One-step solvothermal synthesis of interlaced nanoflake-assembled flower-like hierarchical Ag/Cu2O composite microspheres with enhanced visible light photocatalytic properties

Abstract

Three-dimensional (3D) micro/nano hierarchical structure semiconductor catalysts not only inherit the excellent properties of single nanometer-size building blocks resulting from their high specific surface area and high activity but also provide the merits of high dispersion and easy recovery of microstructures. Herein, the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu₂O composite microspheres have been prepared via a one-step, environmentally friendly solvothermal method. Such interlaced nanoflake-assembled flower-like hierarchical Ag/Cu₂O composite microspheres show an excellent photocatalytic activity, which is 121 times faster than that of the commercial Cu₂O powders, and is one of the highest reported to date in the Ag/Cu₂O composite materials for the degradation of Methyl Orange (MO) under visible light illumination. Our experimental results for photodegradation of MO also indicate that the existence of Cu in the products does not favor high photocatalytic activity for Ag/Cu₂O composites, which may be due to the existence of excess metal in the products which provides the recombination centers for electron–hole pairs. After five consecutive cycles, the photocatalytic activity of the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu₂O composite microspheres almost remains unchanged, indicating that they are photostable during the photodegradation of MO. Most importantly, such micrometer-sized overall structures of the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu₂O composite microspheres enable them to be recycled and reused easily from solution by natural settlement in a short time. These results suggest that the interlaced nanoflake-assembled flower-like hierarchical Ag/Cu₂O composite microspheres had potential applications in visible light photocatalysis for environmental remediation.