Facile construction of a ZIF-67/AgCl/Ag heterojunction chemical etching and surface ion exchange strategy for enhanced visible light driven photocatalysis.

It is of great importance to design and fabricate heterojunction photocatalysts to improve photocatalytic performance. In this work, a novel ZIF-67/AgCl/Ag heterojunction photocatalyst was successfully synthesized by a facile chemical etching, deposition-precipitation, light-induced reduction approach. After chemical etching by a AgNO precursor, the crystal size of ZIF-67 decreased remarkably together with the replacement of Co in the framework of ZIF-67 by Ag surface ion exchange. As a result, optical and electrochemical measurements indicated that the separation efficiency of light-induced electrons and holes obviously increased due to the formation of a ZIF-67/AgCl/Ag heterojunction and the surface plasmon resonance of Ag. Meanwhile, the corresponding kinetic rate constant of ZIF-67/AgCl/Ag was estimated to be 0.1615 min, which was 17, 7.76 and 2.67 times as high as that of individual ZIF-67, AgCl and ZIF-67/AgCl, respectively. The ZIF-67/AgCl/Ag photocatalyst also exhibited good stability and reusability in the process of photodegradation. This work demonstrated a high efficiency photocatalyst for providing new sights into the preparation of a highly efficient MOF-based heterojunction photocatalyst and its potential applications in water purification.