Vertically aligned ZnO nanowire arrays tip-grafted with silver nanoparticles for photoelectrochemical applications.

Herein, we demonstrate that uniform Ag nanoparticles could be directionally grafted on the tip of ZnO nanowire arrays by a simple photo-reduction method. Furthermore, the structure, position, and amount of Ag nanoparticles supported on ZnO nanowire arrays could be further rationally tailored by changing the reaction parameters such as the category, concentration of reagents, and annealing temperature. Moreover, their photoelectrochemical performances under both UV-vis and monochromatic light irradiation have been explored. Interestingly, the photocurrent density of Ag-ZnO heterostructures could reach up to 2.40 mA cm(-2), which is much higher than that of pure ZnO nanowire arrays. It has been proposed that the formation of ZnO nanowire arrays tip-grafted with Ag nanoparticles could promote the effective separation and directional transfer of photoexcited electron-hole pairs, and thus enhance the photoconversion properties.