Fe[sub.3]O[sub.4]-TiO[sub.2] Thin Films in Solar Photocatalytic Processes

• Published in: Materials Vol. 15; no. 19
• Main Authors: Aguinaco, Almudena, Mánuel, José M, Blanco, Eduardo, Domínguez, Manuel, Litrán, Rocío, Delgado, Juan J, Ramírez-del-Solar, Milagrosa
• Format: Journal Article
• Language: English
• Published: MDPI AG 01-09-2022
• Subjects: Dielectric films; Magnetic fields; Thin films
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15196718

The optical properties of 5wt% Fe[sub.3]O[sub.4]-TiO[sub.2] thin films were evaluated in detail with the aim of proposing a mechanism for solar photocatalytic processes and highlighting the advantages over the use of bare TiO[sub.2]. The results showed that the incorporation of 5wt% Fe[sub.3]O[sub.4] enhanced the optical properties by a redshift to a wavelength in the visible range, reducing the anatase/rutile band gap energy from 3.2 eV to 2.8 eV. Photoluminescence studies reveal a superior separation efficiency of photoexcited electron-hole pairs when Fe[sub.3]O[sub.4] nanoparticles (NPs) are present in the photocatalyst. X-ray photoelectron spectroscopy spectra confirm the presence of Fe[sub.3]O[sub.4] and existence of a chemical bonding between TiO[sub.2] and Fe[sub.3]O[sub.4] NPs. Moreover, in this study, a mechanism of solar photocatalytic processes involving Fe[sub.3]O[sub.4]-TiO[sub.2] thin films is proposed and it is supported by experimental results. Finally, solar photocatalytic experiments were carried out, indicating that the effectiveness for the removal of the selected pharmaceutical is considerably improved when the composite material is used as catalyst. Furthermore, it was demonstrated that the photocatalytic activity of the prepared Fe[sub.3]O[sub.4]-TiO[sub.2] thin films depends on their thickness, achieving the highest pharmaceutical removal yields using the 2 µm thick sample. The stability and reusability of the catalyst was confirmed studying the photocatalytic activity over three cycles.