Microwave-assistant hydrothermal synthesis of SnO2@ZnO hierarchical nanostructures enhanced photocatalytic performance under visible light irradiation

In this paper, for the first time, SnO2@ZnO hierarchical nanostructures (HNSs) were synthesized by a simple two-step microwave-assistant hydrothermal method. Systematical characterization of the SnO2@ZnO HNSs revealed that the ruffle SnO2 nanowires (NWs) were uniformly and tightly grown on the entire surface of each ZnO nanoflowers (NFs). The photocatalytic performance of the SnO2@ZnO HNSs showed a remarkably enhanced photocatalytic performance under visible light irradiation (400 nm <= lambda <= 800 nm). The photoluminescence (PL) spectrum results indicated that the defect related energy level is the main mechanism of the photocatalytic performance under the visible light irradiation. The unique morphology and heterojunction structures in SnO2@ZnO HNSs were the core enhanced mechanism in photodegradation process. The advantage endowed with the microwave-assistant hydrothermal method can result in the efficient spatial charge separation between ZnO nanorods (NRs) and SnO2 NWs and reduce the charge recombination along the heterojunction, which makes SnO2@ZnO HNSs a highly promising for photocatalytic applications.