Pure-phase Bi2Fe4O9 nanoparticles with mullite-type structure were successfully fabricated through a facile and environmentally benign sol-gel process. According to the UV-Vis diffuse reflection spectrum, the multiband structure and the band edge position of the nanoparticles were confirmed, indicating the prominent absorption in the expanded visible-light region. As compared to the bulk, the visible-light-driven photocatalytic activity of the obtained nanoparticles was improved by 30-fold. The much improved photocatalytic efficiency of the sample mainly owed to the small crystal size and the multiband characteristic as well as the adding of H2O2 as electron scavenger and a source of hydroxide free radicals instead of Fenton-like reaction, leading to a low recombination of the photogenerated e(-)/h(+) pairs. (c) 2014 Elsevier B.V. All rights reserved.