具有分级多孔结构和光催化性质的核-壳纳米球（HP-Fe2O3@TiO2）

摘要

Core-shel photocatalysts of hierarchical porous nanospheres (HP-Fe2O3@TiO2) have been designed and prepared using solvothermal and sol-gel methods. Transmission electron microscopy (TEM) images confirm that the obtained samples have a hierarchical porous structure, which results from both the macroporous structure of the core (Fe2O3) and the mesoporous structure of the shel (TiO2). X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption isotherms were employed to characterize the structure and properties of HP-Fe2O3@TiO2 nanospheres. We investigated the photocatalytic degradation (in the presence of H2O2) of methylene blue (MB) irradiated under visible and ultraviolet light. The observed photocatalytic performance of HP-Fe2O3@TiO2 nanospheres is attributed to the synergetic effects of the core-shel structure, which indicates that the TiO2 shel enhances the photocatalytic performance of α-Fe2O3. HP-Fe2O3@TiO2 (1 mL Ti(OC4H9)4 (TBT)) possesses the highest photodegradation reaction constant among al samples under visible light irradiation. Moreover, HP-Fe2O3@TiO2 (4 mL TBT) has an optimal monodisperse morphology and achieves high photocatalytic activity under ultraviolet light irradiation.%　　通过溶剂热和溶胶-凝胶涂层法，设计并制备了具有分级多孔结构和光催化性质的核-壳纳米球(HP-Fe2O3@TiO2)。透射电子显微镜(TEM)照片证明所得HP-Fe2O3@TiO2样品具备分级多孔结构，这是因为HP-Fe2O3@TiO2的内核(Fe2O3)具有大孔空隙，同时外壳(TiO2)具有介孔空隙。此外，通过X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线光电子能谱(XPS)以及氮气吸附-脱附曲线深入研究了HP-Fe2O3@TiO2的结构及其性质。分别在可见及紫外光照下，研究了样品在H2O2体系下的光催化降解亚甲基蓝(MB)的性质。所观察到的HP-Fe2O3@TiO2纳米球的光催化性能，可归因于核-壳结构的协同作用，这进一步表明， TiO2外壳对α-Fe2O3的光催化活性有重要影响作用。在可见光照射下， HP-Fe2O3@TiO2(1 mL Ti(OC4H9)4(TBT))具有较优异的光催化活性。同时， HP-Fe2O3@TiO2(4 mL TBT)具备优异的单分散形貌，并在紫外光照射下，表现出最优的光催化活性。