Visible-light-driven photocatalysis of anisotropic silver nanoparticles decorated on ZnO nanorods: Synthesis and characterizations

Having junctions of noble metals and semiconductors is an appealing approach to fabricate a robust photocatalyst for the complete degradation of organic pollutants with visible light activation. Herein, we synthesize Ag/ZnO nanorods (NRs) by a two-step chemical route. ZnO NRs are first grown via a solvothermal process with a length and a diameter of about 300 +/- 10 nm and 60 +/- 3 nm, respectively. Anisotropic silver nanoparticles (Ag NPs) are then deposited on the surface of the ZnO NRs by a self-assembly process. Thereby, the spatial separation of electron-hole (e- h+) pairs in the Ag/ZnO NR composites is considerably enhanced because of the localized surface plasmon resonance (LSPR) effect derived from Ag NPs and the suitable energy band alignment between ZnO and Ag. By taking this advantage, Ag/ZnO NRs outperform bare ZnO NRs in photocatalytic activity against rhodamine B (RhB). The Ag/ZnO NRs retain their excellent performance of 86% even after being used repetitively for three recycling rounds. The free radicals trapping test suggests that photogenerated electron is the key factor in the photocatalytic RhB degradation of Ag/ZnO NRs.

Automated summary

The combination of noble metals and semiconductors can create an efficient photocatalyst for degrading organic pollutants with visible light activation. In this study, Ag/ZnO nanorods were synthesized and showed superior photocatalytic activity compared to bare ZnO nanorods, thanks to the enhanced separation of electron-hole pairs and the localized surface plasmon resonance effect derived from silver nanoparticles.