Harnessing Ag nanofilm as an electrons transfer mediator for enhanced visible light photocatalytic performance of Ag@AgCl/Ag nanofilm/ZIF-8 photocatalyst

An Ag@AgCl/Ag nanofilm/ZIF-8 composite photocatalyst was successfully constructed for the first time by loading Ag@AgCl and Ag nanofilm on the surface of ZIF-8 simultaneously via a simple deposition-photoreduction method. The formed Ag nanofilm was harnessed as a mediator to transfer photo-induced electrons from the plasmonic Ag@AgCl nanostructure to ZIF-8 for enhancing the photocatalytic reaction rate with visible light. The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The first-order kinetic constant of MB degradation over Ag@AgCl/Ag nanofilm/ZIF-8 (14.762 h(-1)) was nearly 2 times of Ag@AgCl/ZIF-8 (7.932 h(-1)). The electrochemical impedance spectra, photoelectric conversion spectra and ESR DMPO-O-2(center dot-) species spectra revealed that AFZ had a lower resistance, higher photocurrent density and more generation of superoxide radical than those of AZ, meaning that the extended interface between Ag nanofilm and ZIF-8 could promote the quick electrons transfer and electron-hole pairs separation. This work provides a new type electrons transfer mediator in fabrication of efficient plasmonic photocatalysts. (C) 2016 Elsevier B.V. All rights reserved.