直接沉淀法制备纳米氧化锌及其光催化性能研究

Research on the Preparation of Nanometer Zinc Oxide by Direct Precipitation Method and Its Photocatalytic Properties

以直接沉淀法制备纳米ZnO,并利用其对亚甲基蓝溶液进行光催化降解反应。分别研究了Na_2CO_3浓度和前驱物焙烧温度对纳米ZnO光催化性能的影响。结果表明:在ZnSO_4和Na_2CO_3溶液浓度分别为0.25 mol/L和1.0 mol/L、滴加速度6.4 mL/min、焙烧温度500℃的条件下,制备出的纳米ZnO对亚甲基蓝的光催化效果最佳。借助于FTIR和TGA-DSC对前驱物的组成进行分析,得出其组成为ZnCO_3和Zn(OH)_2的混合物(碱式碳酸锌);XRD证明了制得的ZnO纳米光催化材料的晶型为六方晶系纤锌矿,而且结晶度较高;从SEM图像中,可观察到纳米级的催化剂颗粒,以及它们之间严重的团聚现象;用激光粒度仪测水溶液中纳米材料粒径分布,发现其主要以微米的形式存在。

Nanometer zinc oxide was prepared by direct precipitation method and its photocatalytic properties were studied with methylene blue degradation.The effect of the preparation conditions such as the concentration of Na2CO3 and ZnSO4 solutions,addition rate of the solutions and the calcination temperature on the photocatalytic performance of the nanometer ZnO were investigated.The results show that the photocatalytic degradation rate of methylene blue catalyzed by the nanometer ZnO prepared with 0.25 mol/L ZnSO4 solution,1.0 mol/L Na2CO3 solution,addition rate of 6.4 mL/min and 500℃calcination was the highest.The FTIR and TGA-DSC analysis demonstrated that the precursor was a mixture of zinc carbonate and zinc hydroxide.The XRD patters indicated that the nanometer ZnO had hexagonal wurtzite structure with high crystallinity.Aggregates of nanometer particles were clearly visible in scanning electron microscope(SEM).Further,the measurement of the particles distribution clearly showed that the nanometer ZnO dispersed in micron size in aqueous solution.