A unique organic-inorganic hybrid nanocomposite was designed and synthesized by chemically anchoring the cationic collagen-based derivatives onto the surface of Fe3+/TiO2 nanospheres for the significant enhancement in photocatalytic activity under the visible light irradiation. The NMR analysis suggested the successful fabrication of cationic collagen-g-PDMC as grafted materials. In addition, the chemical structures, morphologies and properties of these samples were systematically characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectrum, ultra violet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). And obtained results clearly demonstrated that Fe3+ ions diffusing into TiO2 lattice could be responsible for slightly reducing the average diameter of nanospheres to about 125 nm, promoting phase transition from anatase to rutile to some extent and extending the light harvesting range into visible region markedly. Meanwhile, the achievement that collagen-g-PDMC molecules had been covalently immobilized onto the surface of Fe3+/TiO2 nanoparticles was also well supported by the information acquired. Furthermore, the photocatalytic activities of all the as-prepared products were carefully evaluated by adopting photocatalytic decoloration of methyl orange (MO) solution under the solar direct irradiation, and the sample CFT-3 performed the best in the photocatalytic degradation process, which was mainly attributed to the energetic synergistic effect brought about by Fe3+ ions doping and collagen-g-PDMC molecules immobilized on the surface. (C) 2015 Elsevier B.V. All rights reserved.