Constructed 3D hierarchical micro-flowers CoWO4@Bi2WO6 Z-scheme heterojunction catalyzer: Two-channel photocatalytic H2O2 production and antibiotics degradation

Abstract

• 3D flower-like CoWO 4 @Bi 2 WO 6 Z-scheme photocatalyst is constructed. • Multifunctional 3D CoWO 4 @Bi 2 WO 6 shows superior photocatalytic redox activity. • 3D CoWO 4 @Bi 2 WO 6 can achieve photocatalytic production of H 2 O 2 by two-channel pathway. • 3D CoWO 4 @Bi 2 WO 6 can also efficiently degrade ENR/LOM/CIP and their mix-pollutants. • Mechanism of photocatalytic H 2 O 2 production and pollutants degradation are revealed. Proper design and fabrication of multifunctional visible-light-induced photocatalysts with high catalytic efficiency is still a huge challenge for the value-added chemicals production and environmental remediation. A novel 3D flower-like hierarchical CoWO 4 @Bi 2 WO 6 Z-scheme hybrid was successfully fabricated via anchoring CoWO 4 nanoparticles on the 2D nanopetals of Bi 2 WO 6 microflower obtained by solvothermal assistant self-assembly. The multifunctional composite could markedly improve photocatalytic H 2 O 2 production via two-channel route (oxygen reduction and water oxidation reaction) without using sacrificial agent. Interestingly, 3D CoWO 4 @Bi 2 WO 6 also displayed a remarkable degradation performance on single (enrofloxacin (ENR), lomefloxacin (LOM) or ciprofloxacin hydrochloride (CIP)) and ternary mixed antibiotics (ENR + LOM + CIP) under visible light irradiation. The outstanding photocatalytic activity was primarily attributed to the 3D hierarchical CoWO 4 @Bi 2 WO 6 micro-flowers architecture for boosting visible light harvesting, matching energy band gaps, more exposed active sites, formation of Z-scheme based charge-transfer dynamics in a p-n heterostructure, as well as strong oxidation and reduction capability of photoexcited h + and e − . Therefore, it was believed that the novel multifunctional CoWO 4 @Bi 2 WO 6 photocatalyst exhibited a potential application in production of H 2 O 2 and degradation of organic contaminants, which were more significant for the following purification in industrial production and environmental governance.