Constructing Cd0.5Zn0.5S/Bi2WO6 S-scheme heterojunction for boosted photocatalytic antibiotic oxidation and Cr(VI) reduction

Abstract

The development of distinguished photocatalysts with high photo-carrier disassociation and photo-redox power for efficient elimination of pollutants in water is of great significance but still of a grand challenge. Herein, a novel Cd 0.5 Zn 0.5 S/Bi 2 WO 6 S-scheme heterojunction was built up by integrating Cd 0.5 Zn 0.5 S nanoparticles on Bi 2 WO 6 microspheres through a simple route. The S-scheme charge transfer mode substantially boosts the high-energetic electrons/holes spatial detachment and conservation on the Cd 0.5 Zn 0.5 S (reduction) and Bi 2 WO 6 (oxidation), respectively, as well as effectively suppresses the photo-corrosion of Cd 0.5 Zn 0.5 S, rendering Cd 0.5 Zn 0.5 S/Bi 2 WO 6 photocatalysts with superior redox ability. The optimal Cd 0.5 Zn 0.5 S/Bi 2 WO 6 heterojunction achieves exceptional visible-light-driven photocatalytic tetracycline (TC) degradation and Cr(VI) reduction efficiency, 3.2 (1.9)-time and 33.6 (1.6)-time stronger than that of neat Bi 2 WO 6 (Cd 0.5 Zn 0.5 S), while retaining the superior stability and reusability. Quenching test, mass spectrometry analysis, and toxicity assessment based on QSAR calculation unravel the prime active substances, intermediates, photo-degradation pathway and intermediate eco-toxicity in photocatalytic process. This research not only offers a potential photocatalyst for aquatic environment protection but also promotes the exploration of novel and powerful chalcogenides-based S-scheme photocatalysts for environment protection. A novel S-scheme heterojunction of Cd 0.5 Zn 0.5 S nanodots/Bi 2 WO 6 microspheres was designed and developed for highly efficient visible-light photocatalytic abatement of antibiotics and Cr(VI). A brand-new Cd 0.5 Zn 0.5 S/Bi 2 WO 6 S-scheme heterojunction was constructed; Cd 0.5 Zn 0.5 S/Bi 2 WO 6 demonstrates enhanced photocatalytic antibiotic degradation and Cr(VI) reduction; The degradation pathway of tetracycline was analyzed and QSAR analysis indicates that the toxicity of tetracycline was largely attenuated by Cd 0.5 Zn 0.5 S/Bi 2 WO 6 The mechanism and driving force of charge migration and separation in photoreaction were discussed; The S-scheme charge transfer mechanism ensures improved charge separation and stronger redox ability.