Direct Z-scheme WO3/covalent organic framework (COF) heterostructure for enhanced photocatalytic hydrogen peroxide production in water

Photocatalytic hydrogen peroxide (H2O2) production from water and O-2 has received considerable attention. However, most of the photocatalysts reported often require the addition of sacrificial agents to quench h(+), which greatly restricts their practical application and increases the cost. In this study, we proposed a Z-scheme heterojunction WO3/covalent organic framework (Tp-TAPB) that can accelerate the separation and charge transfer at the interface and retain the strong oxidative and reductive ability of WO3 and Tp-TAPB. The photocatalytic activity for H2O2 production of WO3/Tp-TAPB reached 1488.4 mu mol g(-1) h(-1) in a pure water system without any sacrificial agents, which is 72.3 times and 2.8 times higher than that of WO3 and Tp-TAPB, respectively. In addition, WO3/Tp-TAPB was used for photocatalytic H2O2 production in lake water and tap water, and a high photocatalytic H2O2 production rate was still maintained. The in situ photocatalytically synthesized H2O2 was used in the real coking wastewater to remove chemical oxygen demand (COD) under UV light radiation. The removal of COD was over 37% with UV/H2O2. To the best of our knowledge, there is no other study on the degradation of organic pollutants in real water by using photocatalytically synthesized H2O2 in situ. This study provides a new idea and approach for photocatalytic H2O2 production without using a sacrificial agent.