Cu2S@ZnO hetero-nanostructures: facile synthesis, morphology-evolution and enhanced photocatalysis and field emission properties

A novel hierarchical three-dimensional (3D) Cu2S@ZnO heteroarchitecture was successfully synthesized by a facile three-step synthetic process. FESEM and TEM analyses revealed the formation of the hierarchical 3D structure of the as-prepared Cu2S@ZnO. The purity and crystalline phase of the individual component in the 3D Cu2S@ZnO were determined by a powder X-ray diffractogram. The formation of the hierarchical 3D structure of the as-prepared Cu2S@ZnO leads to multiple p–n junctions formed at p-Cu2S@n-ZnO interfaces, which promote the generation and separation of photoinduced electrons and holes and thus improves the photocatalytic efficiency tremendously. According to the data, after irradiation for 40 min, the remaining MB in solution is about 35% for Cu2S nanoflowers and 9% for Cu2S@ZnO binary nanoflowers. Also, the increases in the overall aspect ratio and the ZnO nanoparticles act as extra emission sites, which help to enhance the field emission properties. The turn-on fields and threshold fields for the Cu2S nanoflowers as well as the Cu2S@ZnO nanoflower hybrid emitters are 3.3 and 9.2 V μm−1, 2 and 6.3 V μm−1, respectively. Compared with the Cu2S nanoflowers, the Cu2S@ZnO hetero-nanoflowers show excellent improvements in both photocatalytic and field emission applications.