One-step and single source synthesis of Cu-doped ZnO nanowires on flexible brass foil for highly efficient field emission and photocatalytic applications

Abstract

In the present work, Cu-doped ZnO nanowires have been fabricated by direct heating method on brass foils under ambient condition. The reaction temperature was not only controlling the morphology of Cu-doped ZnO nanostructures, but also influencing the Cu doping concentration. Cu-doped ZnO nanowires have good geometric structures, appropriate substrates, and doping states for field emission, which led to very low turn-on and threshold fields. In addition, the Cu-doped ZnO nanowires exhibit strong green emission attributed to oxygen vacancies and small UV emission from band gap. The Cu-doped ZnO nanowires revealed much higher photodegradation efficiency than commercial TiO2 nanopowders. This result is attributed to increase the separation of photogenerated electron-hole pairs by Cu ions substitute in ZnO lattices and the higher surface-to-volume ratio to enhance the photocatalytic activity. Furthermore, the reusability test can demonstrated that the Cu-doped ZnO nanowires on the brass foils still maintained high photocatalytic activity for the degradation of three kinds of organic pollutants even after five cycles without any obvious decline. The results demonstrate that Cu-doped ZnO nanowires on the brass foils shall be also promising in many related areas, such as solar energy conversion, water splitting, and energy storage.