Microemulsion synthesis of Ga and Sr doped BiFeO3 nanoparticles and evaluation of their ferroelectric, optical, dielectric and photocatalytic properties

Abstract

A series of Ga and Sr doped bismuth ferrite (BiFeO₃) was synthesized using a facile microemulsion technique and characterized using XRD, SEM, Raman, PL and UV–vis techniques. The XRD and Raman study revealed the rhombohedral phase of Bi1-xSrxFe1-xGayO3 with R3‾c space group. The average crystalline size was in range of 28–42 nm. From P-E loop, the saturation polarization (Ps), coercivity (Hc) and remanence (Pr) were determined and value of Pr and Ps increased with increasing dopant contents. Furthermore, there was a decline in dielectric loss with increased frequency and dopant content. The PL revealed that the highly substituted material had lower re-combination rate and higher charge (e−-h+) separation, which was finally responsible for its enhanced photo-catalytic activity. For Ga and Sr doped BiFeO₃, UV–Vis absorption edge exhibited substantial red shift thus reducing bandgap from 1.91 to 1.19 eV for highest doped composition. Finally, the photocatalytic activity of the material was investigated using methyl orange (MO) as model contaminant. Bi1-xSrxFe1-xGayO3 exhibited much better photocatalytic efficiency and degraded 87% dye in comparison to pristine BiFeO3 (66%) within 70 min under solar light. Also, stability of samples was demonstrated through re-cycling experiment. Bi1-xSrxFe1-xGayO3 had higher stability and reusability compared to BiFeO₃. Based on these findings, Bi1−xSrxFe1−yGayO3 material may find use in high frequency devices and photo-catalytic applications for treatment of industrial wastes due to its promising dielectric and photo-catalytic outcomes.