Rapid preparation and photocatalytic properties of octahedral Cu₂O@Cu powders

To improve the photocatalytic properties of Cu₂O, octahedral Cu₂O@Cu powders were prepared by a convenient and rapid two-step liquid phase reduction method. Glucose (C₆H₁₂O₆) and thiourea dioxide (CH₄N₂O₂S, TD for short) were used as pre-reductant and secondary-reductant separately. The microstructure and composition of the products obtained after the reduction processes were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). With the increasing of TD content, the secondary reduced products changed from solid octahedral Cu₂O to octahedral Cu₂O@Cu composites and finally hollow octahedral Cu₂O/Cu composites. The corresponding calculated mass of Cu increased from 6.2 wt% to 80.2 wt%. The photocatalytic behavior of the reduced particles were analyzed by monitoring the degradation of methyl orange solution (MO for short) and electrochemical tests. Photocatalytic performance tests showed that octahedral Cu₂O@Cu powders had an excellent photocatalytic activity. The MO degradation rate was improved from 1.4% for photocatalysts without CuNPs to 92.9% after introducing 13.4 wt% CuNPs under visible light irradiation for 60 min. This simple and rapid synthesis process allowed for the fabrication of octahedral Cu₂O@Cu material with photocatalytic performance superior to pure octahedral Cu₂O and hollow octahedral Cu₂O/Cu materials.