Construction of ZnO/ZIF-9 heterojunction photocatalyst: enhanced photocatalytic performance and mechanistic insight

Abstract

Heterostructure construction in photocatalysts is an effective method to improve their catalytic activity because of the remarkable role that the heterostructure plays in charge separation. In this study, a novel photocatalyst, a ZnO/ZIF-9 heterojunction, was prepared by a facile sonocrystallization approach. The photocatalytic results showed that ZnO/ZIF-9 heterostructures with 50 wt% ZIF-9 reached the maximum degradation efficiency (around 87.7%) for TC within 1 h. The improved photocatalytic activity of the composites is primarily due to the formation of the heterojunction between ZnO and ZIF-9; therefore, the separation efficiency of electron–hole pairs can be effectively enhanced during the photocatalytic reaction. Finally, a possible mechanism to explain the improved photocatalytic performance of the photocatalytic system was proposed. More importantly, ZnO/ZIF_0.5 possesses good stability and reusability after recycling four times. This study demonstrates a promising and facile approach to construct a high efficiency heterojunction photocatalyst for the elimination of environmental pollutants.