CdS nanowires decorated with Cu2O nanospheres: Synthesis, formation process and enhanced photoactivity and stability

CdS/Cu2O heterostructural materials were successfully synthesized by a solvent-thermal process followed by a chemical bath deposition process. Structures and morphologies of the obtained CdS/Cu2O composites were characterized by XRD, SEM, and TEM; the experimental results indicate that the surface of CdS nanowires (NWs) is decorated with spherical Cu2O whose diameter ranges from 100 to 200 nm. Through crystal shape-evolution, the formation process of these hierarchical nanostructures was rationally proposed. Briefly, in the chemical bath deposition process, Cu(OH)2 colloids generate firstly, and then the colloids transform into nanobelts after adding ascorbic acid (AA). With the reaction time further increasing, nanobelts aggregate together to form the hierarchical nanospheres on the surface of CdS NWs. The photoactivity of CdS/Cu2O composite for methyl orange (MO) photodegradation was investigated in detail. The obtained high photocatalytic efficiency can be attributed to the heterojunction structure, which results in the efficient separation of photo-generated electrons and holes.