Activity Of ZnO Powder Research Articles

Photocatalytic activity of ion-doped ZnO powders

Na, Mg and Al-doped ZnO nano-powders were prepared by the sol-gel method. Acetate of zinc and nitrate salts of Na, Mg and Al were mixed with solution of ethanolamine and 2-methoxyethanol. The xerogel was calcinated at 973 K for 1 h in the air to eliminate organic matter and form powders. The structural, the grain size of doped ZnO and photocatalvtic activity of the powders were investigated. The samples crystal structure were analyzed by XRD and photocatalytic activity were carried out in a UV-visible spectrophotometer. Photocatalytic degradation of the methyl orange solution under the light of wavelength of 254 nm was performed to investigate the photocatalytic activity of doped ZnO powders. The results showed that dopant can greatly improve the photocatalytic activity of ZnO powders. The enhancement of photocatalytic activity of doped ZnO powers is mainly due to their smaller particle size and capability for reducing the electron hole pair recombination.

Effect of Grinding on the Photocatalytic Activity of Commercial ZnO Powder

The effect of grinding on the photocatalytic activity of commercial ZnO powder was explored using methyl orange as a model pollutant and the corresponding mechanism was discussed tentatively. The results indicate that the photocatalytic activity of the ZnO powder grinded decreases obviously in comprison with that of the ZnO powder untreated. This phoenomenon might be ascribed to the decrease of surface defects of ZnO induced by grinding, suggesting that the further treatment leading to the change of surface states of ZnO powder as a photocatalyst ought to be avoided.

Study of the Photocatalytic Activity of Na and Al-doped ZnO Powders

Na and Al-doped ZnO nano-powders were prepared by the sol-gel method. The XRD results indicated that all samples revealed a wurtzite-type hexagonal crystalline structure and the grain size of Al-doped ZnO decreases with increasing Al doping. The grain size of Na-doped ZnO is about 50 nm. Photocatalytic degradation of the methyl orange solution under the light of wavelength of 254 nm was performed to investigate the photocatalytic activity of Na, Al-doped ZnO powders. The results showed that Al dopant can greatly improve the photocatalytic activity of ZnO powder. The enhancement of photocatalytic activity of doped ZnO powers is mainly due to their smaller particle size and capability for reducing the electron hole pair recombination.

Effect of Mechanical Milling on Structure, Morphology and Electrochemical Performance of Zinc Oxide Powders

ZnO powders were treated by mechanical milling. The structure and morphology of ZnO powders milled for different periods were characterized by XRD and SEM. The discharge behavior and cycle life of ZnO electrodes in Zn/Ni batteries were studied by galvanostatic charge and discharge tests. The incorporation of cycle voltammetry was adopted to investigate charge and discharge mechanisms of ZnO electrodes. The results showed that the grain size of the powders decreased from 135.6 nm to 17.9 nm while the lattice strain increased from 0.06% to 0.57% during milling, which could be attributed to the formation and movement of dislocations. The electrochemical reaction activity of ZnO powders was improved by mechanical milling, resulting in an increase of discharge capacity. ZnO powders milled for 100 h shows a high discharge capacity of 300.6 mAh/g, which is 50 mAh/g higher than that of the unmilled ZnO powders.