Facile green synthesis of ytrium-doped BiFeO3 with highly efficient photocatalytic degradation towards methylene blue

Abstract

Abstract Bismuth ferrite (BiFeO3) is considered as one of the most promising materials in the field of multiferroics with great potentials in photocatalysis due to their excellent properties of relatively small band gap, stable structures, and low cost. In this work, a facile green route was successfully used for the fabrication of high-purity yttrium-doped and undoped bismuth ferrite (BiFeO3) nanoparticles. κ-carrageenan seaweed was used as a biotemplate for the construction of the material. The obtained products were characterized and the photocatalytic effect of doped and undoped BiFeO3 were evaluated on the degradation of methylene blue (MB) under direct sunlight. The formed particles are in the range of 80–90 nm that exhibited morphology of rhombohedral perovskite structure as confirmed by FESEM and HRTEM analysis. Decreasing of band gap energy from 2.07 eV to 2.05 eV as the concentration of yttrium dopant increased significantly affected their photocatalytic behaviour. There was a remarkable improvement in the photocatalytic activity of 1% of yttrium-doped BiFeO3 towards the decomposition of methylene blue (MB) under direct sunlight irradiation. This was attributed to the strong absorption of visible light and the effective separation of photoinduced e− and h + pair, as compared to the pristine BiFeO3. In addition, the influence of operational parameters on the removal efficiency of MB, such as catalyst dosage and initial dye concentrations, was optimized as a function of time. The kinetics of the photocatalytic MB removal was later found to follow Langmuir Hinshelwood model.