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采用具有丰富分级多孔结构的豆芽为模板,经水热法合成仿生形态的纳米CeO2/石墨烯催化剂。使用XRD、拉曼光谱(Raman)、TEM、场发射扫描电子显微镜(FESEM)、紫外-可见漫反射光谱(UV-Vis/DRS)、氮气吸附-脱附仪和光解水制氢系统等分析表征手段对CeO2/石墨烯催化剂的结构、形貌及光催化性能进行分析。结果表明,所制备的CeO2/石墨烯光催化剂不仅继承了豆芽模板高孔隙率和大比表面积的特点,而且保持了豆芽的形态和微观特征。该催化剂是由约5.6 nm CeO2纳米晶与具有生物形态的仿生石墨烯片层结构结合而成。制得的CeO2/石墨烯复合材料内部存在大量由CeO2/石墨烯催化剂纳米颗粒堆积而成的纳米孔,其孔径集中分布于15~45 nm左右,这种微观结构使CeO2/石墨烯催化剂具有超大的比表面积,提高了催化剂对光生电子空穴对的捕获能力。由紫外-可见漫反射吸收光谱可知,CeO2/石墨烯复合材料的可见光利用率显著增强,光解水制氢效率6 h后可达到671μmol(h·g)-1,远高于标样CeO2的51.67μmol(h·g)-1。
The nanostructured CeO2 / graphene catalyst was synthesized by hydrothermal method using bean sprouts with rich hierarchical porous structure as template. The samples were characterized by XRD, Raman spectroscopy, TEM, field emission scanning electron microscopy (FESEM), UV-Vis / DRS, nitrogen adsorption-desorption spectrometry Means for the CeO2 / graphene catalyst structure, morphology and photocatalytic properties were analyzed. The results showed that the CeO2 / graphene photocatalyst not only inherited the characteristics of high porosity and large specific surface area of bean sprouts, but also maintained the morphology and microscopic characteristics of bean sprouts. The catalyst is composed of about 5.6 nm CeO2 nanocrystal and biomorphic biomimetic graphene sheet structure combined. The prepared CeO2 / graphene composite has a large number of nano-pores formed by stacking nano-particles of CeO2 / graphene catalyst, and the pore diameters are concentrated around 15-45 nm. This microstructure enables the CeO2 / graphene catalyst to have an extremely large The specific surface area of the catalyst increases the capture efficiency of the photo-generated electron-hole pairs. The visible light utilization efficiency of CeO2 / graphene composites was significantly enhanced by UV-Vis diffuse reflectance spectroscopy. The efficiency of hydrogen production by photolysis water can reach 671μmol (h · g) -1 after 6 h, which is much higher than that of CeO2 / 51.67 μmol (h · g) -1.