Structural, Optical and Photocatalytic Properties of Bi₂O₃/Mn₃O₄ Nanocomposites

Abstract This research aims to develop binary Bi 2 O 3 /Mn 3 O 4 heterostructures for the mineralization of pollutants in water. For this purpose, pure Bi 2 O 3 , Mn 3 O 4 , and Bi 2 O 3 /Mn 3 O 4 nanocomposite samples are synthesized. Structural analysis exhibits the formation of a mixed‐phase solid oxide solution. This is verified via FTIR spectroscopy where an additional peak observed at 723 cm −1 indicating Bi─O─Mn stretching vibration. The binary Bi 2 O 3 /Mn 3 O 4 nanocomposite has increased visible light absorption and narrow bandgap when compared to pure Bi 2 O 3 . The synthesized Bi 2 O 3 /Mn 3 O 4 nanocomposite exhibits 76.4% degradation of methylene Blue (MB) under solar light irradiation with a pseudo‐first‐order rate constant of 0.00572 min −1 superior to pure Bi 2 O 3 and Mn 3 O 4 nanoparticles. This significant increase in the photocatalytic activity of Bi 2 O 3 /Mn 3 O 4 nanocomposite is due to the direct z‐scheme mechanism of charge transfer between Bi 2 O 3 and Mn 3 O 4 through greater redox potential and generation of surface defects that induce additional active sites for the adsorption of organic dye which trap photoinduced electrons and holes resulting a reduction in electron–hole recombination rate.