Van der Waals heterojunction engineered C3N5/laccase photo-enzyme-coupled catalyst for heterogeneous catalytic degradation of tetracycline hydrochloride

Abstract

This study introduces a novel photo-enzyme-coupled heterogeneous catalytic system, addressing limitations in traditional persulfate (PDS) photoactivation for tetracycline hydrochloride degradation. By integrating laccase with a novel carbon nitride (C₃N₅), a composite catalyst featuring a van der Waals heterojunction is formed. This heterojunction facilitates efficient charge carrier migration, with Bader charge analysis revealing a 0.2793 e transfer from laccase to C₃N₅. The resulting internal electric field and band gap structure bending enhance visible light absorption and charge carrier transfer through a type II band alignment mechanism. C₃N₅/laccase composite demonstrates improved charge carrier migration efficiency and extended photogenerated carrier lifetime. The superior charge transfer performance improves PDS adsorption and oxidative capability, significantly increasing reactive oxygen species production, particularly singlet oxygen (¹O₂) and superoxide radicals (O₂⁻·). The system achieves 86.3 % TCH degradation efficiency within 60 min. This research elucidates the mechanism of efficient PDS photoactivation via the van der Waals heterojunction and provides insights into advanced oxidation technologies for wastewater treatment. These findings contribute to the development of more efficient, environmentally friendly water treatment methodologies, advancing the field of photo-enzyme-coupled heterogeneous catalysis systems.