【作者】 秦妍； 李英；

【Author】 Yan Qin;Ying li;Key Lab for Colloid and Interface Chemistry of State Education Ministry,Shandong University;

【机构】 山东大学化学与化工学院胶体与界面教育部重点实验室；

【摘要】 随着工业技术的发展,由有机化合物和有毒金属离子造成的环境污染日益严重。非均相光催化剂可利用光能将有机污染物转换为CO2和H2O,在有机污染治理中具有重要的应用前景。在众多应用于光催化领域的半导体材料中,ZnO由于制备成本较低、环境友好、具有高的电子迁移率和催化性能受到了广泛关注,但因存在电子—空穴易结合的问题使催化性能下降。与高导电性的助催化剂复合可提高其电子-空穴迁移速率,进而提高其光催化性能和光稳定性是十分有价值的途径。本文以价廉的石墨粉为原料制备出片层尺寸和厚度分别在10μm和1-2nm左右的GO片层,然后利用预交联-浸渍-原位生长还原的方法制备了具有高催化活性的G/ZnO复合气凝胶。研究结果表明,该气凝胶对亚甲基蓝、甲基橙和罗丹明B等染料均具有良好的光催化活性,其降解速率符合拟一阶动力学方程,速率常数最高可达0.3231min-1,远大于以往文献报道值。经过五次循环降解实验,该复合材料的性能没有发生明显下降,说明石墨烯与ZnO的复合大大提高了其光稳定性。机理探究表明,在催化降解过程中起作用的活性物质主要是单线态氧。该复合材料大的比表面积和孔道结构可以促进染料分子的快速吸附和光催化反应的进行;同时G导电性能的恢复提高了电子-空穴的迁移速率;Zn O纳米粒子与石墨烯片层均匀键合阻止了团聚现象的发生,进一步提高了催化活性。本文报道的G/ZnO复合气凝胶的制备方法具有低成本、低密度、高催化活性等优点,制得的复合材料在水和土壤有机污染治理方面具有广阔的应用前景。更多还原

【Abstract】 With the development of industrial technology, enviromental pollution caused by organic compounds and toxic metal ions is becoming more and more serious. Heterogeneous photocatalyst can convert organic pollutants into CO2 and H2 O by light energy, which plays an important role in environmental pollution control. In many semiconductor materials applied in photocatalysis, ZnO has been widely studied due to its low cost, environmental friendliness, high electron mobility and catalytic performance, but at the same time, the easy combination of electron-hole reduced the catalytic performance. Therefore, it is necessary to combine with the high conductivity cocatalyst to improve the electron-hole migration rate, so as to improve its photocatalytic performance and photostability. In this paper, GO sheets of about 10 μm and 1-2 nm in size and thickness were prepared from cheap graphite powder. And G/ZnO composite aerogel with high catalytic activity was prepared by pre-crosslinking, impregnation and in situ growth reductiom.It was found that the aerogel had a good photocatalytic activity for different dyes, such as methylene blue, methyl orange and rhodamine B, and its degradation rate was fitted with the pseudo-first-order kinetic equation, the rate constant was 0.1975 min-1, far higher than the value reported in previous literature. After five cyclics of degradation experiments, the properties of the composites did not decrease significantly, which indicated that the photostability of the composites was greatly improved by the combination of graphene and zinc oxide. It is found that singlet oxygen is the main active substance in catalytic degradation. The excellent photocatalytic performance is attributed to its large specific surface area and pore structure, which promote the fast adsorption and photocatalytic reaction of dye molecules. At the same time, the recovery of graphene conductivity improve the electron-hole migration rate.ZnO nanoparticles with small size were uniformly bonded to graphene sheets without obvious agglomeration, which further enhanced the catalytic activity. The G/ZnO composites reported in this paper has the advantages of low cost, low density and high catalytic activity, which has broad application in the treatment of water and soil organic pollution. This indicates that G/ZnO composite aerogel prepared by this method has a broad application prospect in water pollution treatment.更多还原