Synthesis and photocatalytic application of oriented hierarchical ZnO flower-rod architectures

An oriented hierarchical ZnO flower-rod arrays (FRs) were prepared on indium doped tin oxide (ITO) glass using a facile solution-based method assisted with ZnO seed layer. And the as-prepared ZnO FRs/ITO was used as a convenient photocatalytic device that recycled without centrifugation. The results show that ZnO FRs are wurtzite phase with single crystalline grown along the [0   0   1] direction. The photoluminescence (PL) spectra illustrate that there are more oxygen vacancies on the surface of ZnO FRs compared with ZnO nanoparticles (NPs). The electrochemical methods using Rhodamine B (RhB) as electrolyte are also performed to study on the photodegradation mechanism where RhB is acted as photocatalytic substrate. For ZnO FRs, the higher photoinduced currents under UV irradiation and current density prove that the recombination of electron–hole pairs is restrained with oxygen vacancies, and the lower charge transfer resistance suggest that the charges could move quickly through ZnO oriented structures. Therefore, the photocatalytic activity is enhanced by ZnO FRs compared with ZnO NPs, and RhB degradation efficiency of ZnO FRs photocatalysts is nearly 100% by UV irradiation for 1.5   h.