Y.Z. Yang

Preparation and properties of TiB2 nanoparticle reinforced copper matrix composites by in situ processing

Abstract A copper matrix composite reinforced by in situ TiB 2 nanoparticle was prepared by reactions of B 2 O 3 , carbon and titanium in copper–titanium melt. The microstructure and mechanical and electrical properties of the as-drawn in situ composite were investigated. The results showed that the in situ-formed TiB 2 particles, which had a size of about 50 nm, exhibited a homogenous dispersion in the copper matrix. Due to their reinforcement, the tensile strength and hardness of the in situ Cu–TiB 2 composite significantly improved. Moreover, the as-drawn in situ composite had a high electrical conductivity.

Hydrothermal synthesis of hydrangea-like F-doped titania microspheres for the photocatalytic degradation of carbamazepine under UV and visible light irradiation

Hydrangea-like F-doped TiO2 microspheres have been synthesized on a large scale by a simple hydrothermal process using potassium titanium oxalate as the titanium source, ammonium fluoride and hydrogen peroxide as the etchant. The photocatalytic activities were evaluated using carbamazepine as the target organic molecule under UV and visible light irradiation. Structural characterization indicates that the hydrangea-like TiO2 microspheres, with an average diameter of 2.80 µm, are composed of numerous anatase TiO2 petals. Moreover, it is found that both the NH4F and H2O2 dosages have important effects on the formation of the hydrangea-like structures. In addition, photocatalytic experiments show that the hydrangea-like TiO2 microspheres calcined at 500°C exhibit high photocatalytic efficiency under both UV and visible light irradiation. The enhanced photocatalytic activity can be attributed to the successful fluorine doping, good crystallinity, and the unique nanostructures.

Effect of LiCoO2 coating on the electrochemical performance of LiMn0.9Co0.1O2 cathode materials for Li-ion batteries

Layer-structured LiMn0.9Co0.1O2 cathode materials for lithium-ion batteries were synthesized by ion exchange method. A layer of LiCoO2 was coated on the surface of the as-prepared LiMn0.9Co0.1O2 powder via melting impregnation method. The structure and morphology of the powders were characterized by means of x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of the cathode materials were investigated using a half-cell in a potential range of 2.0–4.5 V versus Li/Li+. The LiMn0.9Co0.1O2 coated with 7 wt.% of LiCoO2 exhibited good electrochemical properties with a discharge capacity of 158 mAh g−1 and 89% charge retention after 50 cycles.