Zn_2GeO_4微米球的一步合成及其光催化制氢活性

One-pot Synthesis and Photocatalytic Hydrogen Evolution Properties of Zn_2GeO_4 Microspheres

采用微波辅助水热法一步合成尺寸约为5μm的Zn_2GeO_4微米球。实验研究了微波水热的反应温度、反应时间、乙酸锌与氧化锗的摩尔比等因素对合成Zn_2GeO_4微米球的影响。采用FE-SEM、TEM、XRD和UV-Vis对合成的微米球进行表征。结果表明,当乙酸锌:氧化锗为6:2,微波辐射温度为170℃,反应时间10 min,尿素用量3.604 g,制备的Zn_2GeO_4微米球具有良好的光催化效果。实验测试Zn_2GeO_4微米球比表面积为13 m^2/g,在紫外光辐射下,在甲醇体系中的光解水产氢速率可达到3.76 mmol/(h·g)。该方法缩短反应时间,增强了光催化活性。

Zn2GeO4 microspheres were synthesized via a one-pot microwave-hydrothermal route, Zn2GeO4particles with the diameter of about 5 μm can be obtained. The synthesis conditions were investigated by a series of controled experiments, revealing that reaction temperature, reaction time and molar ratio of Zn（CHaCOOH）2oH20 to GeO2 were crucial factors controlling formation and morphology of Zn2GeO4 microspheres. The products were characterized by various techniques including field emission scanning electron microscopy （FE-SEM）, X-ray diffraction （XRD）, and ultraviolet-visible diffuse reflectance spectroscopy （UV-Vis）. The results showed that Zn2GeO4 synthesized at condi- tions when n（Zn（CH3COOH）2·H2O ）/n（GeO2）=6：2, 3.604 g urea, microwave heating at 170℃ for 10 min exhibited best photo-degradation activity. With specific surface area being 13 m2/g, the Zn2GeO4 microspheres showed a stable H2 evolution rate of 3.76 mmol/（h·g） under UV light irradiation. Data from this study suggest that this method greatly reduces the reaction time and enhances the photocatalytic activity.