中空介孔ZnO@SiO_2微球的制备及其光催化性能

Preparation of hollow mesoporous ZnO@SiO_2 microsphere and its photocatalytic performance

通过三嵌段共聚物P123和PAA两种超分子在乙醇中形成协同模板体系,以溶胶凝胶法成功制备了中空介孔SiO_2微球.通过溶液吸附和高温煅烧的方法将纳米ZnO负载在SiO_2中空球结构中获得ZnO@SiO_2纳米粉体.用X射线衍射仪(XRD)、透射电子显微镜(TEM)、静态氮气吸附仪和紫外-可见漫反射(DRS)对产物的物相组成、微观形貌、比表面积、带隙宽度等进行表征.结果表明:通过负载的方式,样品的比表面积从208 m^2/g提高到253 m^2/g,孔径分布更加均匀,纳米ZnO高度分散在SiO_2载体中,提高了样品的紫外光催化活性.通过在不同乙酸锌浓度下制备的样品对比表明,在40 mmol/L物质量浓度的乙酸锌溶液中所制得的紫外光催化活性最高,在100 min内可以有效降解亚甲基蓝溶液.

Using two kinds of supermolecular, tri-block copolymer P123 and PAA dissolved in ethanol as a synergistic template system, the hollow mesoporous SiO2 microsphere was successfully prepared via sol-gel method. Then the nano ZnO was loaded into the hollow SiO2 structure by means of solution adsorption and high-temperature calcination method to obtain hollow mesoporous ZnO@SiO2 nano-powder. Products were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), static nitrogen adsorption, and UV-vis diffuse reflectance spectroscopy(DRS) to get their phase composition, microscopic morphology, specific surface area and energy gap. The result showed that the specific surface area of the sample increase to 253 m^2/g from 208 m^2/g, the pore size distribution would be more uniform, and the nano-ZnO would be highly dispersed in the SiO 2, enhancing the photocatalytic activity of the sample. Comparing the samples prepared with different zinc acetate concentrations with each other, it was showed that the photocatalytic activity of the samples prepared in 40 mmol/L zinc acetate solution would be the highest, and the methylene blue solution could be effectively degraded within 100 min.