Magnetically separable Cu2O/chitosan–Fe3O4 nanocomposites: Preparation, characterization and visible-light photocatalytic performance

Abstract A novel magnetically-separable visible-light-induced photocatalyst, Cu 2 O/chitosan–Fe 3 O 4 nanocomposite (Cu 2 O/CS–Fe 3 O 4 NC), was prepared via a facile one-step precipitation–reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu 2 O/CS–Fe 3 O 4 NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV–vis/DRS. The photocatalytic activity of Cu 2 O/CS–Fe 3 O 4 NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu 2 O/CS–Fe 3 O 4 NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu 2 O was wrapped in chitosan matrix embedded with Fe 3 O 4 nanoparticles. The tight combination of magnetic Fe 3 O 4 and semiconductor Cu 2 O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu 2 O/CS–Fe 3 O 4 NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B were still above 87% after five reaction cycles, indicating that Cu 2 O/CS–Fe 3 O 4 NCs had excellent reusability and stability.