Linhai Yue

Preparation of ZnO particle with novel nut-like morphology by ultrasonic pretreatment and its luminescence property

Novel nut-like zinc oxide crystal has been prepared by a low temperature hydrothermal method with the presence of Cu(2+) ion. It seemed that the ultrasonic pretreatment was the key factor during the preparation process. SEM observations revealed that the as-prepared ZnO crystal exhibited nut shape showing well-defined crystallographic facets. The cross-section of the ZnO crystal was hexagonal of about 800 nm-1 microm in diameter, and the aspect ratio was a little smaller than 1:1. The room temperature photoluminescence behavior of the nut-like zinc oxide crystal was much stronger than the reference samples.

A facile template-free preparation of porous manganese oxides by thermal decomposition method

Porous Manganese oxides with large surface area were prepared by a facile template-free method. Highly crystallized MnCO3 precursors with micron size in high dispersivity were prepared in water first. Thermal treatment was carried out with the obtained composite at different temperatures to produce porous manganese oxides. Thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and N2 adsorption-desorption measurements were applied to characterize the porous manganese oxides. Amorphous MnO2 obtained at 400°C shows a mesoporous structure and has a large specific surface area of 135.1 m2/g. Well crystallized α-Mn2O3 crystal with surface area of 18.51 m2/g macroporous framework was obtained at 600°C.

Synthesis and electrochemical properties of hierarchically porous Fe2O3

Porous Fe2O3 with hierarchical structure was obtained by a two-step template-free synthesis route. Brick-shaped ironic oxalate precursor in micrometer size was first synthesized by a hydrothermal process using (NH4)2SO4 · FeSO4 · 6H2O and K2C2O4 · H2O as raw materials. Then porous iron oxide with well retained brick-shape was obtained by a decomposition process under precisely controlled annealing condition. Morphology and structure of the as-prepared products were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), thermo-gravimetric/differential thermal (TG-DTA) and N2 adsorption-desorption measurements. The electrochemical properties were performed by galvanostatic cell cycling. It revealed that the pore structure can be tailored by the annealing condition and the crystallinity can be tuned by the solvent system. Product with porous structure and low crystallinity exhibited storage capacity of 634 mA h g−1 during the first cycle and efficiency of over 90% after 20 cycles.

Synthesis of BaCO3 with different morphologies using amphiphilic PS-PAA copolymer as medium

Barium carbonate (BaCO3) with multiple morphologies were synthesized using BaCl2 and Na2CO3 in the presence of a copolymer of poly(styrene) (PS) and poly(acrylic acid) (PAA), an amphiphilic copolymer, by a simple solvent reaction route. X-ray powder diffraction and field emission scanning electron microscopy were used to characterize the obtained products. The mole ratio of the PS/PAA was found to play an important role in determining the morphologies of the final products.