Yifan Zheng

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.