Edge-Enriched Molybdenum Disulfide Ultrathin Nanosheets with a Widened Interlayer Spacing for Highly Efficient Gaseous Elemental Mercury Capture
Liu Cao, Kaisong Xiang, Junyuan Li, Chaofang Li, Lele Liu, Fenghua Shen, Hui Liu
Abstract
Transition metal sulfides have exhibited remarkable advantages in gaseous elemental mercury (Hg 0 ) capture under high SO 2 atmosphere, 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 Hg 0 capture ability of MoS 2 at an elevated temperature for the first time. The DMF-inserted MoS 2 possesses 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 Hg 0 adsorption capacities of the DMF-inserted MoS 2 were measured to be 46.91 mg·g –1 at 80 °C and 27.40 mg·g –1 at 160 °C under high SO 2 atmosphere. The inserted DMF molecules chemically bond with MoS 2, which prevents possible structural collapse at a high temperature. The strong interaction of DMF with MoS 2 nanosheets facilitates the growth of abundant defects and edge sites and enhances the formation of Mo 5+ /Mo 6+ and S 2 2– species, thereby improving the Hg 0 capture activity at a wide temperature range. Particularly, Mo atoms on the (100) plane represent the strongest active sites for Hg 0 oxidation and adsorption. The molecule insertion strategy developed in this work provides new insights into the engineering of advanced environmental materials.