Systematic study of electronic properties of Fe-doped TiO2 nanoparticles by X-ray photoemission spectroscopy

Abstract

The importance of investigating the electronic structure of Fe doped TiO2 nanoparticles lies in understanding their various magnetic and optical applications. In this study Fe doped TiO2 nanoparticles were synthesized by sol gel method in a wide range of Fe/Ti molar ratios (1, 3, 5, 8, and 10 %) and post annealing at 400, 600 and 800 o C in air. The structure and size of nanoparticles were studied by X-ray diffraction and transmission electron microscopy, respectively. Systematic study of the existing states of Fe ions in Fe doped TiO2 and transformation of the existing states as a function of annealing temperature and Fe concentration were carried out utilizing high-resolution X-ray photoemission spectroscopy (XPS). The XPS results showed that Fe was present in all samples while Fe ions were detected in mixed valence (Fe 2+ and Fe 3+ ) states. The Fe 3+ ions were dominant in the surface region of the nanoparticles. Moreover, the Ti in Fe:TiO2 nanoparticles was assigned to the Ti 4+ while a small shift towards lower binding energies was observed upon increasing the annealing temperature and dopant level. This confirms the successful incorporation of Fe into TiO2, and the shifts in binding energies were attributed to the anatase to rutile transformation. The results verify that doping by Fe up to 10% do not exceed the limit of Fe substitutation into TiO2 lattice.

Simultaneous Photocatalytic Esterification and Addition Reaction of Fatty Acids in Kemiri Sunan (Reutealis trisperma sp.) Oil over CuO/TiO2 Catalyst - A Novel Approach

“…The photoelectron peak of O 1s is found at binding energy of 529.9 eV that corresponds to the lattice oxygen in TiO2. This result is similar with previous study conducted by Nasralla et al [30]. The measuring binding energies of Cu p1/2 and Cu p3/2 are 951 and 931.9 eV, respectively.…”

Enhanced Fe-TiO2 Solar Photocatalysts on Porous Platforms for Water Purification

“…Nevertheless, in terms of the increase of the TiO 2 photocatalytic activity with iron doping, some studies reported the opposite behavior. Multiple factors can contribute to the inconsistencies reported in the literature, including disparities in synthesis methods, annealing temperatures, the organic compounds used for the photocatalytic tests, and the concentration of the iron dopant [ 42 , 43 , 44 ].…”

Photocatalytic Degradation of Polyethylene Microplastics and Disinfection of E. coli in Water over Fe- and Ag-Modified TiO2 Nanotubes

“…One of the considerations that can be taken to overcome this weakness is by incorporating metals ions into TiO2 structure [19]. Among the wide range [17] of available choices, Fe 3+ was of tremendous interest owing to its similar ionic radii to Ti 4+ that facilitates incorporation into the crystal lattice of TiO2 [20][21][22]. On the other hand, Ag is also a promising promotor for TiO2 as it is a noble metal that could reduce the recombination rate of the photogenerated electrons and holes through the formation of the Schottky Barrier on the Ag-TiO2 interface.…”