A promising Z-scheme heterojunction via loading Ag/AgCl into porous Co3O4 derived from ZIF-67 for visible light driven photocatalysis

摘要

It is of great concern to fabricate Z-scheme heterojunction photocatalyst for promoting the separation efficiency of photo-generated carriers and maintaining higher redox abilities. Herein, we design a promising Z-scheme heterojunction via loading Ag/AgCl into porous Co3O4 which is derived from the pyrolysis of ZIF-67 for visible light driven photocatalysis. After moderate calcination of ZIF-67 at 400 degrees C, the resulted porous Co3O4 (C400) with the same dodecahedral morphology as ZIF-67 is proved to be an effective host for incorporation of photosensitive semiconductor Ag/AgCl. Due to the suitable conduction and valence band potential of C400 and Ag/AgCl, superoxide (center dot O-2(-)) and hydroxyl radicals (center dot OH) are successfully generated, which further promote the photo-redox reaction. As a result, the fabricated Ag/AgCl/C400 exhibits superior catalytic activity (3.9 times higher than Ag/AgCl) and high catalytic efficiency which are attributed to the improved the light response and the separation efficiency of photogenerated carriers. The structures, morphologies, optical and electrochemical properties of these prepared photocatalysts are systematically investigated by various characterization methods, and a detailed photocatalytic mechanism is proposed. This work provides a new insight into the design of Z-scheme heterojunction photocatalyst.