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

Abstract

Photocatalytic hydrogen peroxide (H₂O₂) production from water and O₂ 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 μmol 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 H₂O₂in situ. This study provides a new idea and approach for photocatalytic H₂O₂ production without using a sacrificial agent.