Sono-synthesis of nanocrystallized BiFeO3/reduced graphene oxide composites for visible photocatalytic degradation improvement of bisphenol A

Abstract

This study sustainably developed bismuth ferrite/reduced graphene oxide (BiFeO3/rGO) nanocomposites by introduction of graphene oxide (GO) in the structure of BiFeO3 magnetic nanoparticles (BFO MNPs) in a short term ultrasonic treatment. Successful reduction of GO into rGO took place during ultrasonic nanocomposite (BFO/rGO) preparation. The synthesized BFO MNP/rGO composites were used to improve the photocatalytic degradation of aqueous bisphenol A (BPA) under visible irradiation. BFO MNPs with sphere-like shapes and an average size of 10–15nm, smaller than pure BFO MNPs, were homogeneously distributed on the surface of rGO. d spacing values of 3.6Å and 1.2Å, corresponding to the (101) and (012) lattice planes of BFO MNPs in BFO/rGO nanocomposites, indicate well developed nanocrystallites of BFO MNPs in the nanocomposites. The lower band gap energies of 1.9–2.0eV were identified for BFO MNP/rGO composites as compared to 2.1eV for BFO MNP. BFO MNP/rGO composites with 4wt% of GO exhibited almost complete photocatalytic degradation (>99%) of the BPA under visible light irradiation and the significant reduction of the total organic carbon (TOC) after irradiation for 70min (78%) and 120min (100%). Such high photocatalytic degradation for the BFO MNP/rGO composite was mainly attributed to the increased interaction between BPA and rGO due to the very large π-conjugation plane of graphene, decrease in particle size and band gap energy and the lower recombination rate of electron–hole pairs due to the strong electron transfer ability of rGO in the nanocomposites.