Sao Paulo State University (Unesp), Institute of Science and Technology, Sorocaba, 511 Três de Março Avenue, Sorocaba, SP, 18087-180, Brazil.
Federal Institute of Education, Science and Technology of São Paulo (IFSP), Campus São Roque, 2100 Major Quintino de Lima Highway, São Roque, SP, 18145-090, Brazil.
Environ Sci Pollut Res Int. 2021 Jun;28(21):27147-27161. doi: 10.1007/s11356-021-12571-z. Epub 2021 Jan 27.
This study reports the preparation of TiO and CeO doped with different quantities of terbium and discusses the influence of this dopant on the photocatalytic activity of the semiconductors, with respect to the degradation of methylene blue, under ultraviolet and solar radiations. The oxides obtained were characterized by X-ray diffraction, infrared vibrational spectroscopy, diffuse reflectance spectroscopy, scanning electron microscopy, and dispersive energy spectroscopy. The results indicate that the presence of the dopant in TiO favored the formation of the anatase crystalline phase to the detriment of rutile, increased the band gap energy, and decreased the size of the nanoparticles. Doping CeO with Tb resulted in a fluorite-type crystalline structure, reduced band gap, and smaller particle size. The photocatalytic activity decreases as the concentration of terbium increases regardless of the radiation source and nature of the oxide. Furthermore, a better performance was observed for all semiconductors excited by solar radiation in comparison to ultraviolet light. The samples of pure TiO and TiO doped with 0.5 and 1% terbium showed total removal of the dye after less than 120 min of reaction, while the samples of pure CeO and CeO doped with 0.5% terbium showed approximately 80% and 57% of dye removal after 120 min, suggesting that these materials can be promising for the treatment of industrial effluents.
本研究报告了不同数量的铽掺杂 TiO 和 CeO 的制备，并讨论了这种掺杂剂对半导体光催化活性的影响，即在紫外线和太阳辐射下，亚甲基蓝的降解。所得氧化物通过 X 射线衍射、红外振动光谱、漫反射光谱、扫描电子显微镜和能量色散光谱进行了表征。结果表明，掺杂剂在 TiO 中的存在有利于锐钛矿晶相的形成而不利于金红石相的形成，增加了带隙能，并减小了纳米颗粒的尺寸。CeO 掺杂 Tb 导致萤石型晶体结构，减小了带隙，并减小了颗粒尺寸。无论辐射源和氧化物的性质如何，随着铽浓度的增加，光催化活性都会降低。此外，与紫外线相比，所有半导体在太阳辐射激发下的性能都更好。在不到 120 分钟的反应时间内，纯 TiO 和掺杂 0.5%和 1%铽的 TiO 样品完全去除了染料，而纯 CeO 和掺杂 0.5%铽的 CeO 样品在 120 分钟后去除了约 80%和 57%的染料，表明这些材料可用于处理工业废水。
