Morphology Evolution of Cu2O from Octahedra to Hollow Structures

Octahedral Cu2O crystals with an edge length about 1 μm were synthesized by reducing a copper-citrate complex with glucose. The morphology and structure of Cu2O particles were greatly affected by the concentration of glucose, reaction temperature, and time. When the concentration of glucose increased from 0.6 to 1.6 M, the morphology of Cu2O could be changed from octahedral single crystals to spherical polycrystals. When the reaction time was prolonged from 6 to 36 h, solid Cu2O octahedra could be changed to a mixture of hollow Cu2O octahedra and irregular Cu particles. After removing Cu particles, pure Cu2O hollow octahedra could be obtained. The formation mechanism of hollow Cu2O octahedra was discussed. Similarly, hollow Cu2O spheres could also be obtained using this method. The prepared hollow octahedral Cu2O particles exhibited a higher photocatalytic activity for photodegradation of p-nitrophenol aqueous solution under visible-light illumination than other Cu2O particles with different morphologies (hollow spheres, solid octahedra, and solid spheres).