Bi@Bi2O3@carboxylate-rich carbon core-shell nanosturctures (Bi@Bi2O3@CRCSs) have been synthesized via a one-step method. The core-shell nanosturctures of the as-prepared samples were confirmed by Xray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman spectroscopy. The formation of Bi@Bi2O3@CRCSs core-shell nanosturctures should attribute to the synergetic roles of different functional groups of sodium gluconate. Bi@Bi2O3@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation (lambda > 420 nm) and shows an O-2-dependent feature. According to trapping experiments of radicals and holes, hydroxyl radicals were not the main active oxidative species in the photocatalytic degradation of MB, but O-2(center dot-) are the main active oxidative species. (C) 2013 Elsevier Ltd. All rights reserved.