Facile synthesis of a BiFeO3/nitrogen-doped graphene nanocomposite system with enhanced photocatalytic activity

In this study, BiFeO3 (BFO) nanoparticles were synthesized via the sol-gel route and BFO/nitrogen-doped graphene (NG) nanocomposites (BFO/NG, NG: 1%, 2%, 3%, 4%, 5%, and 6%) were prepared by dispersing the BFO nanoparticles and NG in ethanol solution, before thermal drying. The structural and morphological properties of the pure BFO nanoparticles, NG, and BFO/NG nanocomposites were studied by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy. The average crystallite size of the BFO nanoparticles was 57 nm. The SEM observations demonstrated that the BFO nanoparticles were well anchored on the NG. The photocatalytic activities of the as-synthesized samples were calculated based on the degradation of methyl orange under simulated sunlight irradiation. The BFO/NG nanocomposites exhibited enhanced photocatalytic activity compared with the pure BFO nanoparticles. The enhanced photocatalytic performance was attributed to the efficient transfer of photogenerated electrons from the BFO nanoparticles to NG, thereby leading to the increased availability of h+ for the photocatalytic reaction. Furthermore, hydroxyl (⋅OH) radicals were detected using the photoluminescence technique with terephthalic acid as a probe molecule and they were generated on the irradiated pure BFO nanoparticles and BFO/NG nanocomposites.