Synthesis and optimization of ag-zno heterojunction composite nanofibers for enhanced photocatalytic activity

In this study, Ag-ZnO heterojunction composite nanofibers with an average diameter of about 100 nm and coupled Ag nanoparticles with a size of 10 nm were synthesized by facile electrospinning followed by thermal treatment whereby the Ag content was tuned by controlling the precursor concentration. Rhodamine B (RhB) was employed as a representative dye pollutant to evaluate the ultraviolet (UV) and visible light photocatalytic activity of the pure ZnO and Ag-ZnO composite nanofibers. The photocatalytic activity of 1.5 at% Ag-ZnO nanofibers toward RhB degradation was the greatest, outperforming pure ZnO nanofiber by a factor of more than 5 times. Further increasing the Ag content led to lower photocatalytic activity, most likely due to the growth of the Ag nanoparticles. It was found that the enhanced photocatalytic activity is caused by the heterojunction structure promoting the charge separation of the photogenerated charge carriers, while the effect of surface plasmon resonance by the Ag nanoparticles on the photoreactivity is insufficient. The Ag-ZnO nanofibers show great promise as innovative and highly performing photocatalyst for photocatalytic waste-water treatment.