potentials of the dye render it well suited for use in dye-sensitized solar cells.