TiO₂ is a photocatalyst widely used for the degradation of organic compounds in aqueous media; however, it presents some difficulties for application on larger scales. The biggest limitations are its bandgap value of 3.2 eV which corresponds to the UV range of the spectrum and its difficult removal from the reaction medium after the reaction. An alternative to enhance the photocatalytic activity of TiO₂ consists in design heterojunctions with semiconductors that are active under visible light irradiation. Some reports have described the magnetic property and synthesis procedures based on inexpensive and abundant raw material. In this work, we synthesized photocatalysts based on γ-Fe₂O₃impregnated with different levels of TiO₂. This may contribute to improving the wide application of TiO₂ in water, since γ-Fe₂O₃ has magnetic features that facilitate the removal of the catalyst after the reaction run. The materials were characterized by X-ray diffraction, analysis of adsorption/desorption of N₂, reflectance diffuse, and ⁵⁷Fe Mössbauer spectroscopy. The photocatalytic activity of the materials was tested for removing rhodamine under visible or visible light in the presence of H₂O₂. From the X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy data, it was observed the formation of γ-Fe₂O₃ phase with small particle. Without visible light, only 45% of RhB was adsorbed, and with the light on, there is no increase in removal after 60 min. However, after adding H₂O₂, the photocatalytic activity of material was significantly improved, reaching 80% of dye removal. Tests using scavengers of reactive species revealed that ⁻O₂ and ․OH are the main species in this system. Moreover, the H₂O₂ retards the electron-hole recombination, thus increasing its photocatalytic activity. The ESI-MS analysis revealed that in 15 min of reaction, deethylation (m/z = 415, 388), deamination (m/z = 301 and 279), and rhodamine B severe oxidation products (m/z < 250) were present in solution, and TOC analysis confirms the mineralization of the rhodamine.

TiO ₂是一种光催化剂，广泛用于降解水性介质中的有机化合物。但是，在较大规模的应用中存在一些困难。最大的限制是其带隙值3.2 eV，它对应于光谱的紫外线范围，并且在反应后难以从反应介质中除去。增强TiO ₂的光催化活性的另一种方法是设计与半导体在可见光下具有活性的异质结。一些报道已经描述了基于廉价和丰富的原料的磁性和合成方法。在这项工作中，我们合成了基于光催化剂了γ-Fe ₂ ö ₃具有不同水平的TiO浸渍₂。这可有助于改善TiO 2的广泛应用₂在水中，由于γ-的Fe ₂ ö ₃具有促进反应运行后除去催化剂的磁性特征。通过X射线衍射，N ₂吸附/解吸分析，反射扩散和⁵⁷ FeMössbauer光谱对材料进行表征。测试了在H ₂ O ₂存在下在可见光或可见光下材料的光催化活性以去除若丹明。从X射线衍射及⁵⁷的Fe穆斯堡尔谱数据，观察到的形成了γ-Fe ₂ ö ₃小颗粒相。没有可见光，只有45％的RhB被吸附，并且在光照下，60分钟后去除率没有增加。但是，加入H ₂ O _2后，材料的光催化活性显着提高，达到了80％的染料去除率。使用反应性物种的清除剂试验显示，^- Ò ₂和·OH是该系统中的主要种类。此外，H ₂ O ₂阻碍了电子-空穴的重组，从而增加了其光催化活性。ESI-MS分析表明，在15分钟的反应中，会出现脱乙基（m / z = 415、388），脱氨基（m / z = 301和279）和罗丹明B严重氧化产物（m / z <250）。在溶液中，TOC分析证实了若丹明的矿化作用。