▎ 摘　　要

In this paper, magnetic and structural properties' and graphene nanoparticles' influence on photocatalytic activity of BiFeO3 ceramics are reported. BiFeO3 ceramics were prepared by the sol-gel process and sintering at different temperatures from 400 to 700 degrees C to get phase pure BiFeO3 ceramics. X-ray diffraction patterns indicated pure phase with sharp peaks for sample sintered at 600 degrees C. Rietveld analysis showed the presence of pure phase samples of rhombohedral perovskite structure with R3c symmetry expect sample sintered at 700 degrees C. Bond valance sum analysis showed that Fe cations are inadequately bonded, while the Bi cations are excessively bonded in BiFeO3 structure. First-order Raman modes along with few second order modes belonging to rhombedral crystal were observed in Raman spectra. X-ray photoelectron spectroscopy showed the presence of mixed oxidation states (Fe2+/Fe3+) with Fe3+ dominance. Vibrating sample magnetometer analysis indicated weak ferromagnetism along with strong dependence of magnetic characteristics on sintering temperatures. The ferromagnetic saturation magnetization (M-FM(S)) and remnant magnetization decreased from 0.057 to 0.0049 emu/g and 0.0150 to 0.0009 emu/g, respectively, with increasing sintering temperature. The photocatalytic activity of pure BiFeO3 and graphene nanoparticle-modified BiFeO3 samples was recorded. It was observed that BiFeO3 with graphene nanoparticles exhibited good degradation toward methylene blue dye when exposed to visible light irradiation.