Photocatalytic Degradation of the Malachite Green Dye with Simulated Solar Light Using TiO₂ Modified with Sn and Eu

This work reports on the synthesis of photocatalysts in thin film form of TiO₂ modified with Sn, Eu as well as Sn and Eu simultaneously. The obtained films were characterized by X-Ray Photoelectron Spectroscopy, Raman Spectroscopy and Ultraviolet–Visible Spectroscopy, in order to obtain information on their chemical composition, vibrational features and optical properties respectively. Chemical composition reveal that the tin content was close to 4 at.%, whereas the europium content was approximately 1 at.%. Raman results show that the unmodified material is crystalline TiO₂ in the anatase phase; the Sn addition promotes the formation of the rutile crystalline phase. Europium incorporation as a novel modifier produces TiO₂ in which a mixture of both crystalline phases coexists. Optical measurements reveal that the band gap energy for all samples remains close to 3.4 eV. The photocatalytic activity was evaluated in the degradation reaction of the Malachite Green dye under simulated solar light. The most relevant result is that photocatalysts containing Sn and Eu show higher photocatalytic activity (60% of MG conversion) than the TiO₂ thin film (28% of MG conversion). The main objective of this work was to investigate the changes produced in the resulting material due to Sn and Eu incorporation as well as try to correlate such changes with the corresponding catalytic activity in terms of the Malachite Green dye conversion degree.