Fe3O4-TiO2 Thin Films in Solar Photocatalytic Processes

Abstract

The optical properties of 5wt% Fe3O4-TiO2 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 TiO2. The results showed that the incorporation of 5wt% Fe3O4 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 Fe3O4 nanoparticles (NPs) are present in the photocatalyst. X-ray photoelectron spectroscopy spectra confirm the presence of Fe3O4 and existence of a chemical bonding between TiO2 and Fe3O4 NPs. Moreover, in this study, a mechanism of solar photocatalytic processes involving Fe3O4-TiO2 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 Fe3O4-TiO2 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.

Photocatalytic CO2 reduction to methanol integrated with the oxidative coupling of thiols for S–X (X = S, C) bond formation over an Fe3O4/BiVO4 composite

“…X for BiVO 4 and Fe 3 O 4 is 6.035 eV and 5.77 eV, respectively. 47,48 E c = 4.5 eV is the scaling factor relating to the normal hydrogen electrode scale (NHE) to the absolute vacuum scale. 49 Using the above equations, the calculated values of the CB and VB for Fe 3 O 4 were found to be 0.56 eV and 1.98 eV, respectively, whereas the values for BiVO 4 were 0.30 eV and 2.77 eV, respectively.…”

Potential of Iron Oxides in Photovoltaic Technology

“…93 Some studies reported that the FeO could have an insulating behavior generated by the charge transfer of the 2p state of oxygen to the 3d state of iron. 92 Fe 3 O 4 has a band gap at around 2.85 eV, 94 and has been studied for its potential in photocatalyst and PV applications due to its good optical properties, excellent light absorption, and good optoelectronic properties. 95 Fe 2 O 3 is the highest oxygen state of iron oxides, having a band gap depending on their crystal structures.…”

Crystal Structure, Morphology, and Magnetic Properties of Magnetic Nanocomposites with Iron Oxide Core and Zinc Oxide/Titanium Oxide Shell

“…Nishad et al also reported that the core-shell particle size of Fe3O4@ZnO had a lower value of 39 nm, resulting in magnetic materials with luminescence responses [10]. Aguinaco et al performed another type of modification on Fe3O4, where Fe3O4 was composited with titanium oxide (TiO2), resulting in the material applicable as a solar photocatalytic [11]. Fe3O4/TiO2 can also be applied as a photodegradable material.…”