Edge-Enriched Molybdenum Disulfide Ultrathin Nanosheets with a Widened Interlayer Spacing for Highly Efficient Gaseous Elemental Mercury Capture

Transition metal sulfides have exhibited remarkable advantages in gaseous elemental mercury (Hg0) capture under high SO2atmosphere, whereas the weak thermal stability significantly inhibits their practical application. Herein, a novel N,N-dimethylformamide (DMF) insertion strategy via crystal growth engineering was developed to successfully enhance the Hg0capture ability of MoS2at an elevated temperature for the first time. The DMF-inserted MoS2possesses an edge-enriched structure and an expanded interlayer spacing (9.8 Å) and can maintain structural stability at a temperature as high as 272 °C. The saturated Hg0adsorption capacities of the DMF-inserted MoS2were measured to be 46.91 mg·g–1at 80 °C and 27.40 mg·g–1at 160 °C under high SO2atmosphere. The inserted DMF molecules chemically bond with MoS2, which prevents possible structural collapse at a high temperature. The strong interaction of DMF with MoS2nanosheets facilitates the growth of abundant defects and edge sites and enhances the formation of Mo5+/Mo6+and S22–species, thereby improving the Hg0capture activity at a wide temperature range. Particularly, Mo atoms on the (100) plane represent the strongest active sites for Hg0oxidation and adsorption. The molecule insertion strategy developed in this work provides new insights into the engineering of advanced environmental materials.