Engineering of Defect-Rich Cu₂WS₄ Nano-homojunctions Anchored on Covalent Organic Frameworks for Enhanced Gaseous...

Fabricating two-dimensional transition-metal dichalcogenide (TMD)-based unique composites is an effective way to boost the overall physical and chemical properties, which will be helpful for the efficient and fast capture of elemental mercury (Hg⁰) over a wide temperature range. Herein, we constructed a defect-rich Cu₂WS₄ nano-homojunction decorated on covalent organic frameworks (COFs) with abundant S vacancies. Highly well-dispersed and uniform Cu₂WS₄ nanoparticles were immobilized on COFs strongly via an ion pre-anchored strategy, consequently exhibiting enhanced Hg⁰ removal performance. The saturation adsorption capacity of Cu₂WS₄@COF composites (21.60 mg·g^-1) was 9 times larger than that of Cu₂WS₄ crystals, which may be ascribed to more active S sites exposed in hybrid interfaces formed in the Cu₂WS₄ nano-homojunction and between Cu₂WS₄ nanoparticles and COFs. More importantly, such hybrid materials reduced adsorption deactivation at high temperatures, having a wide operating temperature range (from 40 to 200 °C) owing to the thermostability of active S species immobilized by both physical confined and chemical interactions in COFs. Accordingly, this work not only provides an effective method to construct uniform TMD-based sorbents for mercury capture but also opens a new realm of advanced COF hybrid materials with designed functionalities.