Engineering of Defect-Rich Cu 2 WS 4 Nano-homojunctions Anchored on Covalent Organic Frameworks for Enhanced Gaseous Elemental Mercury Removal.

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 (Hg 0 ) over a wide temperature range. Herein, we constructed a defect-rich Cu 2 WS 4 nano-homojunction decorated on covalent organic frameworks (COFs) with abundant S vacancies. Highly well-dispersed and uniform Cu 2 WS 4 nanoparticles were immobilized on COFs strongly via an ion pre-anchored strategy, consequently exhibiting enhanced Hg 0 removal performance. The saturation adsorption capacity of Cu 2 WS 4 @COF composites (21.60 mg·g -1 ) was 9 times larger than that of Cu 2 WS 4 crystals, which may be ascribed to more active S sites exposed in hybrid interfaces formed in the Cu 2 WS 4 nano-homojunction and between Cu 2 WS 4 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.