Importance of calcium doping for the enhanced photocatalytic performance of BiFeO₃ nanoparticles in visible light

Abstract This study investigates the influence of calcium doping on the structural, optical, and photocatalytic properties of bismuth ferrite nanoparticles. Pure and calcium-doped BiFeO 3 nanoparticles (Ca@BFO) with doping concentrations of 0.05, 0.075, and 0.1 M were synthesized via a sol–gel method. X-ray diffraction analysis confirmed structural modifications and crystallite size reduction upon doping. Raman spectroscopy indicated enhanced peak intensities for Ca@BFO samples, suggesting improved structural ordering. UV–vis spectroscopy demonstrated a reduction in the wide bandgap to 2.24 eV for the 0.1 M Ca-doped BFO, leading to enhanced visible-light absorption. Photocatalytic activity was assessed by the degradation of methylene blue under different pH conditions, with the best performance observed at pH 8 for the 0.1 M Ca-doped BFO sample. Stability and reusability studies showed minimal activity loss over multiple cycles. These findings highlight the potential of Ca@BFO nanoparticles for efficient photocatalysis and environmental remediation applications.