The influence of oxygen vacancies on the dielectric relaxation behavior of pure and Eu-substituted BiFeO₃ nanoparticles synthesized by a sol–gel technique has been studied using impedance spectroscopy in the temperature range of 90 °C to 180 °C.

Photocatalysis is a multifunctional phenomenon that can be employed for energy applications such as H₂ production, CO₂ reduction into fuels, and environmental applications such as pollutant degradations, antibacterial disinfection, etc. In this direction, it is not an exaggerated fact that TiO₂ is blooming in the field of photocatalysis, which is largely explored for various photocatalytic applications. The deeper understanding of TiO₂ photocatalysis has led to the design of new photocatalytic materials with multiple functionalities. Accordingly, this paper exclusively reviews the recent developments in the modification of TiO₂ photocatalyst towards the understanding of its photocatalytic mechanisms. These modifications generally involve the physical and chemical changes in TiO₂ such as anisotropic structuring and integration with other metal oxides, plasmonic materials, carbon-based materials, etc. Such modifications essentially lead to the changes in the energy structure of TiO₂ that largely boosts up the photocatalytic process via enhancing the band structure alignments, visible light absorption, carrier separation, and transportation in the system. For instance, the ability to align the band structure in TiO₂ makes it suitable for multiple photocatalytic processes such as degradation of various pollutants, H₂ production, CO₂ conversion, etc. For these reasons, TiO₂ can be realized as a prototypical photocatalyst, which paves ways to develop new photocatalytic materials in the field. In this context, this review paper sheds light into the emerging trends in TiO₂ in terms of its modifications towards multifunctional photocatalytic applications.

The perovskite family is comprised of a great number of members because of the possible and flexible substitution of numerous ions in its system.