Structural, magnetic, optical, and photocatalytic properties of Ca–Ni doped BiFeO 3 nanoparticles

In this article, we have studied the structural, magnetic, optical, and photocatalytic properties of Bi 1− x Ca x Fe 1− x Ni x O 3 multiferroics synthesized by sol–gel method. X-ray diffraction predicted the superposition of two structural phases (rhombohedral- R3c + orthorhombic- Pnma ) for ( x = 0.05, 0.10) samples. Correspondingly, drastic variations in the Raman modes were detected at low and high wavenumbers with increasing the Ca–Ni content. The larger change in the magnetic parameters at room temperature was identified for Bi 0.90 Ca 0.10 Fe 0.90 Ni 0.10 O 3 nanoparticles caused by the formation of a new orthorhombic phase. The XPS spectroscopy study supported the magnetic enhancement in x = 0.10 samples due to increasing concentration of Fe 2+ , Ni 2+ ions, and oxygen vacancies. The shift of ESR pattern with doping agrees with the magnetization values. The energy band gap values were altered by increasing the Ca–Ni content in BiFeO 3 samples, from 2.22 to 2.05 eV. The photocatalytic activity of Ca–Ni doped BiFeO 3 photocatalyst showed higher degradation rate (− 0.035/min) of Methylene blue (MB) in comparison to pure BiFeO 3 .