Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Jinan 250061, P. R. China.
Phys Chem Chem Phys. 2013 Nov 14;15(42):18627-34. doi: 10.1039/c3cp53178c.
The core-shell structured Fe2O3@TiO2 nanocomposites prepared via a heteroepitaxial growth route using the Fe2O3 spindle as a hard template display improved photocatalytic degradation activity for Rhodamine B dye under visible light irradiation. The ratio of α-Fe2O3 : TiO2 in the α-Fe2O3@TiO2 core-shell nanocomposites can be tuned by etching the α-Fe2O3 core via controlling the concentration of HCl and etching time. An appropriate concentration of the Fe2O3 core could effectively induce a transition of the optical response from the UV to the visible region and decrease the recombination rate of photogenerated electrons and the holes of the core-shell structured catalyst, greatly contributing to the enhancement of visible light response and visible light photocatalytic activity of the Fe2O3@TiO2 catalysts. It is revealed that the optical response and photocatalytic performance of the core-shell α-Fe2O3@TiO2 nanocomposites can be tuned by adjusting the molar ratio of Fe2O3 : TiO2 of the α-Fe2O3@TiO2 nanocomposites. The α-Fe2O3@TiO2 core-shell nanocomposite with an optimal molar ratio of 7% for Fe2O3 : TiO2 exhibits the best photocatalytic performance under visible light irradiation. It is shown that the Fe2O3/TiO2 heterojunction structure is responsible for the efficient visible-light photocatalytic activity. As the concentration of Fe2O3 is high, Fe(3+) ions will act as recombination centres of the photogenerated electrons and holes. The present core-shell Fe2O3@TiO2 nanoparticles displaying enhanced photodegradation activity could find potential applications as photocatalysts for the abatement of various organic pollutants.
采用异质外延生长路线，以 Fe2O3 纺锤为硬模板制备的核壳结构 Fe2O3@TiO2 纳米复合材料显示出在可见光照射下对 Rhodamine B 染料的光催化降解活性得到提高。通过控制 HCl 的浓度和蚀刻时间，可以调整α-Fe2O3@TiO2 核壳纳米复合材料中α-Fe2O3：TiO2 的比例。适当浓度的 Fe2O3 核可以有效地将光响应从紫外区诱导到可见区，并降低核壳结构催化剂中光生电子和空穴的复合率，极大地有助于增强 Fe2O3@TiO2 催化剂的可见光响应和可见光光催化活性。结果表明，通过调整α-Fe2O3@TiO2 纳米复合材料中 Fe2O3：TiO2 的摩尔比，可以调谐核壳α-Fe2O3@TiO2 纳米复合材料的光学响应和光催化性能。当 Fe2O3：TiO2 的摩尔比为 7%时，α-Fe2O3@TiO2 核壳纳米复合材料在可见光照射下表现出最佳的光催化性能。结果表明，Fe2O3/TiO2 异质结结构是其具有高效可见光光催化活性的原因。当 Fe2O3 的浓度较高时，Fe(3+) 离子将充当光生电子和空穴的复合中心。本研究制备的具有增强光降解活性的核壳 Fe2O3@TiO2 纳米颗粒可作为消除各种有机污染物的光催化剂具有潜在应用价值。
