Band‐Gap Engineering and Enhanced Photocatalytic Activity of Sm and Mn Doped BiFeO3 Nanoparticles

Bi 1‐ x Sm x Fe 1‐ y Mn y O 3 ( BSFMO , x = 0.0, 0.05; y = 0.0, 0.05, 0.10, 0.15, 0.20, 0.25) nanoparticles were synthesized by using double solvent sol–gel method. Photocatalytic activity was investigated under UV and visible‐light illumination. The structural, morphological, and optical properties were analyzed by X‐ray diffraction, scanning electron microscopy, and UV ‐vis spectroscopy respectively. The crystallite size of BiFeO 3 ( BFO ) decreases from (57.3–17.2 nm) with the increase in Sm and Mn‐doping concentration. The surface morphology shows that the pure and Sm‐doped BFO nanoparticles are irregular in shape but changes to spherical shape after Mn‐doping up to 25%. The band‐gap engineering of BFO nanoparticles is achieved by co‐doping of Sm and Mn. The band‐gap of BFO could be tuned successfully from 2.08–1.45 eV , which may be due to the distortion induced in Fe‐O octahedron and the rearrangement of molecular orbitals. These results give rise to enhanced photocatalytic activity by degradation of organic dyes ( MB , CR , and MV ) under the visible‐light illumination.