Recently, bismuth ferrites have attracted great interest in the field of photocatalysis due to their magnetic nature and narrow band gap. Herein, nanohybrids of lanthanum (La) and manganese (Mn) co-doped BiFeO3 (BLFMO)/graphene nanoplatelets (GNPs) have been synthesized. The hybrids were prepared by two different but simple and low-cost synthesis routes: (i) co-precipitation (namely the C-series), and (ii) hydrothermal (namely the H-series) methods. This article details a comparison of the C-series and H-series BLFMO/GNP nanohybrids based on their photocatalytic activity and band gap. The H-series nanohybrids showed a more crystalline structure, reduced band gap and less dye removal compared to the C-series nanohybrids. The enhanced dye removal (92%) of the C-series nanohybrids is attributed to their high surface area (55 m2 g-1) due to GNP incorporation inside the BLFMO/GNP nanohybrids. The higher surface area enables more adsorption of dye molecules over the catalyst surface under dark conditions. In addition, the band gap of the BLFMO/GNP nanohybrids was reduced from 2.04 eV (pure BiFeO3) to 1.40 eV (BLFMO/GNPs) because of the presence of new donor energy levels with Mn loading. The calculated particle sizes from Scherrer's formula were 19.3-23.5 nm (C-series) and 22.5-26 nm (H-series). The estimated particle size calculated via transmission electron microscopy (TEM) is approximately 31 nm for the C-series nanohybrids. The graphene based nanohybrids significantly enhanced dye removal compared to pure BiFeO3 (44%) under visible light irradiation. The low cost, easy preparation and higher catalytic activity of the BLFMO/GNP nanohybrids reported here make nanohybrids suitable candidates for practical applications.
ASJC Scopus subject areas
- Chemical Engineering(all)