ZnO微棒的制备、表征及光催化活性研究

Stduies on preparation,characterization and photocatalytic activity of ZnO micro rods

以NaOH和Zn(NO_3)_2·6H_2O为原料,采用一种相对温和的水热反应条件,无模板剂及助剂,无需退火,制备出了一种ZnO微棒,考察了水热温度、时间及物料比例对材料的形貌、性能的影响。用X射线衍射(XRD)、场发射扫描电镜(FSEM)、场发射透射电镜(FTEM)及高分辨透射电镜(HRTEM)等手段对产品进行了结构及形貌表征,结果表明产品为结晶良好的六方纤锌矿结构ZnO微棒,温度升高使微棒长大,时间加长使微棒变细变长。紫外-可见(UV-Vis)吸收光谱显示材料对可见光有较大范围弱吸收。以甲基橙为模型污染物考察了材料的光催化活性,测试结果显示,100~oC水热处理4小时的材料具有最好的光催化活性。所制备ZnO微棒对太阳光也有较好响应,即使在阴天不搅拌的情况下,经过4天时间也能将10mg/L甲基橙有效降解,方法安全可靠,节能环保,可望推广到实际废水处理中。

With NaOH and Zn(NO3)2·6 H2O as raw material and without template agent and auxiliaries,a kind of ZnO micro rod was prepared under a relatively mild hydrothermal reaction condition and no annealing.The effect of hydrothermal temperature,time and material proportion on the morphology and properties of the material was investigated.The structure and morphology of the products were characterized by X ray diffraction(XRD),field emission scanning electron microscopy(FSEM),field emission transmission electron microscopy(FTEM)and high-resolution transmission electron microscopy(HRTEM).The results showed that the product was a micro rod with good crystallization of hexagonal wurtzite ZnO.With the temperature raised,the microrods were grow up,and with the time increasing,the microrods became thinner and longer.Ultraviolet visible(UV-Vis)absorption spectra show that the material has a weak absorption in visible range.The photocatalytic activity of the material was investigated with methyl orange as a model pollutant.The test results showed that the best solar photocatalytic activity was obtained by the 100oC hydrothermal treatment for 4 hours.The prepared ZnO micro rod has a good response to the sun light.Even under the condition of no stirring in the cloudy day,the 10 mg·L-1 methyl orange can be effectively degradation after 4 days.The method is safe,reliable,energy saving and environmentally friendly.It is expected to be applied to the practical waste water treatment.