computational modeling

The fabrication of sustainable and efficient metal oxide-based semiconductor materials for effective degradation of environmental pollutants and other applications are currently attracting major interest from researchers. For this reason, magnetic iron oxide (Fe3O4) and zinc incorporated magnetic iron oxide (Zn@Fe3O4) nanoparticles were successfully synthesized by a co-precipitation method and tested for their physical properties and also as a photocatalysts for the degradation of toxic dye from the environment. The photocatalyst were analyzed by the use of scanning electron microscopy (SEM), x-ray diffraction (XRD) and Ultra-Violet Visible spectrophotometer to evaluate their morphology, crystallinity and band gap properties, respectively. The photocatalytic degradation performance of synthesized Fe3O4 and Zn@Fe3O4 was studied for their degradation efficiency on methylene blue (MB) dye. The photocatalytic activity of Fe3O4 was affected by doping with Zn ion. The highest methylene blue degradation (83.80 % and 70.50 %) for Fe3O4 and Zn@Fe3O4 were obtained at 0.5 g dose. The XRD and SEM results approved the existence of Fe3O4 and Zn@Fe3O4, and also highlighted the successful entrance of zinc ion onto Fe3O4. The introduction of zinc dopant into Fe3O4 lattices increases the band gap from 2.77 eV to 2.80 eV. The study of electronic structure of methylene blue was examined through quantum chemical calculations using density functional theory method (DFT) in order to give an insight on the nature of MB interaction with synthesized photocatalyst. The DFT results revealed that the nitrogen atom of the MB molecule is the favorite sites of interaction with the metal oxide surface. Furthermore, the experimental findings showed that magnetic iron oxide demonstrated a good photocatalyst in degradation of methylene blue as compared to the zinc doped magnetic iron oxide particle.

In this contribution, density functional theory-based calculations have been carried out to assess the electronic, photocatalytic and optical properties of Ce1-xTixO2 system. Ti incorporation leads to a decrease of Ce 4f states and enhancement of Ti 3d states in the bottom of conduction band. Furthermore, it was found that doping ceria with Ti-like transition metals could evidently shift the absorption of pure CeO2 towards higher wavelength range. These findings can provide some new insights for designing CeO2-based photocatalysts with high photocatalytic performance. To the best of our knowledge, this investigation calculates Mullikan’s charge transfer of Ce1-xTixO2 system for the first time. Charge transfer reveals an ionic bond between Ce or Ti and O, and covalent bonds between Ce and Ti atoms in the studies systems.